DOCSLIB.ORG

Malolactic Fermentation in Wine

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Malolactic Fermentation in Wine DUBROVNIK DUBROVNIK PART 1: SENSORY DEVELOPMENT OF HOT-CLIMATE RED VARIETALS DURING FERMENTATION DURING RED VARIETALS OF HOT-CLIMATE DEVELOPMENT 1: SENSORY PART APRIL 28, 2011 AND THE CURRENT MARKET SITUATION MANAGEMENT WINE FERMENTATION 2: ROSÉ PART APRIL 28, 2011 PART 1 E SENSORY DEVELOPMENT OF HOT-CLIMATE RED VARIETALS DURING FERMENTATION PART 2 TION IN WIN A ROSÉ WINE FERMENTATION MANAGEMENT T 18 AND THE CURRENT MARKET SITUATION 18 CTIC FERMEN A L O L MA DUBROVNIK, APRIL 28, 2011 PART 1 SENSORY DEVELOPMENT OF HOT-CLIMATE RED VARIETALS DURING FERMENTATION PART 2 ROSÉ WINE FERMENTATION MANAGEMENT AND THE CURRENT MARKET SITUATION PROCEEDINGS OF THE XXIIes ENTRETIENS SCIENTIFIQUES LALLEMAND FOREWORD his year, the XXIIes Entretiens Scientifiques Lal- results show that significant sensory and compositional lemand were a two-part event focused first on differences occur as a result of different malolactic fer- T hot-climate red varietals and understanding their mentation treatments, including differences in the inten- sensory development, and, second, on rosé winemaking sity of perceived fruit flavour. The first part of the meeting and the impact of different techniques on the wine style, concluded with a presentation by Dr. Charles Edwards including a presentation on the rosé wine market. from Washington State University, United States. The im- pact of molecular sulphur dioxide (mSO ) and filtration The meeting gathered some of the top scientists in the 2 requirements to control Brettanomyces bruxellensis yeast field to present these topics to an international crowd, in- was also presented. cluding winemakers from Eastern Europe, and was an op- portunity to hand out the Lallemand awards. The student The second part of the Entretiens Scientifiques Lallemand award, the Prix Michel-Feuillat – Entretiens Scientifiques focused on rosé wines. Dr. Antonio Palacios presented the Lallemand, was awarded to Dr. Guillaume Antalick from results of a joint study by Lallemand, Litmus Wines (Unit- the Université de Bordeaux II for his work on “Biochemi- ed Kingdom), three wineries (in Spain, France and Portu- cal and sensory changes associated with fruity notes in gal) and a large U.K. retailer. The study looked at making red wines during malolactic fermentation. The impor- rosé wines with selected yeasts and a specific protocol. tance of esters.” The Lallemand – Institute of Masters of One key element for rosé wine is fermentation manage- Wine bursary was awarded to Sharon Wild, a second-year ment established with a proper nutrition strategy to avoid Master of Wine student from Australia for her essay re- struck fermentation and related defects. Baptiste Olivier sponding to “Discuss the evolution of rosé wine styles and from the ICV, France, presented Good Nutritional Prac- consumer preferences globally over the past five years.” tices that aim to satisfy the needs of the yeast in order to Also on hand were the winners of the ML Wines competi- obtain a viable population large enough to complete al- tion (Madrid 2011), who received their prizes from the coholic fermentation. The Centre du Rosé in the Provence president of Lallemand, Mr. Jean Chagnon. region of France was represented by Dr. Laure Cayla, who The meeting opened with a presentation by Professor Rémi discussed the numerous tools that have been developed to Guérin-Schneider from IFV Rhône Méditerranée in Mont- describe the rosé colour palette and to adapt the selected pellier, France, about the impact of yeast on the aromatic winemaking process according to the desired colour ob- potential of grapes during fermentation. His presentation jective. The management of colour is based on the choice showed that yeast fermentation is a key component in the of varietal and the good management of pre-fermentation biotransformation of varietal precursors and is responsible operations. The winemaker can direct the sensory profile for much more than the production of secondary metabo- of rosé wines through the choice of techniques, input and lites from amino acids and sugars. equipment, so the sensory quality of the wines meets the needs of different markets. The last presentation of the Professor Fernando Zamora from Universitat Rovira i Vir- day was a departure from the scientific ones, as Lucy Cle- gili in Tarragona, Spain, addressed the impact of climate ments, from