180 Technical Review June 2009

The Australian Wine A W R I Research Institute

Technical Review

No180 June 2009

Registered by Australia Post PP 531629/00034 Table of contents

In this issue 1 AWRI notes 5

The power of collaboration 5

Returning value to producers through providing a competitive edge 8

Technical notes 11

Grape and wine pepper aroma – analytically challenging but we sniff it out in the end 11

Practical management of hydrogen sulfide during fermentation – an updated overview according to recent studies on red wine fermentation (AWRI publication #1121) 17

Current literature 26 AWRI publications 59 AWRI extension and roadshow calendar 66 Conference calendar 67

Editor: Michael Major, Michael Major Media All enquiries: Rae Blair; email [email protected] Copyright: Reprints and quotations of articles published herein are permitted on condition that full credit is given to both The Australian Wine Research Institute Technical Review and the author/s, and that the date of publication and issue number are stated. Acknowledgment: The production and distribution of Technical Review is partially financed by The Thomas Walter Hardy Trust Fund. ISSN 0816-0805

Cnr Hartley and Paratoo Rd PO Box 197 T +61 8 8303 6600 Published by The Australian Urrbrae Glen Osmond F +61 8 8303 6601 Wine Research Institute South Australia 5064 South Australia 5064 [email protected] ABN 83 007 558 296 Australia Australia www.awri.com.au Highlights this issue

The power of collaboration...... 5

Returning value to producers through providing a competitive edge...... 8

Grape and wine pepper aroma – analytically challenging but we sniff it out in the end.... 11

Practical management of hydrogen sulfide during fermentation – an updated overview according to recent studies on red wine fermentation (AWRI publication #1121)...... 17

June 2009 Technical Review No. 180 1 Photocopy requests

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Current literature (circle the required papers) 180.01 [4.40] 180.02 [0.70] 180.03 [0.40] 180.04 [0.10] 180.05 [0.20] 180.06 [3.20] 180.07 [0.70] 180.08 [0.40] 180.09 [0.30] 180.10 [0.20] 180.11 [1.60] 180.12 [1.00] 180.13 [1.00] 180.14 [1.20] 180.15 [0.20] 180.16 [0.80] 180.17 [0.60] 180.18 [0.90] 180.19 [1.10] 180.20 [0.90] 180.21 [0.40] 180.22 [0.80] 180.23 [0.60] 180.24 [0.90] 180.25 [0.60] 180.26 [0.70] 180.27 [0.70] 180.28 [0.10] 180.29 [0.80] 180.30 [0.60] 180.31 [0.80] 180.32 [0.70] 180.33 [0.80] 180.34 [0.80] 180.35 [0.80] 180.36 [0.70] 180.37 [0.90] 180.38 [0.40] 180.39 [0.20] 180.40 [0.70] 180.41 [0.60] 180.42 [0.50] 180.43 [0.80] 180.44 [0.10] 180.45 [1.40] 180.46 [1.20] 180.47 [0.20] 180.48 [0.40] 180.49 [0.60] 180.50 [0.90] 180.51 [0.50] 180.52 [0.50] 180.53 [1.20] 180.54 [0.20] 180.55 [0.10] 180.56 [0.30] 180.57 [20.40] 180.58 [1.10] 180.59 [0.90] 180.60 [0.60] 180.61 [0.70] 180.62 [0.80] 180.63 [1.80] 180.64 [4.70] 180.65 [2.30] 180.66 [0.60] 180.67 [0.20] 180.68 [0.90] 180.69 [0.90] 180.70 [1.60] 180.71 [1.10] 180.72 [0.80] 180.73 [0.10] 180.74 [0.60] 180.75 [0.80] 180.76 [0.40] 180.77 [0.50] 180.78 [0.20] 180.79 [0.40] 180.80 [1.20] 180.81 [0.30] 180.82 [1.10] 180.83 [0.30] 180.84 [0.20] 180.85 [0.60] 180.86 [0.50]

AWRI publications (circle the required papers) 1120 [1.40] 1121 [0.80] 1122 [8.00] 1123 [1.10] 1124 [0.50] 1125 [0.60] 1126 [0.30] 1127 [0.40] 1128 [0.20] 1129 [1.10] 1130 [0.60] 1131 [0.40] 1132 [0.30] 1133 [0.80] Translation requests (circle the required papers)

A translation of any non-English articles within current literature is available upon request:

180.03 180.46 180.61 180.63 180.64 180.65 180.57 180.71 180.80 180.85

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4 Technical Review No. 180 June 2009 In this issue

AWRI notes Returning value to producers through providing a competitive edge The AWRI protects a small quantity of its website for the exclusive use of Australian grape and wine producers. This article explains what is protected and why.

The power of collaboration Between January 2007 and April 2009 the AWRI has engaged in nearly 80 collaborations with individuals and organisations from around the world. This article explains the benefits of effective collaboration and gives examples of beneficial outcomes.

Technical notes Grape and wine pepper aroma – analytically challenging but we sniff it out in the end The distinguishing pepper aroma and flavour of some Australian Shiraz wines is considered a desirable trait. The character could be thought of as quintessentially Australian and possibly part of the ‘terroir’ of a particular wine. It follows that it was important for the AWRI to identify and then attempt to understand such a powerful odorant present in grapes and wine in our own backyard.

Practical management of hydrogen sulfide during fermentation – an updated overview according to recent studies on red wine fermentation (AWRI publication #1121)

This article provides a brief overview of the many documented causes of H2S production during fermentation, their prediction and/or diagnosis, when possible, and practical control strategies.

Recent research at the AWRI suggests that residual H2S in wine depends more on the stage of fermentation when it is produced than how much is produced. Choice of yeast remains the best tool for controlling wine H2S content.

CURRENT LITERATURE Oenology

General (page 26) Catching-up trajectories in the wine sector: a comparative study of Chile, Italy and South Africa Industry supply and demand evaluation, 2009 and beyond Control of enological practices recognized internationally. A critical review AWRI: Grape berry size is not always related to quality Talent pool leads industry forward

June 2009 Technical Review No. 180 1 New tool to describe oral sensations elicited by white wine The hunt for TCA: how natural cork producers are detecting and eliminating taint from their lots

Juice and wine handling (page 29) Stuck ferments: causes and solutions Best-practice winemaking with heat-affected fruit Are wines affected by the proximity of vineyards to Eucalypt trees? Tongue-twisting Gewürtztraminer looking for its day in the sun Barbera – an ancient variety with a bright future in Australia Effect of the prefermentative addition of copigments on the polyphenolic composition of Tempranillo wines after malolactic fermentation Influence of low temperature prefermentative techniques on chromatic and phenolic characteristics of Syrah and Cabernet Sauvignon wines Whole berry destemming, sorting of red grapes

Microbiology (page 31) Co-fermentation with Pichia kluyveri increases varietal thiol concentrations in Sauvignon Blanc Ethanol stress stimulates the Ca2+-mediated calcineurin/Crz1 pathway in Saccharomyces cerevisiae

Analysis and composition (page 32) Effect of polyphenols on the perception of key aroma compounds from Sauvignon Blanc wine Sensory attribute evolution in bottled young red wines from Rioja Alavesa

Effects of elevated CO2 on grapevine (Vitis vinifera L.): volatile composition, phenolic content, and in vitro antioxidant activity of red wine Free and glycosidically bound volatiles in guava leaves (Psidium guajava L.) palmira ICA-I cultivar Factors affecting the hydroxycinnamate decarboxylase/vinylphenol reductase activity of Dekkera/ Brettanomyces: application for Dekkera/Brettanomyces control in red wine making The effect of hydroxycinnamic acids and volatile phenols in beer quality Replacement of sulfur dioxide by lysozyme and oenological tannins during fermentation: influence on volatile composition of white wines New methods to limit urea: genetically enhanced yeasts reduce probable carcinogen

Marketing and packaging (page 36) Study of suitability of 187 mL PET bottles for packaging wine in Australia Myth busting: who is the Australian cask wine consumer? Wine producers invited to share in environmental and cost benefits Life under screwcap: winemakers learn vigilance to avoid sulfide odors

Wine and health (page 37) Drinking patterns, dependency and life-time drinking history in alcohol-related liver disease Energy intake estimates of respondent-measured alcoholic beverages Impact of body weight on the relationship between alcohol intake and blood pressure Imaging of language-related brain regions in detoxified alcoholics Alcohol consumption, social support, and risk of stroke and coronary heart disease among Japanese men: The JPHC study Decrease in the prevalence of adolescent alcohol use and its possible causes in Japan: periodical nationwide cross-sectional surveys Alcohol and self-rated health in a Mediterranean country: the role of average volume, drinking pattern, and alcohol dependence Effects of beer, wine, and liquor intakes on bone mineral density in older men and women Invited commentary: Never, or hardly ever? It could make a difference

2 Technical Review No. 180 June 2009 Alcohol, wine, and vascular diseases: an abundance of paradoxes Opinions of non-pregnant New Zealand women aged 16-40 years about the safety of alcohol consumption during pregnancy Web-based screening and advice for hazardous drinkers: use of a Spanish site Low alcohol alternatives: a promising strategy for reducing alcohol related harm Functional limitations, socioeconomic status, and all-cause mortality in moderate alcohol drinkers

Environmental health (page 40) Green efforts not valued by UK wine consumers – Yalumba case study reveals Energy efficiency and sustainability Global climate change and wine production UK drinkers ‘don’t rate sustainability’ A perfect storm: how winemakers controlled wildfire smoke taint in 2008 juice, must and wine

Viticulture

General (page 42) Electrically heated cables protect vines from frost damage at early flowering Differences in the amount and structure of extractable skin and seed tannins amongst red grape varieties Understanding heatwaves in South-East Australian wine regions The mathematics of heatwaves in South-Eastern Australian winegrowing regions Use of stomatal conductance and pre-dawn water potential to classify terroir for the grape variety Kékfrankos Avoiding potential heat stress Australian Wine Environmental Stewardship demonstrates commitment to sustainability $1.8m research program sets tone for new regional node Viticulture durable en Champagne: Guide pratique 2009 Flavonol 3-O-glycosides series of Vitis vinifera cv. Petit Verdot red wine grapes Grape variety effect on proanthocyanidin composition and sensory perception of skin and seed tannin extracts from Bordeaux wine grapes (Cabernet Sauvignon and Merlot) for two consecutive vintages (2006 and 2007) Identification of anthocyanins in muscadine grapes with HPLC-ESI-MS Global viticulture: quality management systems and traceability Caring for country: post-Kyoto responses to greenhouse emissions from agriculture Actualités viticoles Le guide viti d’ACW Evolution of phenolic composition of Sagrantino grapes during maturation Ethylene and other stimuli affect expression of the UDP glucose-flavonoid 3-0-glucosyltransferase in a non-climacteric fruit Berry abscission is related to berry growth in Vitis labruscana ‘Concord’ and Vitis vinifera ‘Riesling’

Vine propagation and improvement (page 50) Comparison of enzymes involved in sugar metabolism from Shang-24 (Vinifera quinguangularis) and Cabernet Sauvignon (Vinifera vinifera) at veraison Anthocyanin fingerprint of clones of Tempranillo grapes and wines made with them Clonal diversity of Zinfandel Search for Primitivo (V. vinifera L.) variability in Apulia Molecular identification and genetic relationships of Algerian grapevine cultivars maintained at the germplasm collection of Skikda (Algeria)

June 2009 Technical Review No. 180 3 Pests and diseases (page 53) Infection of grapevines with Pseudomonas syringae in a frost-prone region Stem application of metalaxyl for the protection of Vitis vinifera L. (‘Riesling’) leaves and grapes against downy mildew (Plasmopara viticola)

Nutrition, soil and water (page 54) Response of potted grapevines to increasing soil copper concentration Irrigation management options during veraison Problem weeds in Australian vineyards Impact of low irrigation goes on trial Correlations among ground penetrating radar, electromagnetic induction and vine trunk circumference data: towards quantifying terroir in New Zealand Pinot Noir vineyards Evaluation of the vine growth status by the ‘shoot tip method’ Impact of the vine water status on the berry and seed phenolic composition of ‘Merlot’ (Vitis vinifera L.) cultivated in a warm climate: consequence for the style of wine

Vineyard canopy management (page 56) Site, vine state and responsiveness to the application of growth regulator fruitsetting agents Shoot-positioning made easy The impacts of root-pruning on early and late bunch stem necrosis Effect of cluster thinning at fruit set and veraison, over productive, vegetative and enological parameters in (Vitis vinifera L.) cv. Tannat Effects of the whole vine versus single shoot-crop level on fruit growth in Vitis labruscana ‘Concord’

AWRI publications (page 59) Isolation of sulfite reductase variants of a commercial wine yeast with significantly reduced hydrogen sulfide production Effect of nitrogen supplementation and Saccharomyces species on hydrogen sulfide and other volatile sulfur compounds in Shiraz fermentation and wine Yeast and wine flavour Discovering a chemical basis for differentiating wines made by fermentation with ‘wild’ indigenous and inoculated yeasts: role of yeast volatile compounds Quantification of several 4-alkyl substitutedγ -lactones in Australian wines Brines, paints, oils and the occasional mobile phone – common vintage contaminants Unleashing the secrets of organic wine grown in Australia using infrared light Riesling acetal is a precursor to 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) in wine Managing fruitset in vineyards Mouthfeel of white wines made with and without pomace contact and added anthocyanins Managing oxygen ingress at bottling What the Chinese want To your health Identification of yeast population dynamics of spontaneous fermentation in Beijing wine region, China

4 Technical Review No. 180 June 2009 AWRI notes The power of collaboration

Collaboration is an essential part of the research community and forms part of everything we do at the AWRI. Effective collaboration is entered into freely, by parties with mutual intent, high trust and with complementary skills and knowledge.

To achieve the goals of the AWRI’s Business Plan and Research, Development and Extension Plan, the AWRI has engaged in hundreds of active partnerships with companies, institutions and government bodies both locally and internationally. The AWRI has a long history of successfully managing cooperative partnerships for the mutual benefit of the AWRI, its partners and the Australian wine sector. These partnerships generate beneficial knowledge greater than the sum of the individuals working alone.

The AWRI’s recent move into the Wine Innovation Cluster’s WIC Central Building is one example of a major initiative aimed at building the frameworks that foster effective collaboration. The WIC Central Building accommodates the AWRI with the grape and wine scientists of The University of Adelaide and the South Australian Research and Development Institute (SARDI). Our clustering with these organisations and with our other WIC members, CSIRO Plant Industry and Provisor, provides strength in diversity and alignment with similarity of spirit. The WIC partners have complementary assets and talents and the AWRI will continue to foster linkages with them and other national and international collaborators to the benefit of partners, stakeholders and the whole Australian wine sector. This cooperation enables us separately and together to bag a greater number of goals for Brand Australia.

Some examples of effective collaboration • The key peppery aroma compound in Shiraz grapes and wine (and other important spices) was identified as rotundone. This was achieved through a collaboration between the AWRI and a German flavour company. Now that the compound has been identified, research is underway to give Australian producers the tools to manage rotundone levels in their grapes and wine. • Through the collaborative efforts of the AWRI, the University of Adelaide and Curtin University, the aroma-less (non-volatile) precursors to the key marker compound of smoke taint, guaiacol, were detected in smoke-affected grapes. This knowledge gives growers and winemakers the capability to predict which grapes will produce wines with undesirable ‘smoke taint’.

June 2009 Technical Review No. 180 5 • By working together, the AWRI, the Australian Genome Research Facility and a US biotechnology company were the first to complete the genome sequence of wine yeast and conduct a comparative study of several yeast genomes. With the ingredients of this recipe now available, researchers can attempt to pinpoint which parts of the wine yeast are responsible for key components in wine. • Through productive research contracts with AB Mauri, Lallemand and Anchor Yeast, the AWRI was able to develop and facilitate access by Australian producers to: novel Saccharomyces

bayanus yeasts; hybrid yeasts; H2S-minus yeasts; and yeast blends. This gives winemakers greater control over creating wines that their customers want to drink. • A project completed by the AWRI and Chemical Engineering at the University of Adelaide about a year ago highlighted opportunities to reduce white wine losses in bentonite lees. One of these opportunities included tank or in-line dosing of bentonite, followed by centrifugation for separation of bentonite lees and clarification of the wine. Centrifugation reduced the volume of bentonite lees nearly five-fold, recovering substantial quantities of occluded wine which otherwise would have been lost or downgraded during recovery. This project was considered by the Council of Rural Research and Development Corporation Chairs (CRRDCC) in its broader evaluation of the impact of research and development funded by Research and Development Corporations in Australia. This evaluation involved an economic analysis of the cost and benefits that R&D conducted in this project would achieve. The analysis concluded that the project would ‘generate significant net benefits to the Australian community’ with an estimated net present value of $98 m over 30 years. • Non-destructive analysis of bottled wine components and classifying unknown bottles of wine is now possible through a commercial collaboration involving the AWRI, a software company and an engineering company. The technology and the equipment will soon be available to wine producers. • Together with Universities in Victoria, Western Australia and Queensland, the AWRI is developing a strategic capability in microbial metabolomics. The study of an organism’s metabolites, metabolomics, is expected to become as important as genomics and proteomics in securing fundamental scientific understanding and delivering relevant outcomes of benefit to producers. • By being part of the consortium that approached the Australian Government for funding for research into Pinot Noir and Sparkling wine production, the AWRI was able to establish a ‘node’ and research program in Tasmania. This enables an enhanced effort into understanding the process and problems of cool climate wine production in Australia. Consortium partners were the AWRI, Wine Industry Tasmania, TIAR, Tamar Ridge Estate, Flextank, and Croplands.

6 Technical Review No. 180 June 2009 • The AWRI engaged key grape and wine research providers in South Australia and, together, were able to realise the vision of an integrated cluster to enhance effective grape and wine research outcomes. The Wine Innovation Cluster commenced physical operation in October 2008, and involves the AWRI, The University of Adelaide, SARDI, CSIRO Plant Industry and Provisor.

Our current collaborators Apart from the many informal collaborations amongst scientists at the AWRI and other individuals and organisations, the map below illustrates the number of contractual collaborations that the AWRI entered into between January 2007 and April 2009.

12 7

1 54

We welcome approaches from organisations who can bring complementary knowledge and skills to a partnership with the AWRI. Further information about our activities are available from our website: www.awri.com.au.

Dr Dan Johnson, General Manager – Business Development, [email protected]

June 2009 Technical Review No. 180 7 Returning value to producers through providing a competitive edge

The AWRI protects a small quantity of its website for the exclusive use of Australian grape and wine producers. So why is this? Why isn’t all of the website content available to any visitor to the site?

The management of the AWRI website is funded by an annual grant from the Grape and Wine Research and Development Corporation (GWRDC). TheGWRDC invests the funding it receives from the levies paid by Australian grapegrowers and winemakers, and the matching funding contributed by the Australian government. So, the website’s existence and ongoing maintenance and development is funded by Australian winemakers, grapegrowers and taxpayers. Access to the website is offered at no additional cost to approved users.

The AWRI’s aim for its website is to provide a powerful source of knowledge and tools that help to keep Australian grape and wine producers informed, innovative, competitive and sustainable. The website is a culmination of information that has developed (and continues to develop) from over 54 years of the AWRI’s interaction with Australian producers.

Of the >12,000 pages of information on the website, more than 80% is available to any visitor to the site. We continue to invest in developing the website on an on-going basis, with the aim of continuously improving the tools and information available for the betterment of the Australian grape and wine sector.

So, what areas of the website are only available to Australian producers and why? The AWRI has developed some tools, funded by the GWRDC, which are available on the AWRI website that provide value to Australian producers. Some examples of what sections of the website that Australian producers alone can access is below:

• Self-diagnosis for wine hazes and deposits • Wine production calculators • AWRI staff presentations as webcasts • Abstracts and, where available, full text articles for grape and wine technical literature • The full text of the AWRI’s bimonthly publication,Technical Review • Practical sensory evaluation in the winery • AWRI Agrochemical Online Search Facility

8 Technical Review No. 180 June 2009 The development of the above content was made possible through GWRDC funding and it was decided to reserve access to this information for the exclusive benefit of Australian winemakers and grapegrowers. However, any other stakeholders within the Australian grape and wine sector can contact the AWRI Library (email: [email protected]) with requests for specific information.

The development of the extensive database of grape and wine technical literature – providing abstracts and where available, full text of articles, was made available through individual copyright agreements with publishers from around the world on the basis it be available only to Australian grape and wine producers. So, by law, access must be controlled.

It is important to note that the AWRI staff presentations as webcasts have also been made available to Australia’s future grape and wine workforce through access granted to Universities and their students.

What are some examples of information freely available on the website? As some 80% of the website is available to any visitor, only some examples of the more popular sections of the site are provided below:

• Agrochemical information, Spray Diary and maximum residue limits (MRL) database • Grape and Wine Web search portal allows keyword searching across 25 wine and grape sector websites • Permitted additives and processing aids database • Wine and environment database • Wine and health section • How to establish a winery laboratory • Ordering copies of AWRI Staff publications • AWRI Online Image Collection • AWRI Annual Reports

How do Australian producers obtain a password? Australian winemakers and grapegrowers are encouraged to set up an account by visiting the website and by following the prompts online at http://www.awri.com.au/users/. Queries can be directed to the AWRI Library via email: [email protected]

What’s in store for the website in the future? The AWRI website has been identified as a key resource for the rapid adoption of cutting-edge research and practical tools for the Australian wine sector. We are constantly aiming to add new

June 2009 Technical Review No. 180 9 and exciting content, and invest in new information dissemination technologies to the benefit of all stakeholders in the sector.

We welcome any feedback to assist us to ensure the AWRI website meets the needs of Australian grape and wine producers.

Con Simos, Group Manager, Industry Development and Support Rae Blair, Communication Manager, [email protected] Sean Boden, Systems Librarian

10 Technical Review No. 180 June 2009 Technical notes Grape and wine pepper aroma – analytically challenging but we sniff it out in the end

Introduction The importance of aroma compounds to wine quality and style is of undoubted significance. Aroma compounds in wine arise from a variety of sources, such as from the grape berry either in free or bound form, from fermentation of juices and musts to produce wine or from oak contact and ageing. There is a vast number of chemical entities that produce the various aromas, from simple fermentation esters to amino acid- or peptide-bound thiols and glycosidically-bound terpenes, to name just a few. Not only this, there is large variation in the aroma detection thresholds of grape and wine components, making some classes more potent than others, and also enormous differences in the amounts of various compounds present in grapes or wine.

All this leads to a very challenging task for the analysis of aroma compounds and precursors in grapes and wine. It can be likened to trying to find a needle in a haystack. This oversimplifies the situation though, as it assumes there is knowledge about what the needle looks like. To highlight the analogy of looking for that needle without knowing how it looks, the topical discovery of a potent peppery compound in Australian Shiraz wines will be discussed, along with data obtained for this compound from various studies at the AWRI.

Waiter, I’d like some pepper in my Shiraz! The distinguishing pepper aroma and flavour of some Australian Shiraz wines is considered a desirable trait. One only needs to look at tasting notes on the internet or read the labels of Australian Shiraz wine bottles to realise this is true. The pepper character could be thought of as quintessentially Australian and possibly even part of the ‘terroir’ of a particular wine. It follows that it was important for the AWRI to identify and then attempt to understand such a powerful odorant present in grapes and wine in our own backyard.

Several years ago the story began with sensory and analytical studies, where a peppery character was identified in Australian Shiraz grapes from different regions and vintages (AWRI publication #990). Initially, despite the appreciable work performed during this time, only a marker compound α-ylangene could be identified in grapes. This marker compound was associated with grape pepper intensity as rated by a sensory panel. Interestingly, this marker was not peppery itself, and was not detected in any wines analysed that were described as peppery. At the time it was stated in AWRI publication #990:

June 2009 Technical Review No. 180 11 “It is possible that α-ylangene is not directly related to the still unknown ‘spicy’/‘pepper’ flavor compound(s) in Shiraz grapes but rather reflects other factors that could be responsible for the development of the ‘spicy’/‘pepper’ character in grapes such as cool climate, grape variety, cultivar or possibly clone, grapegrowing location or region, or other factors.”

Sniffing out the pepper compound Being the tenacious types that scientists generally are, the matter was not put to rest with this development, as the actual pepper compound was yet to be identified. So back to the instruments we trudged for another couple of years of work. The next phase involved a technique known as gas chromatography-mass spectrometry-olfactometry (GC-MS-O). This is a technical way of saying compounds in grape and wine samples were separated on an instrument and sniffed. GC-MS-O is one of the rare techniques where a human organ, the nose, is used as a detection device which is often more sensitive than the electronic detector in use (the MS part). This was definitely the case with the elusive pepper compound.

For the sake of brevity, years of hard work have been condensed into several sentences. A combination of skill, determination and ingenuity enabled enough material to be isolated for GC- MS-O analysis. With analysts displaying great patience and allowing the instrument to run longer than would normally be done for such detective work, a distinct pepper aroma was detected in one discrete zone from grape extracts (AWRI publication #1060). Additional work on peppercorns enabled enough compound to be isolated, with identical characteristics to the compound in grape extracts, for a mass spectrum or ‘chemical fingerprint’ to be determined. This would not have been the end of the story had we not sought advice from flavour experts at Symrise, who had this ‘chemical fingerprint’ in their database. It turned out that the potent pepper aroma was due to a compound called rotundone, which we also found to be highly abundant in peppercorns. Synthesis of this compound and a deuterated analogue (required to accurately quantify rotundone in samples) followed, as did development of an analytical method applicable to grapes and wine (AWRI publication #1061).

As is often the case in scientific discoveries, luck plays a part and although unknown at the time, luck was on our side. A peculiar aspect of aroma compounds is that not everyone is able to detect their odour, even at concentrations well above their sensory threshold [rotundone thresholds were determined to be 8 ng/L in water and 16 ng/L in red wine (AWRI publication #1060)]. This was certainly evident for rotundone, where around 20% of sensory panellists could not detect this compound even at 500 times the threshold in water (AWRI publication #1060). Fortunately, some of our scientists working on this project were very sensitive to rotundone aroma, or this compound would still be awaiting discovery.

12 Technical Review No. 180 June 2009 From grapes to wine – where to now for rotundone? With the identification and analytical method hurdles overcome, we have started testing some of the theories first raised in the original paper for drivers of pepperiness, such as grape variety, cultivar, clone type and region. For instance, it is known that rotundone levels vary between vineyards and between vintages within the same vineyard (AWRI publication #990; AWRI publication #1060), but the reasons for this are undetermined. Further studies could be performed on grapes or wine coming from relevant vineyard or vintage trials. Additional avenues to explore are the stability of rotundone in wine-like solutions and the effect of scalping by closures.

A useful starting point when a new compound is identified is to survey a selection of wines, to assess the distribution and to help guide further studies. We undertook rotundone analyses of a large range of commercially available Australian wines (137 predominantly red wines obtained from local retailers) of different varieties and vintages from various regions. The majority were bottled either under screwcap or natural cork and included Shiraz, Merlot, Durif, Pinot Noir, Cabernet Sauvignon and several other interesting wines from popular winegrowing regions from the early 1990s until 2006. The vast majority (81%) of the wines had no detectable rotundone (of the wines that contained rotundone, 62% were Shiraz); Figure 1 shows the amounts of rotundone encountered and wine variety/region in samples where the compound was present. From Figure 1 it is apparent that above-threshold levels of rotundone (>16 ng/L) are often encountered in wines originating from cool climate regions, which is in agreement with previous observations (Iland and Gago 1995; AWRI publication #1060). This survey helped to narrow our focus for the grape studies, as we aimed to further our knowledge of viticultural drivers of pepper character.

Rotundone Levels in Commercial Australian Wines 180 161 152 160

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R o 60 37 39 38 32 33 35 40 28 25 16 16 7 11 11 10 10 11 9 20 3 3 4 2 3 0 n s n y y y n o n n e d a e a a n g n e r a r l t t e e e i o s a l r a l l l o n d d a r n y y a c l l l u u n r i g i s i d e a s s a r e e d s e l l e e s o l r i a a a r g l e b n w n p l l l l l g Y a l l t l i e i i l l n k b v V a V a V a e / a i s e L i n e

e c m u r o i m n r e s n H H h n V a r n n c l s a e R a o t l V a V a a a D i o l o a r a r a R r a r a r a B a u G M A d A d G M C P e o T F H C a a a G R M C Y Y Y

z r f ra i ri i o u o N n g Sh t D a in o ci sl n ra ie Region/Variety Pi G R Figure 1. Results for commercial Australian wines where rotundone was present

June 2009 Technical Review No. 180 13 While we cannot provide a great deal of insight into the viticultural drivers for pepper character at present, mainly due to the inconsistencies from vintage to vintage even within known ‘peppery vineyards’, we have concentrated on the prevalence and persistence of this character in wine. An ongoing study is looking at the effects of several closures on rotundone levels in bottled wine, to determine whether the compound is ‘scalped’ by the closure, as is the case with other aroma compounds (AWRI publication #744).

A finished but unwooded experimental Shiraz wine was spiked with rotundone and bottled under three different closures. The same wine was analysed immediately after preparation to determine the time zero value, and was also sealed in ampoules which served as controls for a number of time points. Figure 2 shows the results of the time points analysed to date (all analyses were conducted in triplicate), with the results expressed as the percentage of the original amount that remained in the wine. Over this relatively short time period there was no dramatic change in rotundone levels, and the three closures performed very similarly. The results for the closures are only slightly lower than the six-month control sample (glass ampoule) where no scalping can take place.

In addition to the scalping experiments we wanted to assess the stability of rotundone during storage. Studies into the stability of rotundone under wine-like and accelerated ageing conditions showed no striking effects on rotundone concentration. The major compound formed under accelerated ageing conditions was determined to be the hydrated form (essentially the chemical addition of water) of rotundone, but the position of hydration was not ascertained. The stability of rotundone under wine-like conditions and the relative lack of scalping of the compound indicate that the pepper characteristics of a particular wine at bottling are unlikely to change drastically

Scalping of Rotundone by Closures t n

u 100% o m

g 80% A n i

n 60% i a a n i g m 40% i r e R

O 20% f o

0% l l e E E c c l a a % i i k k r r T T t t s u r r k k u u s e e o r r t t o o O O a h h l p o o a a R R t t C C C C n n G N N m y y a S S

3 Months 6 Months Closure/Time Point Figure 2. Extent of scalping by various closures relative to initial amount spike into wine. Error bars represent %RSD for triplicate analyses, which was <10% in all cases

14 Technical Review No. 180 June 2009 over time with proper storage conditions. Indeed, a Shiraz wine from the Grampians region with the highest level of rotundone (161 ng/L) appearing in Figure 1 was from the 2002 vintage, while another Grampians region Shiraz from 1999 still had 152 ng/L present some 10 years after bottling. Although we could not have analysed these wines when they were released so no direct comparison can be made, and a number of factors can influence rotundone concentration, these examples tend to indicate the relative stability of the compound over many years.

Work in progress – back to the grapes We wanted to assess the impact of region and climate, and even differences in clonal aspects on the presence of rotundone in grapes. Considering the compound is typically found in Shiraz grapes this is where we have focussed our attention in the first instance. We have initiated vintage studies with grapegrowers and winemakers from a number of interesting cool climate regions that have been identified as having high pepper potential. We have collected samples at different grape maturation stages and will also obtain wine made from those particular vineyard patches. Included in these samples are a number of different Shiraz clones sourced from the different regions and also viticultural trials designed to assess the impact of vine vigour on grape rotundone content.

Summary The identification of the pepper compound called rotundone in grapes and wine was the culmination of many years of research. A combination of staff dedication, advanced instrumental techniques, serendipity, synthetic capability and collaboration all helped to shine light on the elusive pepper compound. A method was developed for the analysis of rotundone in grapes and wine and we are now starting to see the fruits of that labour.

A great majority of wines analysed in a large survey of commercial Australian wines had no rotundone present, yet varieties other than Shiraz have been shown for the first time to contain rotundone. Experiments conducted to assess scalping by closures and stability of rotundone in wine-like systems have shown this to be a persistent compound relatively unaffected by closure type or ageing.

The studies performed so far have allowed us to identify predominantly cool climate regions as the best areas to assess the impact of viticulture on wine rotundone levels, and this will be the focus of our current and future work. With the knowledge available to date, the single biggest factor affecting rotundone levels is related to seasonal variation between vintages, so finding reliably peppery vineyards to study has been a major challenge.

June 2009 Technical Review No. 180 15 References AWRI publication #744. Capone, D., Sefton, M., Pretorius, I., Høj, P. (2003) Flavour ‘scalping’ by wine bottle closures – the ‘winemaking’ continues post vineyard and winery. Aust. N.Z. Wine Ind. J. 18: 16, 18–20. AWRI publication #990. Parker, M., Pollnitz, A.P., Cozzolino, D., Francis, I.L., Herderich, M.J. (2007) Identification and quantification of a marker compound for ‘pepper’ aroma and flavor in shiraz grape berries by combination of chemometrics and gas chromatography-mass spectrometry. J. Agric. Food Chem. 55: 5948–5955. AWRI publication #1060. Wood, C., Siebert, T.E., Parker, M., Capone, D.L., Elsey, G.M., Pollnitz, A.P., Eggers, M., Meier, M., Vossing, T., Widder, S., Krammer, G., Sefton, M.A., Herderich, M.J. (2008) From wine to pepper: rotundone, an obscure sesquiterpene, is a potent spicy aroma compound. J. Agric. Food Chem. 56: 3738–3744. AWRI publication #1061. Siebert, T.E., Wood, C., Elsey, G.M., Pollnitz, A.P. (2008) Determination of rotundone, the pepper aroma impact compound, in grapes and wine. J. Agric. Food Chem. 56: 3745–3748. Iland, P., Gago, P. (1995) Discovering Australian Wine – A Taster’s Guide. Patrick Iland Wine Promotions, Adelaide, Australia.

David Jeffery, Senior Research Scientist,[email protected] u Tracey Siebert, Senior Scientist Dimitra Capone, Senior Scientist Kevin Pardon, Technical Officer Katryna van Leeuwen, Technical Officer Mark Solomon, Technical Officer

16 Technical Review No. 180 June 2009 Practical management of hydrogen sulfide during fermentation – an updated overview according to recent studies on red wine fermentation (AWRI publication #1121)

The sporadic occurrence of H2S during fermentation continues to be an annual winemaking problem, due to the association of this compound with ‘reductive’ off-flavours that are strongly detrimental to wine quality (Mestres et al. 2000). Just as is the case for stuck fermentations, laboratory studies have likewise identified many sources of H2S and other volatile sulfur compounds (VSC) in fermentation (AWRI publications #401, 973, 1122, Monk 1986, Rauhut 1993, 2009).

It is largely for this reason that H2S is usually detected in at least several fermentations in any given winery every vintage. All must types, whether red, white, rosé, sparkling or botrytis-affected, are susceptible to H2S development. Winemakers have reported associations between H2S production and certain vineyards and also most yeast strains. However, despite considerable laboratory-based research carried out world-wide, we have only few tools for predicting which ferments will produce

H2S and associated ‘reductive’ flavours.

H2S can occur at any stage during fermentation but is most commonly observed during the early stages, less often during the late stages and sometimes throughout fermentation (Figure

1). However, in practice, the causes of H2S evolution are rarely determined, since predicting or diagnosing H2S production is particularly difficult in complex matrices like grape juice and wine.

Consequently, wines that have been exposed to H2S during fermentation are typically treated with copper sulfate to remove detectable residual sulfidic or ‘reductive’ odour. While copper sulfate is effective against 2H S and thiols (mercaptans, e.g. methane and ethane thiols) it does not remove disulfides (Zoecklein et al. 1995). Disulfides represent a latent form of sulfides in wine, which under certain conditions, such as highly reductive storage or packaging, can (unexpectedly) reappear (Limmer 2005). Furthermore, free copper cations can react with other chemical constituents of wine or mediate oxidation reactions that can lead to a decrease in the intensity of wine aroma and sometimes loss of varietal characters. For example, copper cations react with the fruity, long-chain, polyfunctional thiols in Sauvignon Blanc and related varieties (Darriet et al. 2001, Ellett et al.

2008), which causes difficulties when trying to selectively remove2 H S.

The implications of H2S occurrence during fermentation are still not well understood. H2S that forms early in fermentation is simply considered by many winemakers to be a nuisance and not as important as H2S that is formed during the late stages of fermentation. This scenario can be explained by the fact that during the yeast growth phase the associated high fermentation vigour leads to a rapid loss of the highly volatile H2S by entrainment with CO2. On the contrary, when fermentation vigour is low, any H2S which forms is less efficiently removed from the wine, and

June 2009 Technical Review No. 180 17 less so in large fermentors. Whether or not H2S reacts with other compounds in the wine to produce mercaptans, mercaptan esters and more complex volatile sulfur compounds (disulfides, thiazoles, etc.) is not well understood (Rauhut 2009, AWRI publication #1122). Yeasts are known to synthesise mercaptans and related VSC but the factors that affect this in the winemaking environment are not yet well described (Rauhut 2009, AWRI publication #1122). The implications of retained H2S and VSC in finished wines are obvious with respect to packaging decisions (AWRI publication #863). This topic is the subject of current research at the AWRI in collaboration with international groups and progress will be reported in the near future.

This short overview will highlight the more important causes and prevention strategies for controlling H2S production during white and red table wine fermentation.

Table 1 summarises the known sources of H2S which accumulates during fermentation; the likely mechanisms involved in its production; and potential strategies for ameliorating or limiting the problem. Suggested methods for prediction and diagnosis of H2S production are also included in the table.

Early-mid e a s t

Y phase or

growth Yeast-must

associated interaction

Late phase

H2S associated

or non-growth

H S 2 associated

H S 2

YAN S 2 H

Fermentation duration

Figure 1. Diagrammatic representation of H2S production by yeast during fermentation in a low nutrient juice or must. Early-mid phase or growth associated H2S (solid dark gray line) generally commences as yeast assimilable nitrogen (YAN; solid dark gray block) becomes undetectable and peaks as yeast growth enters stationary phase (dashed grey line). The rate of decline in H2S production (solid and dotted dark grey lines) is associated with yeast strain and undefined must factors. Prolonged H2S production (dotted dark grey line) can lead to residual H2S in the finished wine and is generally associated with low fermentation vigour. Certain yeast strains in combination with certain juices/musts can produce H2S for an extended period and throughout fermentation (solid light grey line). Late phase or non-growth associated H2S production (solid black line) typically commences when residual sugar is <50–100 g/L and can continue until the end of fermentation or shortly after. Late production of H2S is most associated with significant residual H2S in wine (AWRI publication #1121).