Sainsbury Supermarkets, U.K., presented on change on grape ripening and the challenge it presents the rosé market in the U.K. and the company’s approach to the wine industry. Different scenarios were discussed to consumer preferences. on how to minimize the impact on the wine, such as us- ing lees or inactive yeast to enrich the wine with polysac- In both red and rosé wines, the sensory impacts of yeast charides to increase mouthfeel and reduce bitterness, as- and bacteria are now better understood, and ongoing tringency and herbaceous characters, as well as applying research lets us understand the mechanisms behind the techniques for the partial dealcoholization of wines. processes, so winemakers and, ultimately, wine drinkers can benefit from this information. The primary goal of our Dr. Eveline Bartowsky from the AWRI, Australia, present- investment in research is to translate scientific results into ed the progress on her work on the influence of malolac- improvements in wine quality. tic fermentation on the fruity character of red wines. Her – 3 – CONTENTS PART 1: SENSORY DEVELOPMENT OF HOT-CLIMATE PART 2: ROSÉ WINE FERMENTATION MANAGEMENT RED VARIETALS DURING FERMENTATION AND THE CURRENT MARKET SITUATION ImpaCT OF YEAST ON THE AROmatIC POTENTIAL BIOLOGICAL MANAGEMENT IN ROSÉ WINE OF GRAPES DURING FERMENtatION .....................7 PRODUCTION TO PRESERVE VARIEtal AND Rémi GUÉRIN-SCHNEIDER and Laurent DAGAN FRUITY CHARACTERISTICS FOR THE INTERNatIONAL MARKET ......................................37 Ann DUMONT, José Maria HERAS, ADAPTING WINEMAKING TO WARM-CLImatE Anthony SILVANO, Sam HARROP CONDITIONS ..........................................................17 and Antonio PALACIOS Fernando ZAMORA YEAST NUTRITION AND THE ALCOHOLIC INFLUENCE OF MALOLACTIC FERMENtatION FERMENtatION OF ROSÉ WINES ...........................49 ON THE FRUITY CHARACTERS OF RED WINE: Baptiste OLIVIER and Daniel GRANÈS BRINGING CHEMISTRY AND SENSORY SCIENCE TOGETHER ..............................................................25 Eveline BARTOWSKY, Peter COSTELLO, INNOvatIVE PROCESSES, EQUIPMENT AND Sibylle KRIEGER-WEBER, Andrew MARKIDES, INPUT TO DESIGN ROSÉ WINES FOR DIFFERENT Leigh FRANCIS and Brooke TRAVIS MARKETS .................................................................55 Laure CAYLA and Gilles MASSON CONTROLLING BRETTANOMYCES .........................33 Charles G. EDWARDS BIOCHEMICAL AND SENSORIAL IMPACT ON THE FRUITY NOTE IN RED WINES DURING MALOLACTIC FERMENTATION: THE SPECIAL ROLE OF ESTERS ......................................................60 Guillaume ANTALICK Winner of the Prix Michel-Feuillat – Entretiens Scientifiques Lallemand 2011 – Summary of Doctoral Thesis THE EVOLUTION OF ROSÉ WINE STYLES AND CONSUMER PREFERENCES GLOBALLY OVER THE PAST FIVE YEARS .....................................................61 Sharon WILD – Second-year Master of Wine – Australia, Winner of the Lallemand – Institute of Masters of Wine Bursary – Essay – 5 – PART 1: SENSORY DEVELOPMENT OF HOT-CLIMATE RED VARIETALS DURING FERMENTATION ImpaCT OF YEAST ON THE AROmatIC POTENTIAL OF GRAPES DURING FERMENtatION Rémi GUÉRIN-SCHNEIDER1, 2 and Laurent Dagan2 1 UMT Qualinnov, INRA-IFV, 2 place Pierre Viala, 34060 Montpellier, France 2 Analyse et Conseil, bâtiment 28, 2 place Pierre Viala, 34060 Montpellier, France [email protected] Abstract from a non-volatile precursor (PDMS) by a pure chemi- cal reaction. That precursor was recently identified as S- Alcoholic fermentation is one of the key steps in the pro- methylmethionine. The role of yeast in this mechanism is cess of winemaking. In addition to the major bioreactions not yet clear, although no relation was observed between resulting from yeast activity, such as alcohol production, the PDMS levels in must and those found in wines af- secondary metabolites are produced and some are in- ter fermentation. A recent study supported by Lallemand volved in developing the sensory characteristics of wines. showed that yeast is able to metabolize S-methylmethio- As the major secondary volatile metabolites produced nine, likely as a sulphur/nitrogen source, and thus lower by yeast are generated by non-specific substrates (amino the precursor level in wines. The strain of yeast and nitro- acids, sugars, etc.), until recently yeast was considered gen nutrition appear to be two elements involved in the unable to interact with qualitative varietal compounds. modulation of this degradation, and, therefore, in the pilot However, in the past 10 years, research has demonstrated wine typology. that yeast fermentation is also a key component in the biotransformation of varietal precursors. 