18 Technical Review No. 180 June 2009 Agrochemicals and metals Several agrochemicals contain elemental or organic S, which can potentially lead to VSC formation (Table 1). Elemental S is probably the major risk but when used in accordance with manufacturers’ recommendations the risk is minimised (Monk 1986, Thomas et al. 1993). Highest risk is associated with hot and dry weather that can dramatically bring forward the harvest date, thereby leading to higher levels of residual S in the must. Options to limit wine H2S content including washing fruit, if possible, minimising juice solids associated with S-residues and early racking to limit chemical reduction to H2S in yeast lees. Sparging wine with inert gas always remains an option, although this runs the risk of also sweeping away desirable volatile wine components.

Metal cations might also play a role in the introduction of H2S to wines, if late season additions of agrochemicals containing manganese or zinc are made to grapes (Zoecklein et al. 1995) (Table 1). Manganese and zinc can react with tartaric and malic acids to produce ‘nascent’ hydrogen which reduces SO2 to H2S (Rankine 1989). Copper sulfate is often added after fermentation as a fining agent to wines with relative success and thus should not cause any additional problems if fining trials are conducted, as recommended, such as by Iland et al. (2004). However, only the highest quality copper salts should be used, as the AWRI has detected the presence of metal impurities in one brand of copper sulfate available on the market. Copper fining is recommended immediately post-fermentation since copper addition during active fermentation can stimulate H2S production, as also occurs with many other metal cations (Zn2+, Cr3+, Fe2+, Mn2+) (Monk 1986).

It is possible that elemental metals might also play a role in H2S formation or loss if non- stainless steel constructed equipment is used during harvest, transport, must/juice processing and fermentation (Table 1). H2S can be produced from stainless-steel tanks that have not been ‘passified’ after production. Manganese sulfide can form on the surface of the stainless-steel and liberate H2S when wine contacts it. This can be avoided by rinsing the tank with citric or tartaric acid to remove the sulfide layer (Rankine 1989).

Must, nutrient and yeast factors

It is generally agreed that nutrient deprivation during fermentation is a common cause of H2S production, especially in wine regions in which the content of nutrients in musts and juices is consistently low (AWRI publication #875). The depletion of YAN is a common cause, especially the H2S that results from the early stages of fermentation when yeast growth is active (Figure 1; early-mid phase or growth associated H2S). Growth-associated H2S production results from grape must that does not contain sufficient organic sulfur (cysteine and methionine). Therefore the yeast must synthesise these amino acids by first reducing inorganic sulfur (sulfate and SO2 when added) to H2S and then combining the sulfide with metabolically derived C-N precursor compounds. The demand for N is high during yeast growth, which in low YAN musts leads to a deficit of C-N

June 2009 Technical Review No. 180 19 Table 1. Origin of H2S during fermentation and management strategies Source Mechanism Prevention Prediction/Diagnosis Agrochemicals e.g. elemental S chemical reduction i) limit S use i) risk if elemental S used ii) observe agrochemical ii) risk if with-holding period with-holding period not observed iii) lower suspended solids iii) risk with certain fungicides iv) early racking-off lees iv) delayed racking after fermentation/’dirty’ lees

Metal cations yeast metabolism, i) avoid late applications of i) risk with fungicides that e.g. zinc, copper chemical reduction agrochemicals containing contain certain cations manganese and zinc ii) avoid Cu++ fining during ii) high Cu++ fermentation

Metals chemical reduction acid rinse new stainless risk if must exposed to e.g. steel tanks steel tanks non-‘passified’ metals

Inorganic sulfur e.g. sulfate, bioreduction – sulfate i) choice of yeast strain i) known H2S producer yeast sulfite reduction pathway ii) adequate nutrients ii) low YAN/Diagnosis: DAP

induced by nutrient suppresses H2S depletion stress iii) low vitamins/Diagnosis: vitamins or inactivated yeast

supplements suppress H2S iv) limit excessive sulfite iv) increased potential for

addition some yeast to produce H2S

Organic sulfur e.g. cysteine, i) degradation of i) early racking-off lees i) delayed racking after methionine protein fermentation

ii) S-amino acid ii) choice of yeast strain ii) known H2S producer yeast degradation – iii) adequate nutrients iii) low YAN or vitamins/ induced by nutrient Diagnosis: DAP, vitamins or depletion stress inactivated yeast supplements

suppress H2S iv) less reductive ferment iv) highly reductive conditions conditions, e.g. aeration

Wild yeast bioreduction-induced i) suppress with chemical i) high wild yeast population

by nutrient depletion (e.g. SO2) or physical stress methods ii) use selected yeast strain ii) failure of inoculated yeast iii) low YAN or vitamins/ Diagnosis: DAP, vitamins or inactivated yeast supplements

suppress H2S iv) less reductive ferment iv) highly reductive conditions conditions, e.g. aeration

YAN, yeast assimilable nitrogen; DAP, diammonium phosphate. Adapted from Monk (1986) and Henschke (unpublished)

20 Technical Review No. 180 June 2009 precursor compounds, thereby leading to H2S release from the cell. In many cases this cause can be ameliorated by the addition of DAP or proprietary fermentation nutrient preparations that contain inorganic or organic N (Table 1). It should be noted that some commercial inactivated yeast preparations do not contain sufficient N to be effective in this role. When DAP or other

N supplements fail to suppress H2S production this usually signals that nitrogen deficiency is not the cause, or that supplementation was inadequate in relation to the N requirements of the yeast. A deficiency of one or more vitamins has also been associated with 2H S production (AWRI publications #401, 498, Fugelsang and Edwards 2007). Pantothenic acid and pyridoxine have been implicated. The availability of these vitamins in Australian musts is unknown. Addition of yeast vitamin preparations or inactivated yeast preparations (used in accordance with wine production regulations) in this situation can control H2S production, confirming such a deficiency (Table 1).

Sulfite can be a preferred source of H2S in some fermentation yeast (Hallinan et al. 1999), however, careful consideration should be given to lowering SO2 addition at harvest, transport and must preparation when the strong antimicrobial and antioxidant actions of SO2 are needed.

Work in progress at the AWRI suggests that some yeast strains produce H2S at low to moderate levels in the early stages of fermentation, which sometimes continues throughout fermentation. These strains also appear to be largely unresponsive to the addition of N and vitamins or inactivated yeast-containing nutrients (Figure 1; yeast-must interaction associated H2S). The cause of this H2S production is unknown and seems to be the result of interactions by particular combinations of yeast strain and juice/must (AWRI publication #498). Further research is being conducted to gain a better understanding of this occurrence.

Late phase H2S production occurs after yeast growth has finished and typically late in fermentation when <50–100 g/L of sugar remains (Figure 1; late phase or non-growth phase associated H2S) (AWRI publication #514). Some varieties, such as Shiraz seem to be more susceptible than other varieties, such as Cabernet Sauvignon. Some yeast strains also appear to be more susceptible than others. Although YAN is generally undetectable in the later stage of fermentation, H2S production at this stage is typically unresponsive to DAP addition. Some ferments respond to aeration (pump-over, rack and return) or vitamin supplements, though H2S production might simply be lowered and not eliminated. It is believed that yeast are mobilising reserves of organic S compounds (methionine, cysteine, glutathione) as sources of N for cell maintenance activities.

Recovery of N from these compounds leads to the release of H2S (Hallinan et al. 1999, AWRI publication #1122). It is important to note that using aeration to lower H2S concentration can lead to the formation of disulfides, if mercaptans are also present. Therefore, while this treatment might appear to have removed H2S, disulfides might in fact be produced, with the potential to produce ‘reductive’ flavours when conditions permit.

June 2009 Technical Review No. 180 21 Timing of H2S production

Our recent research is strongly implicating the timing of H2S production during fermentation to be a highly important factor in determining the occurrence of residual H2S in finished wine (AWRI publication #1121). This work, which was undertaken with a low YAN Shiraz must, showed that if H2S production ceased before approximately the mid-point of fermentation then no H2S could be detected in the (cold-settled) wines after fermentation. However, if the yeast continued to produce H2S beyond the mid-point of fermentation then significant H2S could be found in the wines. This work therefore suggests that H2S produced after the vigorous stage of fermentation may be considerably more important for wine residual H2S than that which forms early in fermentation. However, as with all laboratory-based investigations, this finding needs to be verified under winery conditions. Work in progress will establish the role played by mercaptans that are concomitantly produced with H2S by many strains of yeast (Rauhut 2009, AWRI publication #1121), and consequently the tools available for effectively controlling the formation of ‘reductive’ flavour compounds.

Predicting H2S production

Predicting whether a juice or must will produce H2S during fermentation is not yet possible, largely because multiple factors are involved, which can occur singularly or in combinations. However, some rapid methods are available to measure H2S, which can be used to screen the ability of different juices and juice/yeast combinations to produce 2H S, as well as for the monitoring of

H2S formation during winery fermentations. These include selective H2S detector tubes and the

Nitrogenius® kit. The AWRI is currently working to optimise a rapid procedure to monitor 2H S formation in laboratory and winery fermentations. Juice/must analysis is, however, a useful tool. Analysis of grape juice samples world-wide suggests strongly that all juices have extremely low concentrations of assimilable forms of organic S-compounds: principally cysteine and methionine, but adequate concentrations of inorganic sulfur, such as sulfate and SO2 (AWRI publication #401). Consequently, yeast require C-N precursor compounds, which they must derive from sugar and other amino acids to produce S-amino acids. Therefore, measuring YAN is a useful indicator of the potential for H2S production; several studies suggest that >250 mg/L YAN in must suppresses

H2S produced by most wine yeast strains (AWRI publication #875). Determining S-amino acids and inorganic S in juice/must samples seems to have limited predictive power but more research is needed. Measurement of key vitamins has not been tested, since under normal winemaking practice these are probably not deficient. However, certain practices can lead to key vitamin deficiency, such as poor hygienic conditions from vineyard to the fermentation tank. If this occurrence is suspected, then addition of a vitamin or inactivated yeast preparation is likely to be useful.

The choice of yeast strain remains as one of the most important factors in limitingH 2S production during fermentation. Since the early days of research at the AWRI on H2S, Dr Bryce Rankine

22 Technical Review No. 180 June 2009 identified high variability amongst yeast with respect to 2H S production (AWRI publication #23), which has been repeatedly verified by others (AWRI publication #486, Spiropoulis et al. 2000). Various attempts have been made to breed yeast strains with commercially unimportant levels of H2S production by selection and gene technologies. Recently, Dr Toni Cordente and colleagues from the AWRI have produced non-genetically modified (non-GM) industrially useful strains (AWRI publication #1120), which are now available from Mauri Yeast Australia (AWRI publication #1018). Yeast strains, such as these, will become a tool of choice when limitation of

H2S production is necessary.

Wild yeasts

The role of indigenous or wild yeasts as a source of H2S when juices/musts have been inoculated with a selected yeast is unclear. According to the ‘old’ wine literature wild yeasts were a major source of H2S during fermentation but the growing interest in wines made by fermentation with

‘wild’ yeasts suggests that H2S production is not a major issue. Recent research at the AWRI in collaboration with two Australian wine companies suggests that residual H2S in wines made with indigenous yeasts, when compared with selected strains, is only marginally higher (AWRI publication #1123). Managing H2S production in wild yeast fermentations is similar to that of inoculated ferments.

Managing varietal character

Managing H2S in Sauvignon Blanc, Merlot and other varieties, in which thiols are important to varietal character, appears to present a special winemaking problem. Very recent research has shown that one of the putative precursors for the two key Sauvignon Blanc aroma compounds 3-mercaptohexanol and 3-mercaptohexyl acetate (often referred to as 3MH and 3MHA) is taken-up by yeast from grape juice by the N-scavenging permease known as General Amino Acid permease (GAP1p) (Subileau et al. 2008, Thibon et al. 2008). This permease is only active when ammonium ions have been depleted from the juice and hence the cysteinylated precursor for 3MH is not taken up and converted to 3MH during the first days of fermentation. Addition of DAP, depending on the amount used, to increase the YAN content of low N juices and/or to limit H2S production, can consequently delay or even prevent uptake of this precursor and consequent release of the fruity thiol aroma compounds. On the other hand, supplementing fermentations with commercial inactivated yeast preparations, which contain low levels of inorganic N, does not compromise the production of fruity thiols but can even enhance their production (AWRI publication #1021). Furthermore, as already mentioned, fining H2S with copper salts is limited by the fact that 3MH and other related desirable thiols can concomitantly be removed (Ellett et al. 2008), which might be more important in wines with low concentrations of varietal thiols.

June 2009 Technical Review No. 180 23 Any queries regarding the treatment of ‘reductive’ characters during winemaking should be directed to the AWRI’s Winemaking and Extension Services team on tel: (08) 8303 6600 or email: [email protected].

References and further reading AWRI publication #23. Rankine, B.C. (1963) Nature, origin and prevention of hydrogen sulphide aroma in wines. J. Sci. Food Agric. 14: 79–91. AWRI publication #401. Henschke, P.A., Jiranek, V. (1991) Hydrogen sulfide formation during fermentation: effect of nitrogen composition in model grape must. Proceedings of the International Symposium on Nitrogen in Grapes and Wine, Seattle, USA. American Society for Enology and Viticulture: Davis, CA, pp. 172–184. AWRI publication #486. Jiranek, V., Langridge, P., Henschke, P.A. (1995) Validation of bismuth-containing indicator media

for predicting H2S producing potential of Saccharomyces cerevisiae wine yeasts under enological conditions. Am. J. Enol. Vitic. 46: 269–273. AWRI publication #498. Henschke, P.A., de Kluis, F.M. (1995) Origin and control of hydrogen sulfide produced by yeast during fermentation. Proceedings of the XXI World Congress of grapes and wines, Punte del Este, Uruguay. Office International de la Vigne et du Vin: Paris, France, pp. 165–178. AWRI publication #514. Henschke, P.A. (1996) Hydrogen sulfide production by yeast during fermentation. Proceedings Eleventh international oenological symposium, Sopron, Hungary International Association for Winery Technology and Management: Breisach, Germany, pp. 83–102. AWRI publication #863. Godden, P., Lattey, K., Francis, L., Gishen, M., Cowey, G., Holdstock, M., Robinson, E., Waters, E., Skouroumounis, G., Sefton, M., Capone, D., Kwiatkowski, M., Field, J., Coulter, A., D’Costa, N., Bramley, B. (2005) Towards offering wine to the consumer in optimal condition – the wine, the closures and other packaging variables. Aust. N.Z. Wine Ind. J. 20(4): 20–30. AWRI publication #875. Bell, S.-J., Henschke, P.A. (2005) Implications of nitrogen nutrition for grapes, fermentation and wine. Aust. J. Grape Wine Res. 11: 242–295. AWRI publication #973. Swiegers, J.H., Pretorius, I.S. (2007) Modulation of volatile sulfur compounds by wine yeast. App. Microbiol. Biotechnol. 74: 954–960. AWRI publication #1018. Cordente, T., Heinrich, A., Swiegers, H. (2007) A new revolution in wine: yeast strains that produce no detectable hydrogen sulphide. Aust. N.Z. Grapegrower Winemaker 526: 110–114. AWRI publication #1021. Swiegers, H., Ugliano, M., van der Westhuizen, T., Bowyer, P. (2008) Impact of yeast rehydration on the aroma of Sauvignon Blanc wine. Aust. N.Z. Grapegrower Winemaker (528): 68–71. AWRI publication #1120. Cordente, A.G., Heinrich, A., Pretorius, I.S., Swiegers, J.H. (2009) Isolation of sulfite reductase variants of a commercial wine yeast with significantly reduced hydrogen sulfide production. FEMS Yeast Res. DOI:10.1111/j.1567-1364.2009.00489.x AWRI publication #1121. Ugliano, M., Fedrizzi, B., Siebert, T., Travis, B., Magno, F., Versini, G., Henschke, P.A. (2009) Effect of nitrogen supplementation and Saccharomyces species on hydrogen sulfide and other volatile sulfur compounds in Shiraz fermentation and wine. J. Agric. Food Chem. DOI:10.1021/jf8037693. AWRI publication #1122. Ugliano, M., Henschke, P.A. (2009) Yeast and wine flavour.Moreno-Arribas, V., Polo, M.C. (Eds.). In Wine Chemistry and Biochemistry. New York: Springer, Chapter 8D, pp. 313–392. AWRI publication #1123. Varela, C., Siebert, T., Cozzolino, D., Rose, L., McLean, H., Henschke, P.A. (2009) Discovering a chemical basis for differentiating wines made by fermentation with ‘wild’ indigenous and inoculated yeasts: role of yeast volatile compounds. Aust. J. Grape Wine Res. DOI: 10.1111/j.1755-0238.2009.00054.x. Darriet, P., Bouchilloux, P., Poupot, C., Bugaret, Y., Clerjeau, M., Sauris, P., Medina, B., Dubourdieu, D. (2001) Effects of copper fungicide spraying on volatile thiols of the varietal aroma of Sauvignon Blanc, Cabernet Sauvignon and Merlot wines. Vitis 40: 93–99. Ellett, N., Butler, P., Kilmartin, P.A., Nicolau, L. (2008) The effect of copper sulfate fining on varietal thiols and reductive compounds in Sauvignon Blanc wines. Blair, R.J.; Williams, P.J.; Pretorius, I.S. (eds.). Proceedings of the thirteenth Australian wine industry technical conference, 29 July–2 August 2007, Adelaide, SA: Australian Wine Industry Technical Conference Inc., Adelaide, SA., 397–398.

24 Technical Review No. 180 June 2009 Fugelsang, K.C., Edwards, C.E. (2007) Wine microbiology. Practical applications and procedures. Second edition. NY: Springer, pp. 128–129.

Hallinan, P., Saul, D.J., Jiranek, V. (1999) Differential utilisation of sulfur compounds for 2H S liberation by nitrogen-starved wine yeasts. Aust. J. Grape Wine Res. 5: 82−90. Iland, P., Bruer, N., Ewart, A., Markides, A., Sitters, J. (2004) Monitoring the winemaking process from grapes to wine: techniques and concepts. Patrick Iland Wine Promotions Pty Ltd, Campbelltown, SA, pp. 78–79. Limmer, A. (2005) Suggestions for dealing with post-bottling sulfides. Aust. N.Z. Grapegrower Winemaker (503): 67, 69–74, 76. Mestres, M., Busto, O., Guasch, J. (2000) Analysis of organic sulfur compounds in wine aroma. J. Chromatogr., A 881: 569–581. Monk, P.R. (1986) Formation, utilisation and excretion of hydrogen sulphide by wine yeast. Aust. N.Z. Wine Ind. J. 1: 10–16. Rankine, B.C. (1989) Making good wine—a manual of winemaking practice for Australia and New Zealand. Melbourne: Sun Books.: 280. Rauhut, D. (1993) Yeasts – production of sulfur compounds. In: Wine Microbiology and Biotechnology. Fleet, G.H. (ed.). Chur, Switzerland: Harwood Academic Publishers. Chapter 6, pp. 183–224. Rauhut, D. (2009) Usage and formation of sulphur compounds. König, H., Unden, G., Frölich, J. (eds.). In: Biology of Microorganisms on Grapes, in Must and in Wine. Heidelberg, Germany: Springer: Chapter 10, pp. 181–207. Spiropoulos, A., Tanaka, J., Flerianos, I., Bisson, L.F. (2000) Characterization of hydrogen sulfide formation in commercial and natural wine isolates of Saccharomyces. Am. J. Enol. Vitic. 51: 233–248. Subileau, M., Schneider, R., Salmon, J.-M., Degryse, E. (2008) Nitrogen catabolite repression modulates the production of aromatic thiols characteristic of Sauvignon Blanc at the level of precursor transport. FEMS Yeast Res., 8: 771–780. Thibon, C., Marullo, P., Claisse, O., Cullin, C., Dubourdieu, D., Tominaga, T. (2008) Nitrogen catabolic repression controls the release of volatile thiols by Saccharomyces cerevisiae during wine fermentation. FEMS Yeast Res. 8: 1076–1086. Thomas, C.S., Boulton, R.B., Silacci, M.W., Gubler, W.D. (1993) The effect of elemental sulfur, yeast strain, and fermentation medium on hydrogen sulfide production during fermentation. Am. J. Enol. Vitic. 44: 211–216. Zoecklein, B.W., Fugelsang, K.C., Gump, B.H., Nury, F.S. (1995) Wine analysis and production. New York: Chapman and Hall, pp. 168–177.

Maurizio Ugliano, Research Scientist, [email protected] Gal Winter, PhD student Adrian Coulter, Senior Oenologist Paul Henschke, Principal Research Scientist

June 2009 Technical Review No. 180 25 Current literature

Copies of all articles listed in this section are available for private study

on request from the AWRI. Please use the request form provided in the centre pages of this issue. Currently a service charge of A$7.00 per request is applicable, plus a supply charge of 10¢ per page, plus postage will apply (inclusive of GST).

In compliance with copyright legislation, abstracts are reproduced here exactly as originally printed.

Oenology General

180.01 Cusmano, L., Morrison, A., Rabellotti, R. Catching-up trajectories in the wine sector: a comparative study of Chile, Italy and South Africa. AAWE Working Paper 34, 1–44; 2009.

Abstract not available for reproduction

180.02 Stanford, L. Industry supply and demand evaluation, 2009 and beyond. Aust. Vitic. 13(1), 12–18; 2009.

Australian Wine and Brandy Corporation information and analysis manager, Lawrie Stanford, told attendees at the 2008 Australian Wine Outlook Conference that factors such as water availability and an unfavourable exchange rate are among several issues affecting the assessment of supply and demand for the Australian wine sector.

26 Technical Review No. 180 June 2009 180.03 Curvelo-Garcia, A.S. Control of enological practices recognized internationally. A critical review. Ciência Téc. Vitiv. 23(2), 119–122; 2009.

[Portuguese] Description of an enological practice will be including the objective, the application area and their limits and, if applicable, the additives and technological auxiliaries concerned. The International Code of Enological Practices and the Enological Codex of OIV respect these criteria. So, considering the applications limits of these enological practices, it is indispensable the availability of methodologies to control the proper application of these practices. But in the Code of Enological Practices of OIV, there is a great need of these control methodologies, concluding for the necessity of distinguishing the information prescriptions on the use of the enological practices (like integrating a ‘Code of Good Practices’) of the compulsory prescriptions (necessary to the food security guard of the products and the loyalty of the competitiveness).

© Reprinted with permission from Curvelo-Garcia, A.S. Control of enological practices recognized internationally. A critical review. Ciência Téc. Vitiv. 23(2), 119–122; 2009. Copyright 2009 Estação Vitivinícola Nacional.

A translation of the above article is available at a charge of $5 per page.

180.04 Cummins, E. AWRI: Grape berry size is not always related to quality. GrapeGrowers Vignerons March, p23; 2009.

A study of the effect of different pruning methods on grapes, quality and other characters of wine has found that wines made from smaller berries produced from machine pruned vines record a lower quality score. The other methods of cane or spur pruning produced higher quality scores consistently during the three vintages of the study, while the nature of the vintages had a greater effect on quality than the method of pruning. These findings resulted from a study of vines in a single vineyard in South Australia’s Clare Valley, owned by Constellation Wines Australia, which wanted to determine how pruning could affect the quality, sensory characters including aroma - and mouth-feel of its wines.

180.05 De Cicco, R. Talent pool leads industry forward. GrapeGrowers Vignerons February, 4–5; 2009.

This article profiles a diverse mix of participants who will feature in this year’s national wine industry leadership and development program, ‘Future Leaders – Succession for the Australian Wine Sector’.

June 2009 Technical Review No. 180 27 L 180.06 Pickering, G.J. New tool to describe oral sensations elicited by white wine. Pract. Winery Vineyard Jan/Feb, 74–105; 2009.

Through extensive sensory panel work involving 136 wines and 21 sessions, a lexicon, set of definitions, evalulation protocol, and reference standards have been developed to describe and measure the oral sensations elicited by white wine, including table, sparkling, dessert, dealcoholized, and fortified styles.

© Reprinted with permission from Pickering, G.J. New tool to describe oral sensations elicited by white wine. Pract. Winery Vineyard Jan/Feb, 74–105; 2009. Copyright 2009 Practical Winery and Vineyard Incorporated.

180.07 Goode, J. The hunt for TCA: how natural cork producers are detecting and eliminating taint from their lots. Wines Vines January, 56–62; 2009.

Quality control measures are being used to prevent contaminated cork from being turned into closures that then leave the factory. Some cork manufacturers are using extractive or washing methods to destroy TCA, the most dramatic example being that used by Oeneo’s DIAM closures. One metric indicates average cork taint by bale has decreased from 4 ppt in 2001 to less than 1 ppt in 2008. Full article available online at http://winesandvines.com/template.cfm?section=features&content=61247&ftitl e=The%20Hunt%20for%20TCA.

© Reprinted with permission from Goode, J. The hunt for TCA: how natural cork producers are detecting and eleminating taint from their lots. Wines Vines January, 56–62; 2009. Copyright 2009 The Hiaring Company.

28 Technical Review No. 180 June 2009 Juice and wine handling

180.08 Bowyer, P.K., van der Westhuizen, T., Grbin, P.R., Rusted, S., Schiller, N. Stuck ferments: causes and solutions. Aust. N.Z. Grapegrower Winemaker 542, 58–61; 2009.

Yeast nutrition, or lack thereof, is identified as a major contributor to stuck fermentation problems. This article presents steps that can minimise risk and maximise wine quality.

© Reproduced with permission from Bowyer, P.K., van der Westhuizen, T., Grbin, P.R., Rusted, S., Schiller, N. Stuck ferments: causes and solutions. Aust. N.Z. Grapegrower Winemaker 542, 58–61; 2009. Copyright 2009 Winetitles Pty Ltd.

180.09 Howard, C. Best-practice winemaking with heat-affected fruit. Aust. N.Z. Grapegrower Winemaker 541, 38–40; 2009.

There are several points in the winemaking process where winemakers have some choices as to which practices they could adopt to deal with the challenges of hot seasonal conditions. This article discusses timing of harvest; grape receival, crushing and pressing; white juice fining and fermentation.

180.10 Lindh, K. Are wines affected by the proximity of vineyards to Eucalypt trees? Aust. N.Z. Grapegrower Winemaker 541, 56–57; 2009.

A US study has shown that the presence of 1,8-cineole (eucalyptol) plays an important role in the occurrence of ‘eucalyptus’ character in wine. The AWRI conducted experiments in 2007 to further investigate this question. Preliminary studies show that eucalyptol was only found in significant quantities in red wine.

180.11 Jones, L (ed.). Tongue-twisting Gewürtztraminer looking for its day in the sun. Aust. N.Z. Wine Ind. J. 24(1), 63–78; 2009.

Gewürztraminer is difficult to grow and perhaps even more difficult to pronounce but that hasn’t stopped pioneering producer of the variety, David Ritchie of Delattite Winery in Central Victoria, from believing it will one day gain acclaim among a developing niche market. In this varietal report, top Gewürztraminer C

June 2009 Technical Review No. 180 29 L producers share their ideas about what makes a quality grape and a top drop and how to entice wine drinkers to give Gewürztraminer a go. The report also includes a tasting of 18 Gewürztraminers from Australia and New Zealand.

180.12 Hook, D. Barbera – an ancient variety with a bright future in Australia. Aust. Vitic. 13(1), 74–83; 2009.

The area of Barbera under vine in Australia is declining but demand is forecast to increase, primarily for use as a secondary blending variety. This varietal report shares the experiences of some of Australia’s leading Barbera growers.

180.13 Álvarez, I., Aleixandre, J.L., García, M.J., Lizama, V., Aleixandre-Tudó, J.L. Effect of the prefermentative addition of copigments on the polyphenolic composition of Tempranillo wines after malolactic fermentation. Eur. Food Res. Technol. 228(4), 501–510; 2009.

Abstract available online from http://www.springerlink.com/content/1438-2377

180.14 Gil-Muñoz, R., Moreno-Pérez, A., Vila-López, R., Fernández-Fernández, J.I., Martínez- Cutillas, A., Gómez-Plaza, E. Influence of low temperature prefermentative techniques on chromatic and phenolic characteristics of Syrah and Cabernet Sauvignon wines. Eur. Food Res. Technol. 228(5), 777–788; 2009.

Abstract available online from http://www.springerlink.com/content/1438-2377

180.15 Whole berry destemming, sorting of red grapes. Pract. Winery Vineyard Jan/Feb, 27–28; 2009.

This article provides details of a grape destemming and sorting system that handles a typical daily volume of 40 to 60 tonnes.

30 Technical Review No. 180 June 2009 Microbiology

180.16 Anfang, N., Brajkovich, M., Goddard, M.R. Co-fermentation with Pichia kluyveri increases varietal thiol concentrations in Sauvignon Blanc. Aust. J. Grape Wine Res. 15(1), 1–8; 2009.

Background and Aims: Volatile varietal thiols are one class of yeast metabolite that add aroma/flavour to Sauvignon Blanc, particularly to the Marlborough style from New Zealand. While various strains of Saccharomyces cerevisiae are known to liberate such thiols, there are no data examining whether non-Saccharomyces species effect concentrations of these thiols in wine. Methods and Results: We screened a variety of New Zealand wine yeast isolates and found some that were able to liberate either 3-mercaptohexan-1-ol (3MH) or 3-mercaptohexyl acetate (3MHA). We show that co-fermentation with specific commercial strains and an isolate of Pichia kluyveri from New Zealand, at a 1:9 starting ratio, significantly enhances the 3MHA concentrations in Sauvignon Blanc compared with single species ferments. Conclusions: Co-fermentation with this isolate of P. kluyveri may provide a means to elevate 3MHA concentrations in Sauvignon Blanc; the mechanism behind this increase is unknown. Significance of the Study: Techniques that allow the predictable manipulation of varietal thiols potentially provide tools for winemakers to alter wine style without the use of genetically modified organisms.

© Reprinted with permission from Anfang, N., Brajkovich, M., Goddard, M.R. Co-fermentation with Pichia kluyveri increases varietal thiol concentrations in Sauvignon Blanc. Aust. J. Grape Wine Res. 15(1), 1–8; 2009. Copyright 2009 Australian Society of Viticulture and Oenology.

180.17 Araki, Y., Wu, H., Kitagaki, H., Akao, T., Takagi, H., Shimoi, H. Ethanol stress stimulates the Ca2+-mediated calcineurin/Crz1 pathway in Saccharomyces cerevisiae. J. Biosci. Bioeng. 107(1), 1–6; 2009.

Environmental stimuli elicit a stress response, which helps to maintain cell survival. In budding yeast Saccharomyces cerevisiae, environmental cues can activate calcineurin, a highly conserved Ca2+- and calmodulin-dependent protein phosphatase. Calcineurin dephosphorylates the transcription factor Crz1, leading to accumulation of Crz1 in the nuclei and expression of stress responsive genes under the control of a calcineurin-dependent response element (CDRE). Ethanol is the final product of sugar fermentation by yeast, and thus a frequently encountered yeast stressor. However, adaptation of yeast to ethanol stress is poorly understood. In this study, we show that ethanol stimulates calcineurin-dependent nuclear localization of Crz1 and CDRE-dependent gene expression. Moreover, cells in which CRZ1 is deleted exhibit defective adaptation to ethanol stress, while a multicopy plasmid of CRZ1 confers an increased level of adaptive stress tolerance to ethanol. Taken together, the results indicate that ethanol activates the calcineurin/Crz1 pathway and that CRZ1 is crucial for cell survival under ethanol-induced stress.

© Reprinted with permission from Araki, Y., Wu, H., Kitagaki, H., Akao, T., Takagi, H., Shimoi, H. Ethanol stress stimulates the Ca2+-mediated calcineurin/Crz1 pathway in Saccharomyces cerevisiae. J. Biosci. Bioeng. 107(1), 1–6; 2009. Copyright 2009 The Society for Bioscience and Bioengineering. C

June 2009 Technical Review No. 180 31 L Analysis and composition

180.18 Lund, C.M., Nicolau, L., Gardner, R.C., Kilmartin, P.A. Effect of polyphenols on the perception of key aroma compounds from Sauvignon Blanc wine. Aust. J. Grape Wine Res. 15(1), 18–26; 2009.

Background and Aims: Sensory wine research has mainly focused on the role of volatile compounds and their contribution to the aroma profile. Wines also contain polyphenolic compounds, which are not volatile. This research begins to investigate the interactions of volatile and non-volatile wine compounds and the consequential effects on sensory perception of aroma.Methods and Results: Tra ine d panellists of this study measured the perception of four aroma compounds (isobutyl methoxypyrazine, 3-mercaptohexanol, 3-mercaptohexanol acetate and ethyl decanoate) in wine. Panellists assessed the four compounds in combinations with three polyphenols (catechin, caffeic acid and quercetin) commonly found in white wine. The perception of isobutyl methoxypyrazine, 3-mercaptohexanol and ethyl decanoate was largely suppressed by the added polyphenols, while the perception of 3-mercaptohexanol was accentuated with the addition of caffeic acid. Of the three polyphenols, only catechin had a slight effect of accentuating the mercaptohexanol acetate perception. Conclusions: Results showed each polyphenol had a unique effect when blended with a specific aroma compound, either suppressing, accentuating or showing little effect on the perception of the aroma compounds. Significance of the Study: Understanding these interactions can assist winemakers in managing polyphenol levels to optimize selected volatile compounds to achieve desirable aroma profiles.

© Reprinted with permission from Lund, C.M., Nicolau, L., Gardner, R.C., Kilmartin, P.A. Effect of polyphenols on the perception of key aroma compounds from Sauvignon Blanc wine. Aust. J. Grape Wine Res. 15(1), 18–26; 2009. Copyright 2009 Australian Society of Viticulture and Oenology.

180.19 Etaio, I., Elortondo, F.J.P., Albisu, M., Gaston, E., Schlich, P. Sensory attribute evolution in bottled young red wines from Rioja Alavesa. Eur. Food Res. Technol. 228(5), 695–705; 2009.

Abstract available online from http://www.springerlink.com/content/1438-2377

180.20 Goncalves, B., Falco, V., Moutinho-Pereira, J., Bacelar, E., Peixoto, F., Correia, C. Effects of elevated CO2 on grapevine (Vitis vinifera L.): volatile composition, phenolic content, and in vitro antioxidant activity of red wine. J. Agric. Food Chem. 57(1), 265–273; 2009.

The impact of elevated carbon dioxide concentration ([CO2]) on the quality of berries, must, and red wine (with special reference to volatile composition, phenolic content, and antioxidant activity) made from Touriga Franca, a native grape variety of Vitis vinifera L. for Port and Douro wine manufacturing

32 Technical Review No. 180 June 2009 grown in the Demarcated Region of Douro, was investigated during 2005 and 2006. Grapevines were grown either in open-top chambers (OTC) with ambient (365 ± 10 ppm) or elevated (500 ± 16 ppm)

[CO2] or in an outside plot. In general, the increase of [CO2] did not affect berry characteristics, especially the total anthocyan and tannin concentrations. However, the total anthocyan and polyphenol concentrations of the red wine were inhibited under elevated [CO2]. The antioxidant capacity of the wines was determined by DPPH, ABTS, and TBARS assays and, despite the low concentrations of phenolics, the elevated [CO2] did not significantly change the total antioxidant capacity of the red wines. Thirty-five volatile compounds belonging to seven chemical groups were identified: C6 alcohols, higher alcohols, esters, terpenols, carbonyl compounds, acids, volatile phenols, and C13 norisoprenoids. Generally, the same volatile compounds were present in all of the wines, but the relative levels varied among the treatments. The effect of elevated [CO2] was significant because it was detected as an increase in ethyl 2-methylbutyrate, isoamyl acetate, ethyl hexanoate, ethyl octanoate, butyric acid, and isovaleric acid concentrations and a decrease in ethyl acetate concentration when compared to wines produced in ambient [CO2] in 2005. In elevated [CO2], wines from 2006 had lower methionol, 1-octanol, and

4-ethylguaiacol and higher ethyl lactate and linalool concentrations. The increase in [CO2] did not significantly affect C6 alcohols, citronellol, carbonyl compounds, and β-damascenone concentrations.

This study showed that the predicted rise in [CO2] did not produce negative effects on the quality of grapes and red wine. Although some of the compounds were slightly affected, the red wine quality remained almost unaffected.

Effects of elevated CO2 on grapevine (Vitis vinifera L.): volatile composition, phenolic content, and in vitro antioxidant activity of red wine. J. Agric. Food Chem. 57(1), 265–273; 2009. Copyright 2009 American Chemical Society.

180.21 García, M., Quijano, C.E. Free and glycosidically bound volatiles in guava leaves (Psidium guajava L.) palmira ICA-I cultivar. J. Essent. Oil Res. 21(Mar/Apr), 131–134; 2009.

Free and glycosidically bound volatiles obtained from the guava leaves (Psidium guajava L.) by liquid- liquid extraction and by chromatography, followed by enzymatic hydrolysis with non-selective pectinase respectively, were analyzed by capillary GC and GC/MS analyses. A total of 39 free volatiles were detected (total amount of 1328 µg/ kg), with the major components being a-copaene, β-caryophyllene, and cadina-1,4-diene. Among the 47 detected glycosidically bound compounds (total amount of 7050 µg/kg), hexanol, benzyl alcohol, and (E)-3-hexenoic acid were found to be the major constituents. In aroma evaluation, the free volatile fraction showed a guava leaf-like aroma whereas the bound fraction was odorless. However, the characteristic herbaceous-green-fatty aroma was noted in the bound fraction after enzymatic hydrolysis. Upon the combination of the free and hydrolyzed bound fractions, a strongly fresh, guava leaf-like aroma was perceived.

© Reprinted with permission from Garcia, M., Quijano, C.E. Free and glycosidically bound volatiles in guava leaves (Psidium guajava L.) palmira ICA-I cultivar. J. Essent. Oil Res. 21(Mar/Apr), 131–134; 2009. Copyright 2009 . C

June 2009 Technical Review No. 180 33 L 180.22 Benito, S., Palomero, F., Morata, A., Calderón, F., Suárez-Lepe, J.A. Factors affecting the hydroxycinnamate decarboxylase/vinylphenol reductase activity of Dekkera/Brettanomyces: application for Dekkera/Brettanomyces control in red wine making. J. Food Sci. 74(1), 15–22; 2009.

The growth ofDekkera /Brettanomyces yeasts during the ageing of red wines—which can seriously reduce the quality of the final product—is difficult to control. The present study examines the hydroxycinnamate decarboxylase/vinylphenol reductase activity of different strains of Dekkera bruxellensis and Dekkera anomala under a range of growth-limiting conditions with the aim of finding solutions to this problem. The yeasts were cultured in in-house growth media containing different quantities of growth inhibitors such as ethanol, SO2, ascorbic acid, benzoic acid and nicostatin, different sugar contents, and at different pHs and temperatures. The reduction of p-coumaric acid and the formation of 4-ethylphenol were periodically monitored by HPLC-PDA. The results of this study allow the optimization of differential media for detecting/culturing these yeasts, and suggest possible ways of controlling these organisms in wineries.

© Reprinted with permission from Benito, S., Palomero, F., Morata, A., Calderón, F., Suárez-Lepe, J.A. Factors affecting the hydroxycinnamate decarboxylase/vinylphenol reductase activity ofDekkera /Brettanomyces: application for Dekkera/Brettanomyces control in red wine making. J. Food Sci. 74(1), 15–22; 2009. Copyright 2009 Institute of Food Technologists.

180.23 Iyuke, S.E., Madigoe, M., Maponya, R. The effect of hydroxycinnamic acids and volatile phenols in beer quality. J. Inst. Brew. 114(4), 300–305; 2008.

Abstract available online at http://www.scientificsocieties.org/jib/abstracts/2008/G-2009-0105-549. htm

34 Technical Review No. 180 June 2009 180.24 Sonni, F., Bastante, M.J.C., Chinnici, F., Natali, N., Riponi, C. Replacement of sulfur dioxide by lysozyme and oenological tannins during fermentation: influence on volatile composition of white wines. J. Sci. Food Agric. 89(4), 688–696; 2009.

Background: In recent years the use of sulfur dioxide, a commonly used additive in winemaking, has been questioned because of its toxic effects on human health. Studies have been conducted to find alternatives that can effectively substitute for this additive in all its various technological functions. In previous work, lysozyme and oenological tannins were found as possible substitutes in controlling bacterial undesirable fermentations and phenolic oxidation. However, data on the volatile composition of wines obtained by that protocol are lacking. In this work, the effects on volatile composition of white wines by the substitution of SO2 during fermentation with lysozyme and tannin were studied. At the same time, the technological performance of two strains of yeast that produce low amounts of SO2 were evaluated. Results: The results showed that both SO2 and lysozyme prevented the development of undesirable bacterial fermentations. The study of volatile compounds shows differences in the alcohol, acid and ester contents among the final products: wines fermented with strain 1042 and lysozyme had higher total alcohol concentration, while the addition of SO2 promoted higher production of 3-methyl- 1-butanol, 3-methylthio-1-propanol, phenylethyl alcohol and 4-hydroxy-benzenethanol. Esters, as a total, were influenced by the different strain and tannins addition, while amounts of medium-chain fatty acid ethyl esters and their corresponding fatty acids were found in higher amounts in wines coming from fermentations with lysozyme. The sensory analysis revealed a preference for wines to which lysozyme and tannins had been added. Conclusion: The data suggest that the addition of lysozyme and oenological tannins during alcoholic fermentation could represent a promising alternative to the use of SO2 and for the production of wines with reduced content of SO2. The composition of the volatiles in the final wines was affected by the different vinification protocols (mainly with regards to alcohols and ethyl esters).

© Reprinted with permission from Sonni, F., Bastante, M.J.C., Chinnici, F., Natali, N., Riponi, C. Replacement of sulfur dioxide by lysozyme and oenological tannins during fermentation: influence on volatile composition of white wines. J. Sci. Food Agric. 89(4), 688–696; 2009. Copyright 2009 Society of Chemical Industry.

June 2009 Technical Review No. 180 35 L 180.25 Patterson, T. New methods to limit urea: genetically enhanced yeasts reduce probable carcinogen. Wines Vines February, 52–57; 2009.

European food safety bodies seem to be moving toward mandatory standards for urea and ethyl carbamate (EC) in wine, thus potentially affecting the North American wine export market. Information about vineyard and cellar methods for limiting the production of urea and EC has been available for a decade. A new development comes in the form of genetically enhanced yeast strains that produce lower levels of urea at the end of fermentation.

Marketing and packaging

180.26 Matthews, I., Vale, C. Study of suitability of 187 mL PET bottles for packaging wine in Australia. Aust. N.Z. Wine Ind. J. 24(1), 31–37; 2009.

Polyethylene cerephthalate (PET) is a type of plastic that can be made into various shaped containers by the process of blow moulding. PET has been found to be particularly suitable in the beverage industry but has not been widely used in the packaging of wine principally because PET is semipermeable to oxygen. Recently, it has been possible to incorporate an oxygen scavenger in PET during manufacture. The oxygen scavenger is depleted by its contact with oxygen which imposes a shelf life on the container. The suitability of PET as a container for wine was studied in this report. A 187 mL claret bottle was chosen for the study because a commercial supply was available and Portavin Melbourne (PVM) was able to handle 187 mL glass bottles. This report is in abridged form with the full version available at www.portavin.com.au

© Reprinted with permission from Matthews, I., Vale, C. Study of suitability of 187 mL PET bottles for packaging wine in Australia. Aust. N.Z. Wine Ind. J. 24(1), 31–37; 2009. Copyright 2009 Winetitles Pty Ltd.

180.27 Mueller, S., Umberger, W. Myth busting: who is the Australian cask wine consumer? Aust. N.Z. Wine Ind. J. 24(1), 52–58; 2009.

In this first of a two-part article, the authors go myth busting about the identity of the Australian cask wine consumer.

36 Technical Review No. 180 June 2009 180.28 Wine producers invited to share in environmental and cost benefits. Food 23 February, 1–1; 2009.

Full article available online at http://www.foodmag.com.au/Article/Wine-producers-invited-to-share- in-environmental-and-cost-benefits/438306.aspx.

180.29 Patterson, T. Life under screwcap: winemakers learn vigilance to avoid sulfide odors. Wines Vines January, 48–55; 2009.

Screwcaps promised to make worrying about closures a thing of the past, but the reality has been a little more complicated. Because screwcaps make for a more anaerobic environment than other closures, reductive potential in wine can be brought to the fore, resulting in sulfide off-odors. The key to preventing such issues, veteran screwcappers say, is eternal vigilance during the entire winemaking cycle, dealing with problems when they are detected and before bottling.

Wine and health

180.30 Hatton, J., Burton, A., Nash, H., Munn, E., Burgoyne, L., Sheron, N. Drinking patterns, dependency and life-time drinking history in alcohol-related liver disease. Addiction 104(4), 587–592; 2009.

Abstract available online at http://www3.interscience.wiley.com/journal/122192033/abstract

180.31 Jennifer, T., Kerr, W.C. Energy intake estimates of respondent-measured alcoholic beverages. Alcohol Alcohol. 44(1), 34–41; 2009.

Abstract available online at http://alcalc.oxfordjournals.org/cgi/content/abstract/44/1/34

180.32 Wakabayashi, I. Impact of body weight on the relationship between alcohol intake and blood pressure. Alcohol Alcohol. 44(2), 204–210; 2009.

Abstract available online at http://alcalc.oxfordjournals.org/cgi/content/abstract/44/2/204 C

June 2009 Technical Review No. 180 37 L 180.33 Chanraud-Guillermo, S., Andoh, J., Martelli, C., Artiges, E., Pallier, C., Aubin, H.-J., Martinot, J.-L., Reynaud, M. Imaging of language-related brain regions in detoxified alcoholics. Alcohol. Clin. Exp. Res. 33(4), 1–8; 2009.

Abstract available online at http://www3.interscience.wiley.com/journal/122278094/abstract

180.34 Ikehara, S., Iso, H., Yamagishi, K., Yamamoto, S., Inoue, M., Tsugane, S. Alcohol consumption, social support, and risk of stroke and coronary heart disease among Japanese men: the JPHC study. Alcohol. Clin. Exp. Res. 33(4), 1–8; 2009.

Abstract available online at http://www3.interscience.wiley.com/journal/122268274/abstract

180.35 Osaki, Y., Tanihata, T., Ohida, T., Kanda, H., Suzuki, K., Higuchi, S., Kaneita, Y., Minowa, M., Hayashi, K. Decrease in the prevalence of adolescent alcohol use and its possible causes in Japan: periodical nationwide cross-sectional surveys. Alcohol. Clin. Exp. Res. 33(2), 247–254; 2009.

Abstract available online at http://www3.interscience.wiley.com/journal/121499808/abstract

180.36 Valencia-Martín, J.L., Galán, I., Rodríguez-Artalejo, F. Alcohol and self-rated health in a Mediterranean country: the role of average volume, drinking pattern, and alcohol dependence. Alcohol. Clin. Exp. Res. 33(2), 240–246; 2009.

Abstract available online at http://www3.interscience.wiley.com/journal/121496836/abstract

180.37 Tucker, K.L, Jugdaohsingh, R., Powell, J.J, Qiao, N., Hannan, M.T, Sripanyakorn, S., Cupples, L A., Kiel, D.P Effects of beer, wine, and liquor intakes on bone mineral density in older men and women. Am. J. Clin. Nutr. 89(4), 1188–1196; 2009.

Abstract available online at http://www.ajcn.org/cgi/content/abstract/89/4/1188

180.38 Klatsky, A.L. Invited commentary: Never, or hardly ever? It could make a difference. Am. J. Epidemiol 168(8), 872–875; 2008.

Abstract available online at http://aje.oxfordjournals.org/cgi/content/abstract/168/8/872

38 Technical Review No. 180 June 2009 180.39 Klatsky, A.L. Alcohol, wine, and vascular diseases: an abundance of paradoxes. Am. J. Physiol. Heart Circ. Physiol. 294, 582–583; 2008.

Abstract available online from http://ajpheart.physiology.org/

180.40 Parackav, S.M., Parackav, M.K., Harraway, J.A., Ferguson, E.L. Opinions of non-pregnant New Zealand women aged 16-40 years about the safety of alcohol consumption during pregnancy. Drug Alcohol Rev. 28, 135–141; 2009.

Abstract not available for reproduction.

180.41 Rodríguez-Martos, A., Castellano, Y. Web-based screening and advice for hazardous drinkers: use of a Spanish site. Drug Alcohol Rev. 28, 54–59; 2009.

Abstract not available for reproduction.

180.42 Segal, D.S., Stockwell, T. Low alcohol alternatives: a promising strategy for reducing alcohol related harm. Int. J. Drug Policy 20(2), 183–187; 2009.

Abstract available online from http://www.sciencedirect.com/science/journal/09553959

180.43 Lee, S.J., Sudore, R.L., Williams, B.A., Lindquist, K., Chen, H.L., Covinsky, K.E. Functional limitations, socioeconomic status, and all-cause mortality in moderate alcohol drinkers. J. Am. Geriatr. Soc. Published online 17 March; 2009.

Abstract available online at http://www3.interscience.wiley.com/journal/122265242/abstract

June 2009 Technical Review No. 180 39 L Environmental health

180.44 Green efforts not valued by UK wine consumers – Yalumba case study reveals. Aust. N.Z. Wine Ind. J. 24(1), 39–39; 2009.

A UK-based value chain expert states that consumers in his homeland are not thinking about ‘wine miles’ and sustainability as much as first believed, and perceive Australian wine to be a ‘safe bet’, ‘everyday’ option, not comparable with French or Italian wines for special occasions.

180.45 Energy efficiency and sustainability. Pract. Winery Vineyard Jan/Feb, 6–109; 2009.

This article details the development of a cutting edge wine processing facility in California with a strong commitment to energy efficiency and sustainability.

180.46 Jones, G.V. Global climate change and wine production. Prog. Agric. Vitic. 126(2), 28–39; 2009.

[French] Climate change has the potential to greatly impact nearly every form of agriculture. However, history has shown that the narrow climatic zones for growing winegrapes are especially prone to variations in climate and long-term climate change. While the observed warming over the last fifty years appears to have mostly benefited the quality of wine grown worldwide, projections of future warming at the global, continent, and wine region scale will likely have both a beneficial and detrimental impacts through opening new areas to viticulture and increasing viability, or severely challenging the ability to adequately grow grapes and produce quality wine. Overall, the projected rate and magnitude of future climate change will likely bring about numerous potential impacts for the wine industry, including added pressure on increasingly scarce water supplies, additional changes in grapevine phenological timing, further disruption or alterations of balanced composition and flavor in grapes and wine, regionally- specific changes in varieties grown, necessary shifts in regional wine styles, and spatial changes in viable grape growing regions.

A translation of the above article is available at a charge of $5 per page.

40 Technical Review No. 180 June 2009 180.47 Madigan, A. UK drinkers ‘don’t rate sustainability’. WBM February, 48–49; 2009.

Research published in a report entitled ‘Sustainable value chain analysis: a case study of South Australian wine’ suggests that UK residents are more interested in price, style and colour of the wine than they are in environmental and sustainability issues.

180.48 Ulrich, T. A perfect storm: how winemakers controlled wildfire smoke taint in 2008 juice, must and wine. Wines Vines January, 64–67; 2009.

Imaginative ways of tackling smoke taint alleviated fallout from wildfires fueled by three consecutive dry years along the West Coast of North America. Winemakers Rick Davis and Todd Quigley pioneered a way to reduce smoke taint from the juice and must. The staffs of Memstar North America and Winesecrets developed methods for reducing smoke taint after fermentation.

© Reprinted with permission from Ulrich, T. A perfect storm: how winemakers controlled wildfire smoke taint in 2008 juice, must and wine. Wines Vines January, 64–67; 2009. Copyright 2009 The Hiaring Company.

June 2009 Technical Review No. 180 41 L Viticulture General

180.49 Lamb, D.W. Electrically heated cables protect vines from frost damage at early flowering. Aust. J. Grape Wine Res. 15(1), 79–84; 2009.

Background and Aims: Current methods of frost protection in vineyards involve fans, air heaters or sprinklers; each is limited by environmental constraints or available water. An alternative, all-electrical technique offers growers wider choice to match options with their vineyard operations. This study evaluates the ability of electrical heating cables, wrapped around the vine cordons, to protect inflorescences from frost damage. Methods and Results: Five heating cable treatments in six replicates were applied to a 2-ha block of Sauvignon Blanc in the southern New England Region of Australia. Vines were subjected to a single −3°C frost event in November 2006 when at approximately 30% capfall. Non-heated vines suffered 41% (Control) and 46% (No heat) inflorescence loss. Those subjected to Low heat suffered a 28% loss, Medium-heated vines suffered a 16% loss and High-heated vines suffered a 13% loss. Qualitative scoring of the vines indicated that more than half of the Medium-/High-heated vines suffered no appreciate damage, whereas all non-heated vines suffered some form of potential crop loss or damage. Conclusion: Electrical heating cables of minimum 10 W/m power rating were found to significantly reduce frost damage to inflorescences at 30% capfall. Significance of the Study: At approximately 43 kW/ha, electrical heating cable offers an alternative frost protection method for small vineyards.

© Reprinted with permission from Lamb, D.W. Electrically heated cables protect vines from frost damage at early flowering. Aust. J. Grape Wine Res. 15(1), 79–84; 2009. Copyright 2009 Australian Society of Viticulture and Oenology.

180.50 Mattivi, F., Vrhovsek, U., Masuero, D., Trainotti, D. Differences in the amount and structure of extractable skin and seed tannins amongst red grape varieties. Aust. J. Grape Wine Res. 15(1), 27–35; 2009.

Background and Aims: Red wine is a very rich source of flavanols, consisting of catechins and oligomeric and polymeric proanthocyanidins (PAs). The aim of this study was to investigate the composition of the fraction of flavanols, which is extractable from the grape into the wine. Methods and Results: Using HPLC-DAD-MS analysis carried out before and after thioacidolysis of wine-like extracts obtained from skins and seeds, the flavanol composition of 20 samples derived from Cabernet Sauvignon, Carmenere, Marzemino, Merlot, Pinot Noir, Syrah and Teroldego was determined. Conclusions: It was confirmed that grape extracts are mainly rich in monomers and small oligomers (mean degree of polymerization <8). Grape seed extracts contained three monomers (catechin, epicatechin and epicatechin gallate) and procyanidin oligomers. Grape skin extracts contained four monomers (catechin, epicatechin,

42 Technical Review No. 180 June 2009 gallocatechin and epigallocatechin), procyanidins and prodelphinidins oligomers. Upper and extension units of PAs were constituted mainly of epicatechin units, with the co-presence of catechin and epicatechin gallate in the seed PAs, and of gallocatechin in the case of skin PAs. The terminal units of the grape PAs were a mixture of five compounds, the same found also as monomers. Catechin gallate, gallocatechin gallate and epigallocatechin gallate, which are found in other flavanol-rich, plant-derived foods and beverages, were not present in grape extracts. Significance of the Study: The grape variety determines both the amount and the structure of wine flavanols, leading to differences in the composition, which are likely to play an important role in the nutritional and sensorial properties of the wines.

© Reprinted with permission from Mattivi, F., Vrhovsek, U., Masuero, D., Trainotti, D. Differences in the amount and structure of extractable skin and seed tannins amongst red grape varieties. Aust. J. Grape Wine Res. 15(1), 27–35; 2009. Copyright 2009 Australian Society of Viticulture and Oenology.

180.51 Grace, W., Hayman, P. Understanding heatwaves in South-East Australian wine regions. Aust. N.Z. Grapegrower Winemaker 541, 21–25; 2009.

Of all natural disasters in Australia, heatwaves are the most lethal. This article is the first in a three-part series by SARDI climate applications scientists. The series is designed to increase growers’ understanding of heatwaves in our current and changing climate.

© Reprinted with permission from Grace, W., Hayman, P. Understanding heatwaves in South-East Australian wine regions. Aust. N.Z. Grapegrower Winemaker 541, 21–25; 2009. Copyright 2009 Winetitles Pty Ltd.

180.52 Grace, W., Hayman, P. The mathematics of heatwaves in South-Eastern Australian winegrowing regions. Aust. N.Z. Grapegrower Winemaker 542, 45–49; 2009.

Of all natural disasters in Australia, heatwaves are the most lethal. This article is the second in a three-part series by SARDI climate applications scientists. The series is designed to increase growers’ understanding of heatwaves in our current and changing climate.

© Reprinted with permission from Grace, W., Hayman, P. The mathematics of heatwaves in South-Eastern Australian winegrowing regions. Aust. N.Z. Grapegrower Winemaker 542, 45–49; 2009. Copyright 2009 Winetitles Pty Ltd.

180.53 Zsófi, Z., Gál, L., Szilágyi, Z., Szűcs, E., Marschall, M., Nagy, Z., Bálo, B. Use of stomatal conductance and pre-dawn water potential to classify terroir for the grape variety Kékfrankos. Aust. J. Grape Wine Res. 15(1), 36–47; 2009.

Background and Aims: A 3-year study was carried out in order to evaluate the ecophysiology, yield and quality characteristics of Vitis vinifera L. cv. Kékfrankos (syn. Limberger) at Eger-Nagyeged hill (steep slope) and at Eger-Kőlyuktető (flat) vineyard sites located in the Eger wine region, Hungary. The aim C

June 2009 Technical Review No. 180 43 L of this paper was to analyse the effect of ‘vintage’ and ‘terroir’ on the seasonal changes of Kékfrankos ecophysiology and its possible relationship with yield and wine composition. Methods and Results: Grapevine physiological responses (midday- and pre-dawn water potential, pressure–volume analysis and gas-exchange), growing stages, yield and wine composition of each vineyard were studied. Lower grapevine water supply was detected at Eger-Nagyeged hill in each season due to its steep slope and soil characteristics. Pressure-volume curves indicated that there was no osmotic adjustment in the leaves of this variety. Higher osmotic concentration was measured at turgor loss and full turgor in the leaves of the unstressed vineyard (Eger-Kőlyuktető) presumably due to higher photosynthetic activity. Differences in soil water content of the vineyards resulted in a slightly altered cell wall elasticity. Stomatal conductance, transpiration rate and photosynthetic production per unit leaf area were affected by water availability. Lower yield in Eger-Nagyeged hill was partly associated with decreased photosynthetic production of the canopy. Improved wine quality of Eger-Nagyeged hill was due to moderate water stress which induced higher concentration of anthocyanins and phenolics in the berries. The duration of the phenological stages was dependent on vintage temperature characteristics rather than on vineyard site. Conclusion: There was a close relationship between environmental conditions, Kékfrankos gas-exchange, water relations, yield and wine composition. Water deficit plays an important role in creating a terroir effect, resulting in decreased yield, better sun exposure of leaves and clusters and thus higher concentration of phenolics and anthocyanins. Although quality is mainly influenced by vintage differences, vineyard characteristics are able to buffer unfavourable vintage effects even within a small wine region. Significance of the Study: Stomatal conductance, pre-dawn water potential and climatic data may be reliable parameters for terroir classification, although variety–terroir interactions must always be considered.

© Reprinted with permission from Zsófi, Z., Gál, L., Szilágyi, Z., Szűcs, E., Marschall, M., Nagy, Z., Bálo, B. Use of stomatal conductance and pre-dawn water potential to classify terroir for the grape variety Kékfrankos. Aust. J. Grape Wine Res. 15(1), 36–47; 2009. Copyright 2009 Australian Society of Viticulture and Oenology.

180.54 Hackett, S., Greer, D., Rogiers, S. Avoiding potential heat stress. Aust. N.Z. Grapegrower Winemaker 541, 14–15; 2009.

Heat stress limits photosynthesis, increases respiration and diverts carbohydrates away from ripening bunches. This leads to lower sugar accumulation, reduced acid levels and colour in berries. Several measures can limit the impact of increasing air temperature on overall vine function: • Water vines prior to any heat stress – this is even more critical with flood/furrow irrigated vineyards. • Flood-irrigated vineyards should be watered at least 24–48 hours prior to forecast hot spell • Canopies that offer dappled or mottled sunlight are recommended over those that leave fruit over or under exposed.

44 Technical Review No. 180 June 2009 180.55 Russell, A. Australian Wine Environmental Stewardship demonstrates commitment to sustainability. Aust. N.Z. Wine Ind. J. 24(1), 59–59; 2009.

This article provides an insight into Australian Wine Environmental Stewardship which is the wine sector’s voluntary environmental certification scheme.

© Reprinted with permission from Russell, A. Australian Wine Environmental Stewardship demonstrates commitment to sustainability. Aust. N.Z. Wine Ind. J. 24(1), 59–59; 2009. Copyright 2009 Winetitles Pty Ltd.

180.56 Smith, M. $1.8m research program sets tone for new regional node. Aust. Vitic. 13(1), 60–62; 2009.

The AWRI recently launched its first regional node at the Tasmanian Institute of Agricultural Research, led by Dr Bob Dambergs.

180.57 Viticulture durable en Champagne: guide pratique 2009. Le Vigneron Champenois (Special Supplement), 1–204; 2009.

[French] Abstract is not available for publication. Note that due to the size of this publication and copyright restrictions, only copies of selected chapters may be requested at any given time. Please contact the AWRI Library for further information.

A translation of the above article is available at a charge of $5 per page. 180.58 Castillo-Muñoz, N., Gómez-Alonso, S., García-Romero, E., Gómez, M.V., Velders, A.H., Hermosín-Gutiérrez, I. Flavonol 3-O-glycosides series of Vitis vinifera cv. Petit Verdot red wine grapes. J. Agric. Food Chem. 57(1), 209–219; 2009.

To gain knowledge of the characteristic flavonol 3-O-glycosides of red grape Vitis vinifera varieties, we isolated the flavonol fraction from V. vinifera cv. Petit Verdot grape skins by solid-phase extraction using a combination of reverse-phase and ion-exchanging materials. This procedure allowed us to separate a fraction of anthocyanin-free flavonol 3-O-glycosides that was further split into neutral and acidic subfractions, thus facilitating flavonol identification. By means of semipreparative reverse- phase high-performance liquid chromatography, we isolated several of these flavonol 3-O-glycosides for structural elucidation. The identification of different flavonolO 3- -glycosides was based on liquid chromatography−diode array detection−electrospray ionization−tandem mass spectrometry and C

June 2009 Technical Review No. 180 45 L NMR data when available. The results suggest that red grape flavonol O3- -glycosides comprise three different complete series, according to the nature of the sugar moiety linked to the C-3 position. The 3-O-glucosides were the main derivative of the six possible flavonol aglycones (kaempferol, quercetin, isorhamnetin, myricetin, laricitrin, and syringetin), whereas the 3-O-galactoside derivatives were found as minor compounds for all of the flavonol aglycones. The 3-O-glucuronides are the third kind of red grape flavonol derivatives and normally account as minor compounds for all of the flavonol aglycones, with the exception of quercetin 3-O-glucuronide, which was as abundant as quercetin 3-O-glucoside. In addition, the presence of quercetin 3-O-(6′′-rhamnosyl)-glucoside (rutin) was also detected as a trace compound in the skins of Petit Verdot grapes.

© Reprinted with permission from Castillo-Muñoz, N., Gómez-Alonso, S., García-Romero, E., Gómez, M.V., Velders, A.H., Hermosín-Gutiérrez, I. Flavonol 3-o-glycosides series of Vitis vinifera cv. Petit Verdot red wine grapes. J. Agric. Food Chem. 57(1), 209–219; 2009. Copyright 2009 American Chemical Society.

180.59 Chira, K., Schmauch, G., Saucier, C., Fabre, S., Teissedre, P.-L. Grape variety effect on proanthocyanidin composition and sensory perception of skin and seed tannin extracts from Bordeaux wine grapes (Cabernet Sauvignon and Merlot) for two consecutive vintages (2006 and 2007). J. Agric. Food Chem. 57(2), 545–553; 2009.

Grape variety [Cabernet Sauvignon (CS) and Merlot (M)] effect on the proanthocyanidin composition and sensory perception of wine grapes from Bordeaux vineyards for two successive vintages (2006 and 2007) is reported. The flavan-3-ol monomers [(+)-catechin = C, (−)-epicatechin = EC, (−)-epicatechin-O-gallatte = ECG] and the proanthocyanidin oligomers [dimers B1, B2, B3, and B4 and trimer Cat-Cat-Epi (T)] in grape seed and skin tannin extracts were identified and quantified at harvest. Proanthocyanidin subunit compositions, percentage of galloylation (%G), and percentage of prodelphinidins (%P) as well as mean degree of polymerization (mDP) of the proanthocyanidin fraction were determined. Sensory analysis concerning the astringency and bitterness intensity of the proanthocyanidins of skin and seed tannin extracts was also performed. The results showed that proanthocyanidin composition can be greatly affected by grape variety. For both vintages between CS and M, significant differences were found on mDPp ( < 0.05) in seed tannin extracts, whereas in skin tannin extracts, significant differences were observed for %G and %P (p < 0.05). Sensory analysis showed that grape variety influenced neither astringency nor bitterness intensity perception for both skin and seed tannin extracts for the two successive vintages studied. A positive correlation was found between astringency intensity, mDP, and B3 content in skin tannin extracts.

© Reprinted with permission from Chira, K., Schmauch, G., Saucier, C., Fabre, S., Teissedre, P.-L. Grape variety effect on proanthocyanidin composition and sensory perception of skin and seed tannin extracts from Bordeaux wine grapes (Cabernet Sauvignon and Merlot) for two consecutive vintages (2006 and 2007). J. Agric. Food Chem. 57(2), 545–553; 2009. Copyright 2009 American Chemical Society.

46 Technical Review No. 180 June 2009 180.60 Huang, Z., Wang, B., Williams, P., Pace, R.D. Identification of anthocyanins in muscadine grapes with HPLC-ESI-MS. LWT 42(4), 819–824; 2009.

Abstract available online from http://www.sciencedirect.com/science/journal/00236438

180.61 Stoll, M., Schwarz, H.-P., Gaubatz, B., Müller, R. Global viticulture: quality management systems and traceability. Mitt. Klosterneuburg Rebe Wein 58, 75–81; 2008.

[German] Abstract not available for reproduction

A translation of the above article is available at a charge of $5 per page.

180.62 Morabito, L. Caring for country: post-Kyoto responses to greenhouse emissions from agriculture. National Environ. Law Rev. 3, 34–41; 2008.

This paper examines whether and how effective current and pending law and policy attempts are or shall be at adapting to or mitigating the impacts of climate change in the agricultural sector.

© Reprinted with permission from Morabito, L. Caring for country: post-Kyoto responses to greenhouse emissions from agriculture. National Environ. Law Rev. 3, 34–41; 2008. Copyright 2008 National Environmental Law Association.

180.63 Actualités viticoles. Rev. Suisse Vitic. Arboric. Hortic. 41(1), 61–78; 2009.

[French] A collection of articles on viticultural news

© Reprinted with permission from Actualités viticoles. Rev. Suisse Vitic. Arboric. Hortic. 41(1), 61–78; 2009. Copyright 2009 Association pour la mise en valeur des travaux de la recherche agronomique.

A translation of the above article is available at a charge of $5 per page.

180.64 Le guide viti d’ACW. Rev. Suisse Vitic. Arboric. Hortic. 41(1), 12–58; 2009.

[French] This special reports presents a comprehensive guide to viticulture

A translation of the above article is available at a charge of $5 per page. C

June 2009 Technical Review No. 180 47 L 180.65 Stefano, R.D., Mattivi, F., Caburazzi, M., Giustini, E., Bonifazi, L. Evolution of phenolic composition of Sagrantino grapes during maturation. Riv. Vitic. Enol. 1, 39–61; 2008.

[Italian] During the vintages 2003–2006 has been followed the evolution of the total and extractable as well as of the monomeric phenolic compounds of the skins and seeds of the Sagrantino grape variety. The purpose was to acquire information about the optimal date for the harvest as well as about the techniques of winemaking directed to express the characters of this variety to the best. It is confirmed that the skins and the seeds of the grape of the cultivar in question possess remarkable amount of tannins and a middle-high amount in anthocyanins. Around halves of these compounds can be retained in the must at the end of the alcoholic fermentation. Despite the sugars’ accumulation continue in the grape up to the first 15 days of October, reaching very elevated values, the synthesis of the anthocyanins, in the actual climatic conditions, seems to reach a maximum one month in advance. The profiles of the anthocyanins and the hydrohycinnamoyl tartaric acids show a good stability. Among the anthocyanins prevail the molecules trisubstituted to the lateral ring, but also the percentages of the disubstituted ones, the peonidin in particular, result appreciable. More small, instead, are the percentages of the acilated anthocyanins. Among the hydroxycinnamoyl tartaric acids prevails the caftaric acid, among the flavonols the glycosilated forms of the quercetin. The amount of the myricetin glucoside, nevertheless, results similar to that of the quercetin glucoside. Notable variations have been found in the profile of the flavonols that have been attributed, on the base of knowledges acquired in early experiences, to the environmental influences. The grapes of the variety in question, are endowed with a notable amount of PPO that, nevertheless, can be kept under control avoiding the contact with the oxygen, in the laboratory during the phase of extraction of the polyphenols or, in the wine cellar when the fermentation is not begun yet. The results of this work encourage experiences of winemaking of grapes harvested before the physiological maturation, to avoid a too elevated alcoholic content in the resulting wines, and the employment of techniques of vinification and maturation of wines able to contain the astringency and to stabilize the color of Sagrantino wines.

© Reprinted with permission from Stefano, R.D., Mattivi, F., Caburazzi, M., Giustini, E., Bonifazi, L. Evolution of phenolic composition of Sagrantino grapes during maturation. Riv. Vitic. Enol. 1, 39–61; 2008. Copyright 2008 Istituto Sperimentale per la Viticoltura e dell’Istituto Sperimentale per l’Enologia.

A translation of the above article is available at a charge of $5 per page.

48 Technical Review No. 180 June 2009 180.66 Chervin, C., Tira-Umphon, A., Chatelet, P., Jauneau, A., Boss, P.K., Tesniere, C. Ethylene and other stimuli affect expression of the UDP glucose-flavonoid 3-0-glucosyltransferase in a non-climacteric fruit. Vitis 48(1), 11–16; 2009.

The UDP glucose-flavonoid 3-0-glucoslyltransferase (UFGT) is a key enzyme for biosynthesis and stability of anthocyanin pigments of red grapes. Understanding factors affecting expression of this enzyme is thus important for the control of grape colour. A 1640 bp promoter region of the grapevine ufgt gene was cloned and sequenced. Sequence analysis revealed seven putative ethylene-responsive cis- elements and others related to three major signals known to induce anthocyanin accumulation in plant tissues: light, sugar, and abscisic acid. In order to evaluate the ability of ethylene and other signals to drive expression from the ufgt promoter, we ran transient expression experiments using an anthocyanin-rich grape cell culture, with very low green auto-fluorescence. After biolistic bombardment, the cells were treated with various combinations of the four signals on gfp expression (green fluorescent protein). The comparison of fluorescent light intensity in cells subjected to the various treatments showed that ethylene better stimulates expression of the ufgt promoter in the dark than under light. In addition, results showed that there may be a positive interaction between ethylene and abscisic acid. This system, a promoter of interest driving the gfp expression in cells with low auto-fluorescence, may be a good tool for studies about synergistic or antagonist roles of transcription factors. Moreover, treatment of grape berries with a specific inhibitor of ethylene receptors (1-methylcyclopropene) inhibited ufgt mRNA accumulation. This confirms that the ethylene signal is likely a regulator of grape UFGT expression in a non-climacteric fruit.

© Reprinted with permission from Chervin, C., Tira-Umphon, A., Chatelet, P., Jauneau, A., Boss, P.K., Tesniere, C. Ethylene and other stimuli affect expression of the UDP glucose-flavonoid 3-0-glucosyltransferase in a non-climacteric fruit. Vitis 48(1), 11–16; 2009. Copyright 2009 Institut für Rebenzüchtung Geilweilerhof der Bundesanstalt für Züchtungsforschung an Kulturpflanzen.

180.67 Intrigilolo, D.S., Lakso, A.N. Berry abscission is related to berry growth in Vitis labruscana ‘Concord’ and Vitis vinifera ‘Riesling’. Vitis 48(1), 53–54; 2009.

Results presented in this paper appear to be the first evidence that berry abscission in grapevines can be related to the berry growth rate relative to fastest growing berries in a vine.

© Reproduced with permission from Intrigilolo, D.S., Lakso, A.N. Berry abscission is related to berry growth in Vitis labruscana ‘Concord’ and Vitis vinifera ‘Riesling’. Vitis 48(1), 53–54; 2009. Copyright 2009 Institut für Rebenzüchtung Geilweilerhof der Bundesanstalt für Züchtungsforschung an Kulturpflanzen.

June 2009 Technical Review No. 180 49 L Vine propagation and improvement

180.68 Pan, Q.-H., Cao, P., Duan, C.-Q. Comparison of enzymes involved in sugar metabolism from Shang-24 (Vinifera quinguangularis) and Cabernet Sauvignon (Vinifera vinifera) at veraison. Aust. J. Grape Wine Res. 15(1), 9–17; 2009.

Background and Aims: Sugar is a main contributor to the quality of grape berries, but little is known about the characteristics of sugar metabolism in Chinese wild grapes. Here, enzymes related to sugar metabolism were investigated in berries of both Shang-24 (Vitis quinguangularis Rehd), a wild grape native to China, and Cabernet Sauvignon (V. vinifera L.). Methods and Results: Analyses using high performance liquid chromatography and spectrophotometer showed that Shang-24 contained lower levels of glucose and fructose, compared with Cabernet Sauvignon, but had higher activities of enzymes related to sugar hydrolysis, particularly soluble acid invertase (SAI) and β-amylase. Analyses of enzyme kinetics, enzyme-linked immunosorbent assay and Western blot revealed that SAI and β-amylase in Shang-24 had low Km values and that high levels of both enzymes were present. Furthermore, a novel peptide of SAI of 105 kDa was detected in Shang-24 along with a peptide of 60 kDa that also was present in Cabernet Sauvignon. Conclusions: It is thus suggested that biochemical characteristics of SAI and β-amylase in Shang-24 differ from those in Cabernet Sauvignon, and the novel peptide may be related to high activity of SAI in Shang-24. Significance of the Study:These data provide an essential basis for further study of the genetic regulation of sugar and its metabolism in grape berries.

© Reprinted with permission from Pan, Q.-H., Cao, P., Duan, C.-Q. Comparison of enzymes involved in sugar metabolism from Shang-24 (Vinifera quinguangularis) and Cabernet Sauvignon (Vinifera vinifera) at veraison. Aust. J. Grape Wine Res. 15(1), 9–17; 2009. Copyright 2009 Australian Society of Viticulture and Oenology.

180.69 Revilla, E., García-Beneytez, E., Cabello, F. Anthocyanin fingerprint of clones of Tempranillo grapes and wines made with them. Aust. J. Grape Wine Res. 15(1), 70–78; 2009.

Background and Aims: Different clones with distinctive enological characteristics have been identified in many grape cultivars, but data on differences in anthocyanin composition of clones of the same cultivar are scarce. Thus, it has been considered of interest to check changes in the anthocyanin fingerprint of six different clones of Tempranillo grapes grown in the same vineyard, and of wines made with them, over three consecutive years. Methods and Results: Data were submitted to different statistical procedures. Despite slight differences in the anthocyanin fingerprint of some clones (relative content of different anthocyanins analysed), variations from year to year were more important than differences in the anthocyanin profile of the clones considered. This fact was also observed when the content (mg/kg grapes) of those molecules was considered. Moreover, Tempranillo wines made with different clones could be classified by discriminant analysis, using the anthocyanin fingerprint or the levels (mg/L wine)

50 Technical Review No. 180 June 2009 of several anthocyanins as predictor variables, and the year grapes were collected as a classification factor. Conclusions: The anthocyanin fingerprint of six clones of Tempranillo grapes grown in the same vineyard and that of wines made with them over three consecutive years was affected mostly by weather conditions, despite slight differences in the anthocyanin fingerprint of some clones.Significance of the Study: This is the first report on the anthocyanin composition of different clones of Tempranillo grapes and of wines made with them, and indicates that anthocyanin fingerprint of Tempranillo wines depends mainly on agroclimatic factors, and not on genetic differences among clones.

© Reprinted with permission from Revilla, E., García-Beneytez, E., Cabello, F. Anthocyanin fingerprint of clones of Tempranillo grapes and wines made with them. Aust. J. Grape Wine Res. 15(1), 70–78; 2009. Copyright 2009 Australian Society of Viticulture and Oenology.

180.70 Sweet, N.L., Wolpert, J.A. Clonal diversity of Zinfandel. Pract. Winery Vineyard Jan/Feb, 90–105; 2009.

This article details the genetic diversity of Zinfandel and presents observations of the variety in California, Croatia and Italy.

180.71 Calò, A., Masi, G., Tarricone, L., Costacurta, A., Meneghetti, S., Crespan, M., Carraro, R. Search for Primitivo (V. vinifera L.) variability in Apulia. Riv. Vitic. Enol. 4, 3–13; 2007.

[Italian] In ancient vineyards sited in typical cultivation areas (Taranto province, Gioia del Colle) of Primitivo new researches have been done to evaluate its genetic variability. Overall based on bunch (shape, size, density) and berry (size, colour of skin) characteristics 46 vines have been identified. Five typologies have been identified by means of ampelographic, phyllometric and DNA (SSR, AFLP, M-AFLP) analyses; the present work report their main features.

© Reprinted with permission from Calò, A., Masi, G., Tarricone, L., Costacurta, A., Meneghetti, S., Crespan, M., Carraro, R. Search for Primitivo (V. vinifera L.) variability in Apulia. Riv. Vitic. Enol. 4, 3–13; 2007. Copyright 2007 Istituto Sperimentale per la Viticoltura e dell’Istituto Sperimentale per l’Enologia.

A translation of the above article is available at a charge of $5 per page.

June 2009 Technical Review No. 180 51 L 180.72 Laiadi, Z., Bentchikou, M.M., Bravo, G., Cabello, F., Martínez-Zapater, J.M. Molecular identification and genetic relationships of Algerian grapevine cultivars maintained at the germplasm collection of Skikda (Algeria). Vitis 48(1), 25–32; 2009.

We have used nuclear and chloroplast microsatellite markers to characterize a collection of 36 Algerian grapevine (Vitis vinifera L.) accessions maintained at the germplasm collection of Skikda (Algeria). The genetic diversity observed within the collection was comparable to what has been described for cultivated accessions of grapevine. Moreover, chlorotype C, associated to eastern accessions and highly frequent among table grape cultivars, was overrepresented in the collection. Genotype comparisons among the accessions and published cultivar genotypes identified a few synonyms within the collection as well as putative synonyms for Algerian accessions such as ‘Aïn el Kelb’, ‘Ahmar Mechtras’, ‘Ahmar de Mascara’ or ‘Bouni’ among cultivars grown in both Eastern and Western areas of the Mediterranean basin. Furthermore, the study of genetic relationships among the Algerian accessions suggests the existence of close relatedness within some groups of cultivars that could have been originated by spontaneous hybridization and seed propagation.

© Reprinted with permission from Laiadi, Z., Bentchikou, M.M., Bravo, G., Cabello, F., Martínez-Zapater, J.M. Molecular identification and genetic relationships of Algerian grapevine cultivars maintained at the germplasm collection of Skikda (Algeria). Vitis 48(1), 25–32; 2009. Copyright 2009 Institut für Rebenzüchtung Geilweilerhof der Bundesanstalt für Züchtungsforschung an Kulturpflanzen.

52 Technical Review No. 180 June 2009 Pests and diseases

180.73 Weckert, M. Infection of grapevines with Pseudomonas syringae in a frost-prone region. Aust. Vitic. 13(1), 55–55; 2009.

The bacterial pathogen, Pseudomonas syringae, has been isolated from diseased shoots, leaves, bunch rachises and berries in one New South Wales cool-climate region. Whereas this is a common pathogen of many horticultural crops it is the first time it has caused berry and bunch loss of Australian grapevines.

180.74 Doker, A., Kubiak, R. Stem application of metalaxyl for the protection of Vitis vinifera L. (‘Riesling’) leaves and grapes against downy mildew (Plasmopara viticola). Vitis 48(1), 43–48; 2009.

The direct application of plant protective agents into tree xylem is an ecologically sound method of plant protection, which has already been used for trees in urban environements. In order to make this system viable for grapevines (Vitis), the effectiveness of the protective system must be ensured. In the first experiment, the effect of the fungicide agents dimethomorph, fosetyl-al, iprovalicarb and metalaxyl applied to the stem of field-grown grapevines was investigated. As a result injection experiments using non-formulated metalaxyl showed the desired protective effects against downy mildew (Plasmopara viticola). In the second experiment, non-formulated metalaxyl was applied several times in succession over a period of several weeks to the xylem of test grapevines using an injection system, affixed long-term to the vine stems. Grapevines sprayed with formulated metalaxyl (Fonganil Gold®) enabled the methods to be compared. The efficiency factors with regard to the control of downy mildew in leaves and grapes were very similar in both approaches, with values of practical relevance of over 70%.

© Reprinted with permission from Doker, A., Kubiak, R. Stem application of metalaxyl for the protection of Vitis vinifera L. (‘Riesling’) leaves and grapes against downy mildew (Plasmopara viticola). Vitis 48(1), 43–48; 2009. Copyright 2009 Institut für Rebenzüchtung Geilweilerhof der Bundesanstalt für Züchtungsforschung an Kulturpflanzen.

June 2009 Technical Review No. 180 53 L Nutrition, soil and water

180.75 Toselli, M., Baldi, E., Marcolini, G., Malaguti, D., Quartieri, M., Sorrenti, G., Marangoni, B. Response of potted grapevines to increasing soil copper concentration. Aust. J. Grape Wine Res. 15(1), 85–92; 2009.

Background and Aims: Copper accumulation in soil may promote phytotoxicity in grapevines. Nutritional implications of potted vines to increasing concentrations of copper (Cu) in either clay loam soil or clay loam soil mixed with 85% sand were tested on Vitis vinifera (L.) cv Sangiovese and crop toxicity threshold and symptoms determined. Methods and Results: Soils were mixed at planting with Cu at the rates (mg Cu/kg) of 0 (control, native soil Cu only), 50, 100, 200, 400, 600, 800 and 1000, and non-bearing vines were grown in these for two seasons. Reduction of root growth was observed after addition of ≥400 mg Cu/kg to both soils; reduction of shoot growth, leaf number and chlorosis of leaf edges were detected only in sand-enriched soil. Root Cu concentration increased in response to soil Cu addition. Unlike that of leaf Cu and N, the amount of P and Fe (in both soils) and Mg and Ca (in sand-enriched soil only) were reduced by soil Cu. Conclusion: Vines grown in sand-enriched soil tolerated lower concentrations of Cu than in clay loam soil, probably because of the lower nutritional status and the higher root Cu concentration. Significance of the Study: Results provide information on the concentration of soil Cu that grapevine can tolerate and on the nutrients involved in the response to toxic levels of soil Cu in clay loam and sandy clay loam soils.

© Reprinted with permission from Toselli, M., Baldi, E., Marcolini, G., Malaguti, D., Quartieri, M., Sorrenti, G., Marangoni, B. Response of potted grapevines to increasing soil copper concentration. Aust. J. Grape Wine Res. 15(1), 85–92; 2009. Copyright 2009 Australian Society of Viticulture and Oenology.

180.76 Chalmers, Y. Irrigation management options during veraison. Aust. Vitic. 13(1), 22–25; 2009.

This article presents advice on managing irrigation during the period of veraison to harvest including vine care during heatwaves.

180.77 Hoare, T. Problem weeds in Australian vineyards. Aust. Vitic. 13(1), 67–71; 2009.

This article provides advice on how to control problem weeds in vineyards.

54 Technical Review No. 180 June 2009 180.78 Logan, S. Impact of low irrigation goes on trial. Aust. Vitic. 13(1), 34–35; 2009.

The effects of low irrigation on vines and how they respond when normal irrigation levels are resumed is being assessed in trials taking place in South Australia’s Riverland and Langhorne Creek.

180.79 Imre, S.P., Mauk, J.L., Bell, S., Dougherty, A. Correlations among ground penetrating radar, electromagnetic induction and vine trunk circumference data: towards quantifying terroir in New Zealand Pinot Noir vineyards. Prog. Agric. Vitic. 126(1), 8–11; 2009.

Variations in grapevine vigour and fruit quality commonly occur within several meters, which may reflect small scale soil variations. We conducted ground penetrating radar (GPR) and electromagnetic (EM) surveys in five Pinot Noir vineyards on different soil types in the South Island of New Zealand to help assess subsurface-variability. We also measured vine trunk circumferences in these vineyards as an indication of vine vigour. Although the geophysical results must be correlated with soil surveys in each vineyard, these results suggest that geophysical surveys can be used to rapidly and cost-effectively map local variations in soils, which in turn influence vine vigour.

© Reprinted with permission from Imre, S.P., Mauk, J.L., Bell, S., Dougherty, A. Correlations among ground penetrating radar, electromagnetic induction and vine trunk circumference data: towards quantifying terroir in New Zealand Pinot Noir vineyards. Prog. Agric. Vitic. 126(1), 8–11; 2009. Copyright 2009 Sté Le Progrès Agricole et Viticole.

180.80 Rodriguez Lovelle, B., Trambouze, W., Jacquet, O. Evaluation of the vine growth status by the ‘shoot tip method’. Prog. Agric. Vitic. 126(4), 77–88; 2009.

[French] The vine growth integrates a global behaviour related to the water and nitrogen consumption of the plants. The authors describe and propose the ‘shoot tip method’ to evaluate the general status of the vine growth. It’s a simple non destructive field method based on the observation of the shoot tips, classifying them into 3 categories depending on their growth status. This method can discriminate environmental conditions (climate, soil), vine material, agricultural practices (irrigation, nitrogen fertilization, topping) and can also be an efficient tool to select plots for optimising wine-making. These applications of the method are shown by numerous examples where a good link with the water deficit status appears.

© Reprinted with permission from Rodriguez Lovelle, B., Trambouze, W., Jacquet, O. Evaluation of the vine growth status by the ‘shoot tip method’. Prog. Agric. Vitic. 126(4), 77–88; 2009. Copyright 2009 Sté Le Progrès Agricole et Viticole.

A translation of the above article is available at a charge of $5 per page. C

June 2009 Technical Review No. 180 55 L 180.81 Chacón, J.L., García, E., Martínez, J., Romero, R., Gómez, S. Impact of the vine water status on the berry and seed phenolic composition of ‘Merlot’ (Vitis vinifera L.) cultivated in a warm climate: consequence for the style of wine. Vitis 48(1), 7–9; 2009.

During 2005 and 2006 four irrigation treatments were assayed in a vineyard growing ‘Merlot’ grapes located in a warm climate region. The treatments were kept for two years and the wine was produced the second year so that the response of the wines to water constraint was consistent. The phenolic parameters of the wines were analysed. The phenolic composition of the seeds was studied for both years and more significant differences were observed in the second. The results showed that when the deficiency increased, so did the concentration of total polyphenols, flavan-3-ols and tannins in the seeds. Pre-dawn leaf water constraint integrals between 20 and 24 Mpa as opposed to levels of 9 to 14 caused statistically significant increases in total polyphenols, flavan-3-ols and the colour index of the wine. These differences were manifested in sensory terms by significant intensification of the colour and body of the wines.

© Reprinted with permission from Chacon, J.L., Garcia, E., Martinez, J., Romero, R., Gomez, S. Impact of the vine water status on the berry and seed phenolic composition of ‘Merlot’ (Vitis vinifera L.) cultivated in a warm climate: consequence for the style of wine. Vitis 48(1), 7–9; 2009. Copyright 2009 Institut für Rebenzüchtung Geilweilerhof der Bundesanstalt für Züchtungsforschung an Kulturpflanzen.

Vineyard canopy management

180.82 Considine, J.A., Cass, G. Site, vine state and responsiveness to the application of growth regulator fruitsetting agents. Aust. J. Grape Wine Res. 15(1), 48–58; 2009.

Background and Aims: This study was initiated to investigate local problems in obtaining consistent fruit-setting responses to a recommended treatment combination of gibberellic acid (GA3) and (2-chloroethyl)-trimethyl ammonium chloride (CCC), with vineyard managers returning to more traditional methods of either cincturing or applying 4-chlorophenoxy acetic acid (4-CPA). Methods and Results: Five vineyard study sites located in the Chittering–Bindoon region of Western Australia were characterised by multivariate analysis using measures of vegetative and reproductive biomass. Two experiments were carried out in the vineyard to compare responses to combinations of GA3 and CCC. 4-CPA was used as an industry control. Bunch number was used as a novel covariate to adjust responses to individual vine and site factors. Berry volume increased in all vines and sites treated with GA3, irrespective of timing, but dry matter yield increased only in the youngest vineyards. The only site to show a significant response to CCC application was that with the highest vegetative biomass.Conclusions: We conclude that site and management factors rather than growth regulator type, concentration or timing determined yield responsiveness (sugar production). Significance of the Study: This study demonstrates

56 Technical Review No. 180 June 2009 a strong physiological and environmental effect on response to growth regulator application, reinforcing the importance of developing site-specific management practices. It shows how multivariate techniques may be used to characterise and compare vineyards, and also, how analysis of covariance using a new parameter, bunch number, may be used to enhance statistical of analysis of field experiments.

© Reprinted with permission from Considine, J.A., Cass, G. Site, vine state and responsiveness to the application of growth regulator fruitsetting agents. Aust. J. Grape Wine Res. 15(1), 48–58; 2009. Copyright 2009 Australian Society of Viticulture and Oenology.

180.83 Smart, R. Shoot-positioning made easy. Aust. N.Z. Wine Ind. J. 24(1), 6–8; 2009.

Shoot-positioning has become common practice in vineyards around Australia, but how often is it being done correctly? In this article, the author gives a practical account of shoot-positioning to help producers understand how to carry out the task in a timely and cost-effect manner.

180.84 Pickering, A.H., Warrington, I.J., Woolley, D.J. The impacts of root-pruning on early and late bunch stem necrosis. Aust. Vitic. 13(1), 51–52; 2009.

This article discusses some studies which examine the causes of early bunch stem necrosis and bunch stem necrosis and looks at root pruning as a management tool.

© Reprinted with permission from Pickering, A.H., Warrington, I.J., Woolley, D.J. The impacts of root-pruning on early and late bunch stem necrosis. Aust. Vitic. 13(1), 51–52; 2009. Copyright 2009 Winetitles Pty Ltd.

June 2009 Technical Review No. 180 57 L 180.85 Ferrer, M., Gonzalez Neves, G., Camussi, G., Echeverria, G. Effect of cluster thinning at fruit set and veraison, over productive, vegetative and enological parameters in (Vitis vinifera L.) cv. Tannat. Prog. Agric. Vitic. 126(1), 12–17; 2009.

[French] The clusters thinning effect on productive, vegetative and enological parameters have been studied on Tannat cultivar, for six years (1994-1999) in commercial vineyards of the principal winegrowing region of Uruguay. This practice, done at berry set or veraison, with a 50% in relation to the control, has provoked a diminution on yield, that it hasn’t been proportional to its intensity. Clusters thinning done at clusters set leads to a higher production of pruning wood The Ravaz Index values indicated that clusters thinning treatments allowed to get more equilibrated plants on productive/ vegetative plan, in relation to the control. Clusters thinning done at cluster set has provoked berry size augmentation, but correlations among berry size and wine quality parameters couldn’t be established. Wine from plants clusters thinned at berry set had higher quality than the others, with some differences according to the year.

© Reprinted with permission from Ferrer, M., Gonzalez Neves, G., Camussi, G., Echeverria, G. Effect of cluster thinning at fruit set and veraison, over productive, vegetative and enological parameters in (Vitis vinifera L.) cv. Tannat. Prog. Agric. Vitic. 126(1), 12–17; 2009. Copyright 2009 Sté Le Progrès Agricole et Viticole.

A translation of the above article is available at a charge of $5 per page.

180.86 Intrigliolo, D.S., Lakso, A.N., Centinari, M. Effects of the whole vine versus single shoot-crop level on fruit growth in Vitis labruscana ‘Concord’. Vitis 48(1), 1–5; 2009.

The fruit growth response to the whole vine and single shoot crop level was studied inVitis labruscana ‘Concord’ grown in the North-Eastern United States. In vines thinned to lower and higher yields (equivalent to 12 and 21 t·ha–1), different number of clusters per shoot were retained after cluster thinning one week after set. Results showed that the seasonal accumulation of berry dry weight, fruit fresh weight, and the berry total soluble solids at harvest were only affected by the whole vine crop level. This suggests that under the conditions of this experiment shoots are not autonomous in terms of carbon partitioning to the fruit. Hence, crop level effects on fruit development can be considered and modelled on a whole vine basis.

© Reprinted with permission from Intrigliolo, D.S., Lakso, A.N., Centinari, M. Effects of the whole vine versus single shoot-crop level on fruit growth in Vitis labruscana ‘Concord’. Vitis 48(1), 1–5; 2009. Copyright 2009 Institut für Rebenzüchtung Geilweilerhof der Bundesanstalt für Züchtungsforschung an Kulturpflanzen.

58 Technical Review No. 180 June 2009 AWRI publications

1120 Cordente, A.G., Heinrich, A., Pretorius, I.S., Swiegers, J.H. Isolation of sulfite reductase variants of a commercial wine yeast with significantly reduced hydrogen sulfide production. FEMS Yeast Res. 9(3), 446–459; 2009.

The production of hydrogen sulfide (H2S) during fermentation is a common and significant problem in the global wine industry as it imparts undesirable off-flavors at low concentrations. The yeast Saccharomyces cerevisiae plays a crucial role in the production of volatile sulfur compounds in wine. In this respect, H2S is a necessary intermediate in the assimilation of sulfur by yeast through the sulfate reduction sequence with the key enzyme being sulfite reductase. In this study, we used a classical mutagenesis method to develop and isolate a series of strains, derived from a commercial diploid wine yeast (PDM), which showed a drastic reduction in H2S production in both synthetic and grape juice fermentations. Specific mutations in the MET10 and MET5 genes, which encode the catalytic α- and β-subunits of the sulfite reductase enzyme, respectively, were identified in six of the isolated strains.

Fermentations with these strains indicated that, in comparison with the parent strain, H2S production was reduced by 50–99%, depending on the strain. Further analysis of the wines made with the selected strains indicated that basic chemical parameters were similar to the parent strain except for total sulfite production, which was much higher in some of the mutant strains.

© Reprinted with permission from Cordente, A.G., Heinrich, A., Pretorius, I.S., Swiegers, J.H. Isolation of sulfite reductase variants of a commercial wine yeast with significantly reduced hydrogen sulfide production. FEMS Yeast Res. 9(3), 446–459; 2009. Copyright 2009 Federation of European Microbiological Societies.

1121 Ugliano, M., Fedrizzi, B., Siebert, T., Travis, B., Magno, F., Versini, G., Henschke, P.A. Effect of nitrogen supplementation and Saccharomyces species on hydrogen sulfide and other volatile sulfur compounds in Shiraz fermentation and wine. J. Agric. Food Chem. DOI:10.1021/ jf8037693, 1–8; 2009.

A Shiraz must with low yeast assimilable nitrogen (YAN) was supplemented with two increasing concentrations of diammonium phosphate (DAP) and fermented with one Saccharomyces cerevisiae and one Saccharomyces bayanus strain, with maceration on grape skins. Hydrogen sulfide (H2S) was monitored throughout fermentation, and a total of 16 volatile sulfur compounds (VSCs) were quantified in the finished wines. For the S. cerevisiae yeast strain, addition of DAP to a final YAN of 250 or 400 mg/L resulted in an increased formation of H2S compared to nonsupplemented fermentations (100 mg/L

YAN). For this yeast, DAP-supplemented fermentations also showed prolonged formation of H2S into the later stage of fermentation, which was associated with increased H2S in the final wines. TheS. bayanus strain showed a different H2S production profile, in which production was inversely correlated to initial C

June 2009 Technical Review No. 180 59 L YAN. No correlation was found between total H2S produced by either yeast during fermentation and H2S concentration in the final wines. For both yeasts, DAP supplementation yielded higher concentrations of organic VSCs in the finished wines, including sulfides, disulfides, mercaptans, and mercaptoesters. PCA analysis indicated that nitrogen supplementation before fermentation determined a much clearer distinction between the VSC profiles of the two yeasts compared to non-supplemented fermentations. These results raise questions concerning the widespread use of DAP in the management of low YAN fermentations with respect to the formation of reductive characters in wine.

© Reprinted with permission from Ugliano, M., Fedrizzi, B., Siebert, T., Travis, B., Magno, F., Versini, G., Henschke, P.A. Effect of nitrogen supplementation and Saccharomyces species on hydrogen sulfide and other volatile sulfur compounds in Shiraz fermentation and wine. J. Agric. Food Chem. DOI:10.1021/jf8037693, 1–8; 2009. Copyright 2009 American Chemical Society.

1122 Ugliano, M., Henschke, P.A. Yeast and wine flavour. Moreno-Arribas, V., Polo, M.C. (Eds.). In Wine Chemistry and Biochemistry. New York: Springer, Chapter 8D, pp. 313–392; 2009.

This chapter summarises the microbiological, physiological and biochemical interactions between grape compounds and yeast metabolism that lead to the development of wine flavour. The role of different yeasts and inoculation strategies in the modulation of wine flavour are highlighted, and the potential for improving wine flavour by advanced screening and genetic techniques is briefly discussed.

© Reprinted with permission from Ugliano, M., Henschke, P.A. Yeast and wine flavour. Moreno-Arribas, V., Polo, M.C. (Eds.). In Wine Chemistry and Biochemistry. New York: Springer, Chapter 8D, pp. 313–392; 2009. Copyright 2009 Springer Science+Business Media, LLC.

1123 Varela, C., Siebert, T., Cozzolino, D., Rose, L., McLean, H., Henschke, P.A. Discovering a chemical basis for differentiating wines made by fermentation with ‘wild’ indigenous and inoculated yeasts: role of yeast volatile compounds. Aust. J. Grape Wine Res. DOI: 10.1111/j.1755-0238.2009.00054.x, 1–11; 2009.

Background and Aims: Winemakers are constantly searching for new techniques to modulate wine style. Exploiting indigenous yeasts present in grape must is re-emerging as a commercial option in New World wine regions. Wines made with indigenous or ‘wild’ yeasts are perceived to be more complex by showing a greater diversity of flavours; however, the chemical basis for the flavour characteristics is not yet defined. In order to evaluate techniques for making wine with the ‘wild yeast fermentation’ character more reliably, it is necessary to define the salient chemical characteristics of such wines. Methods and Results: Pairs of Chardonnay wines were prepared from the same must and subjected to similar fermentation conditions in the wineries of origin, except for the mode of inoculation. Reference wines were made by inoculation with a Saccharomyces cerevisiae starter culture, whereas companion wines were allowed to undergo fermentation with the indigenous microflora. Of all wine chemicals

60 Technical Review No. 180 June 2009 analysed, only yeast-derived volatile fermentation products showed significant differences between the yeast treatments. Conclusions: Inoculated wines were associated with the esters ethyl hexanoate and 3-methylbutyl acetate and formed a clear cluster by principal component analysis. By comparison with inoculated wines, ‘wild’ yeast fermented wines showed high variability in volatile compounds that contribute to wine aroma, with higher concentrations of 2-methylpropanol, 2-methylbutanoic acid, ethyl 2-methylpropanoate, ethyl decanoate and ethyl dodecanoate potentially being sensorially important. Significance of the Study: This study shows that yeast-derived volatile fermentation products are a key difference between inoculated and uninoculated ferments and provides a chemical basis for the ‘wild yeast fermentation’ character.

© Reprinted with permission from Varela, C., Siebert, T., Cozzolino, D., Rose, L., McLean, H., Henschke, P.A. Discovering a chemical basis for differentiating wines made by fermentation with ‘wild’ indigenous and inoculated yeasts: role of yeast volatile compounds. Aust. J. Grape Wine Res. DOI: 10.1111/j.1755-0238.2009.00054.x, 1–11; 2009. Copyright 2009 Australian Society of Viticulture and Oenology.

1124 Cooke, R.C., Capone, D.L., van Leeuwen, K.A., Elsey, G.M., Sefton, M.A. Quantification of several 4-alkyl substituted γ-lactones in Australian wines. J. Agric. Food Chem. 57(2), 348–352; 2009.

Stable isotope dilution assays have been developed for γ-octalactone (1), γ-nonalactone (2), γ-decalactone 2 (3) and γ-dodecalactone (4) in both white and red wines for the first time. H7-analogues of each lactone were prepared for use as internal standards via a strategy employing ring-opening, esterification and oxidation of the respective starting lactones. The methods were shown to be highly accurate and reproducible (R2 ≥ 0.999; SD ≤ 1%). A large selection of Australian wines (n = 178) were analyzed for the presence of lactones 1−4. Fifty-eight white wines covering the varieties Chardonnay, Riesling, Sauvignon Blanc, Semillon and Viognier, as well as Botrytis style wines, were analyzed and showed broadly that γ-octalactone (1) was the most common lactone, being observed above its limit of detection in 28 of the wines, followed by γ-nonalactone (2) in 23 wines. The Botrytis style white wines had the highest concentrations of 1 and 2 (maximum concentrations 8.5 and 59 μg/L respectively). A total of 120 red wines covering the varieties Cabernet Sauvignon, Durif, Merlot, Pinot Noir and Shiraz were also studied and showed γ-octalactone (1) and γ-nonalactone (2) to be the most common lactones present, in 56 and 57 of the wines, respectively. γ-Decalactone (3) was observed in only a small number (13) of red wine samples and not at all in the white varieties. γ-Dodecalactone (4) was absent from all 178 samples studied. The highest concentrations of lactones 1, 2 and 3 in the red wines were 4.2, 39.7 and 4.0 μg/L respectively.

© Reprinted with permission from Cooke, R.C., Capone, D.L., van Leeuwen, K.A., Elsey, G.M., Sefton, M.A. Quantification of several 4-alkyl substituted γ-lactones in Australian wines. J. Agric. Food Chem. 57(2), 348–352; 2009. Copyright 2009 American Chemical Society.

June 2009 Technical Review No. 180 61 L 1125 Cowey, G., Coulter, A., Holdstock, M. Brines, paints, oils and the occasional mobile phone – common vintage contaminants. Aust. N.Z. Grapegrower Winemaker 541, 60–65; 2009.

The start of vintage is the highest risk time for grape, juice and wine contamination. Potential contaminations include refrigerant brine from cooling systems, hydraulic oil from vineyard and winery machinery and taints from painted grape bins. Preventative steps should be taken during the pre-vintage period to avoid costly contaminations occurring in your winery.

© Reprinted with permission from Cowey, G., Coulter, A., Holdstock, M. Brines, paints, oils and the occasional mobile phone – common vintage contaminants. Aust. N.Z. Grapegrower Winemaker 541, 60–65; 2009. Copyright 2009 Winetitles Pty Ltd.

1126 Cozzolino, D., Holdstock, M., Dambergs, R.G., Cynkar, W.U., Smith, P.A. Unleashing the secrets of organic wine grown in Australia using infrared light. Aust. N.Z. Wine Ind. J. 24(1), 15–17; 2009.

The use of mid infra-red (MIR) spectroscopy has been implemented in many wineries for routine analysis of wine compositional parameters. The ability to provide detailed chemical information and simultaneously measure several analytes has been the impetus for developing spectroscopic methods. Compared with traditional laboratory methods, spectroscopic techniques often give new and better insight into complex problems by measuring a great number of chemical compounds at once, therefore enabling the ‘fingerprinting’ of each sample. This research has shown that the classification techniques applied were able to extract useful information from the MIR spectra to differentiate wines produced under organic and non-organic systems.

© Reprinted with permission from Cozzolino, D., Holdstock, M., Dambergs, R.G., Cynkar, W.U., Smith, P.A. Unleashing the secrets of organic wine grown in Australia using infrared light. Aust. N.Z. Wine Ind. J. 24(1), 15–17; 2009. Copyright 2009 Winetitles Pty Ltd.

1127 Daniel, M.A., Capone, D.L., Sefton, M.A., Elsey, G.M. Riesling acetal is a precursor to 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) in wine. Aust. J. Grape Wine Res. 15(1), 93–96; 2009.

Background and Aims: Knowledge of the formation and fate of aroma compounds is important to an understanding of the processes that affect wine composition and flavour. This study aimed to investigate the competitive formation and degradation of 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) and 2,2,6,8-tetramethyl-7,11-dioxatricyclo[6.2.1.01,6]undec-4-ene (Riesling acetal) under wine storage conditions. Methods and Results: 1,1,5-trimethyl-3,6-dihydroxy-9,9-ethylenedioxymegastigm-4-ene was synthesised in the laboratory by using standard organic chemistry transformation methodology and was subsequently used to prepare both Riesling acetal and TDN. At 45°C in model wine, approximately 40% of Riesling acetal was converted to TDN after 60 days at pH 3.2, whereas 80% was converted after

62 Technical Review No. 180 June 2009 60 days at pH 3.0, as established by GC/MS analysis. Under more vigorous conditions, this conversion was complete and the TDN thus formed was completely stable. Conclusion: Riesling acetal is a precursor to TDN at wine pH, rather than a competing end-product formed by the acid-catalysed hydrolysis of precursors common to both compounds. TDN is chemically stable to wine acid. Significance of the Study: The findings provide a clearer understanding of the factors affecting the concentration of TDN (kerosene, bottle-age aroma) in older wines and thereby have the potential to indicate strategies for modulating the formation of TDN.

© Reprinted with permission from Daniel, M.A., Capone, D.L., Sefton, M.A., Elsey, G.M. Riesling acetal is a precursor to 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) in wine. Aust. J. Grape Wine Res. 15(1), 93–96; 2009. Copyright 2009 Australian Society of Viticulture and Oenology.

1128 Collins, C., Dry, P. Managing fruitset in vineyards. Aust. Vitic. 13(1), 53–54; 2009.

Poor fruitset can limit the yield of many varieties especially in cool-climate regions. Researchers at The University of Adelaide have revisited the application of cultural practices and plant growth regulators as management options to manipulate fruitset.

1129 Oberholster, A., Francis, I.L., Iland, P.G., Waters, E.J. Mouthfeel of white wines made with and without pomace contact and added anthocyanins. Aust. J. Grape Wine Res. 15(1), 59–69; 2009.

Background and Aims: The contribution of anthocyanins or tannin–anthocyanin reaction products to the mouthfeel properties of wines prepared from both red and white fruit with and without pomace contact and anthocyanin addition was investigated. Methods and Results: A trained sensory panel rated mouthfeel and taste attributes in wines after 6 months of bottle storage and phenolic measures were obtained. A white wine made in the same manner to how a red wine is made did not exhibit the same mouthfeel sensory attributes of a red wine: it was lower in viscosity, less particulate in nature and lower in intensity for the astringency descriptors fine emery, dry and grippy.Conclusions: It was found that differences in ratings of mouthfeel attributes could not be related closely to phenolic composition or structure. This study has shown that the presence of anthocyanins during fermentation increases the intensity of astringency attributes. Significance of the Study: Using the mouthfeel wheel, the differences between a white wine made like a red wine and a red wine could be quantified. It was also shown that the presence of anthocyanins in red wine can explain the differences perceived between the mouthfeel properties of a white and a red wine.

© Reprinted with permission from Oberholster, A., Francis, I.L., Iland, P.G., Waters, E.J. Mouthfeel of white wines made with and without pomace contact and added anthocyanins. Aust. J. Grape Wine Res. 15(1), 59–69; 2009. Copyright 2009 Australian Society of Viticulture and Oenology. C

June 2009 Technical Review No. 180 63 L 1130 O’Brien, V., Colby, C., Nygaard, M. Managing oxygen ingress at bottling. Aust. N.Z. Wine Ind. J. 24(1), 24–29; 2009.

AWRI Commerical Service and Nomacorc recently collaborated to study the management of oxygen ingress in bottles, using Nomacorc’s proprietary PreSens technology for oxygen measurement in wine bottles. This article details the study’s outcomes.

1131 Osidacz, P., Francis, L. What the Chinese want. WBM February, 58–61; 2009.

In a large consumer sensory study involving more than 300 consumers in China, Australian wines were the best liked on a blind basis and a Chinese Merlot was the least liked. Three segments were identified with distinct sensory preferences. 50% of the consumers preferred sweeter wines with less strong aromas and flavours, while 20% preferred more strongly flavoured wines and were more likely to be newer wine consumers. The final group reacted negatively to wines with earthy, barnyard or bruised fruit flavours. This investigation also provided valuable information on Chinese purchase behaviour and attitudes to wine. These results will help the Australian wine sector to target the Chinese growing market.

1132 Stockley, C.S., Simos, C.A., Pretorius, I.S. To your health. Aust. N.Z. Wine Ind. J. 24(1), 18–20; 2009.

Moderate wine drinking has been shown to have health benefits for men and women in later life, who are at greater risk of heart trouble and cardiovascular disease. The ‘French Paradox’ was a turning point in showing how moderate wine drinking, with meals, could help people live longer. Since 1992, scientists have tried to understand how the paradox works by investigating phenolic compounds and their effect on human health. Results so far have shown that phenolics do help to protect the heart and blood vessels from damage. The AWRI is part of collaborations taking the research further to look at how phenolics work when they are metabolised, or used in the body. The AWRI is also monitoring new investigations and discoveries connecting moderate wine drinking to cancer prevention and better cognitive function.

64 Technical Review No. 180 June 2009 1133 Sun, H., Ma, H., Hao, M., Pretorius, I.S., Chen, S. Identification of yeast population dynamics of spontaneous fermentation in Beijing wine region, China. Ann. Microbiol. 59(1), 69–76; 2009.

The aim of this study was (i) to investigate changes occurring in the yeast population profile during spontaneous fermentation of grape juice; (ii) to assess the proliferation of commercial yeast starter culture strains in vineyards; and (iii) to identify indigenous wine strains for future development of starter strains that better reflect the yeast biodiversity of China’s grape-growing regions. To achieve this, yeasts were isolated at four different stages during fermentation of both hand-pressed and winery-sourced must samples of Vitis vinifera L. cv. Roussanne and Merlot. A total of 1600 yeast colonies were isolated and then grouped according to macroscopic and microscopic characteristics. A selection of 291 colonies from the different groups was subjected to species identification using the internal transcribed spacer regions of the 5.8S rRNA gene (ITS1-5.8S-ITS2 region) and the inter-delta (δ) sequence of the 26S rRNA D1/D2 region. In addition, 104 Saccharomyces cerevisiae colonies were subjected to strain identification. Twelve species belonging to nine different genera were found amongst the isolates. During the early stages of fermentation, it was found that Hanseniaspora uvarum and Candida stellata numerically dominated the four to six yeast species present, including a region-specific yeast, Sporobolomyces beijingensis. Two S. cerevisiae strains were isolated from the final stage of fermentation. These two indigenous strains, which were found to be different from the nine commercial yeast strains previously used as starter cultures in this particular Beijing-based winery, might possess potentially important region-specific oenological characteristics. This study provides the first essential step towards the preservation and exploitation of the hidden oenological potential of the untapped wealth of yeast biodiversity in China’s wine-producing regions.

© Reprinted with permission from Sun, H., Ma, H., Hao, M., Pretorius, I.S., Chen, S. Identification of yeast population dynamics of spontaneous fermentation in Beijing wine region, China. Ann. Microbiol. 59(1), 69–76; 2009. Copyright 2009 University of Milan. w

June 2009 Technical Review No. 180 65 L AWRI extension and roadshow calendar

June 2009 AWRI Roadshow: • Fleurieu Zone – McLaren Vale SA • Mt Lofty Ranges Zone – Langhorne Creek SA Technical Review 180 June 2009 July 2009 Advanced Wine Assessment Course (21–24 July) – Adelaide AWRI Roadshows: • Granite Belt Zone – Stanthorpe QLD August 2009 AWRI Roadshow: • Orange & Cowra NSW Technical Review 181 August 2009 October 2009 AWRI Roadshows: • Port Phillip Zone – Geelong Vic • Limestone Coast Zone – Coonawarra SA Technical Review 182 October 2009 November 2009 AWRI Roadshows: • Mount Lofty Ranges Zone and Far North Zone – Clare Valley SA • Barossa Zone – Barossa Valley SA December 2009 Technical Review 183 December 2009 January 2010 AWRI Roadshows: • Northern Slopes Zone – New England NSW February 2010 Technical Review 184 February 2010

For further information, please contact Virgina Phillips on (08) 8303 6687 or [email protected].

* Details subject to change without notice. Please visit the AWRI website to view the most up to date copy of this calendar at www.awri.com.au/industry_development/events/. All information was accurate at time of compilation.

66 Technical Review No. 180 June 2009 Conference calendar

24–25 June 2009 Winery Engineering Association National Conference and Exhibition, Morphetville, Adelaide, SA. W: www.wea.org.au

28 June – 3 July 2009 XXXII World Congress of Vine and Wine and General Assembly of the International Organisation of Vine and Wine (OIV), Zagreb, Croatia. W: www.oiv.int

2–4 July 2009 In Vino Analytica Scientia Symposium, Angers, France. W: invinoanalyticascientia.groupe-esa. com

17–19 July 2009 Pinot Noir Forum – Tasmania 2009, Swansea, TAS. W: www.pinot-noir.org

April 2010 9th International Symposium on Innovations in Enology, Stuttgart, Germany. W: www.intervitis- interfructa.de/kongress. International Symposium on Technology in Viticulture, Stuttgart, Germany. W: www.intervitis- interfructa.de. 3rd International Symposium on Organic Wine Growing: Guidelines for Organic Enology, Stuttgart, Germany. W: www.intervitis-interfructa.de.

21–22 June 2010 International Cool Climate Symposium for Viticulture and Oenology, Seattle, Washington, USA. W: asev.org

3–8 July 2010 14th Australian Wine Industry Technical Conference, Adelaide Convention Centre, Adelaide, SA. Info: Kate Beames—Conference Manager, T: +61 8 8303 6821; F: +61 8 8303 6686; E: info@ awitc.com.au; W: www.awitc.com.au

June 2009 Technical Review No. 180 67 The Technical Review is published bimonthly by The Australian Wine Research Institute. It is available free of charge to Australian grape and wine sector members paying a levy under the Wine Grapes Levy Act, however, other interested organisations and individuals may subscribe to Technical Review.

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68 Technical Review No. 180 June 2009