1. Introduction Two examples of biotransformation will be developed. The aroma potential of grapes includes several classes The first deals with varietal thiols generated from specific of specific non-volatile compounds, the so-called aro- precursors (cysteine or glutathione conjugates) by C-S ma precursors, which have in common being present in lyase activity of yeast during fermentation. These aroma grapes at the harvest, and are transformed into volatile compounds are key in several white and rosé wines, and compounds
Load more

Recommended publications
  • Ing to Unpublished Data of Douglas and Vaughn.) Arena (1936)
    THE pH REQUIREMENTS OF SOME HETEROFERMEN- TATIVE SPECIES OF LACTOBACILLUS JOHN C. M. FORNACHON,1 HOWARD C. DOUGLAS AND REESE H. VAUGHN Division of Fruit Products, University of California, Berkeley, California Received for publication May 6, 1940 I. INTRODUCTION The lactobacilli are noted for their ability to grow in acid media. Although media with reactions between pH 3.5 and 5.0 have been recommended for their isolation, the media used in physiological studies by Pederson (1929, 1938), Nelson and Werkman (1935, 1936), Weinstein and Rettger (1932) and others had values ranging from pH 6.2 to 7.0. Shimwell (1935) found the optimum pH for the growth of LactobaciUus pastorianus to be approximately 8.0. It has been observed however that species of Lactobacillus isolated from wines and other similar products thrive best when the medium is appreciably acid. Otani (1936) pointed out that homofermen- tative lactobacilli isolated from sake grew most vigorously be- tween pH 4.0 and 5.0 Fornachon (1936) found the optimum pH for the growth of a heterofermentative species of Lactobacillus isolated from Australian wine to be between pH 4.0 and 5.0. Douglas and McClung (1937) reported a bacterium from Califor- nia wine with an optimum pH between 4.1 and 4.3. (This organism is a heterofermentative species of LactobaciUus accord- ing to unpublished data of Douglas and Vaughn.) Arena (1936) described several lactic acid bacteria isolated from Argentinian wine and found the optimum pH for growth to vary between pH 4.3 and 6.7. 1 Research Officer, Australian Wine Board, Waite Agricultural Research In- stitute, University of Adelaide, South Australia.
    [Show full text]
  • Malolactic Fermentation in Red Wine
    Fact Sheet WINEMAKING Malolactic fermentation in red wine Introduction Malolactic fermentation (MLF) is a secondary bacterial fermentation carried out in most red wines. Oenococcus oeni, a member of the lactic acid bacteria (LAB) family, is the main bacterium responsible for conducting MLF, due to its ability to survive the harsh conditions of wine (high alcohol, low pH and low nutrients) and its production of desirable wine sensory attributes. One of the important roles of MLF is to confer microbiological stability towards further metabolism of L-malic acid. Specifically, MLF removes the L-malic acid in wine that can be a carbon source for yeast and bacterial growth, potentially leading to spoilage, spritz and unwanted flavours. MLF can also be conducted in some wines to influence wine style. MLF often occurs naturally after the completion of primary fermentation or can also be induced by inoculation with a selected bacterial strain. Since natural or ‘wild’ MLF can be unpredictable in both time of onset and impact on wine quality, malolactic starter cultures are commonly used. In Australia, almost all red wines undergo MLF and 74% are inoculated with bacterial starter cultures (Nordestgaard 2019). This fact sheet provides practical information for induction of MLF in red wine. A separate fact sheet provides equivalent information for white and sparkling base wine. These should also be read in conjunction with another fact sheet, Achieving successful malolactic fermentation, which gives further practical guidelines for MLF induction, monitoring and management. Updated September 2020 Fact Sheet WINEMAKING Key parameters for a successful MLF in red wine Composition of red wine/must The main wine compositional factors that determine the success of MLF are alcohol, pH, temperature and sulfur dioxide (SO2) concentration.
    [Show full text]
  • A Taxonomic Note on the Genus Lactobacillus
    Taxonomic Description template 1 A taxonomic note on the genus Lactobacillus: 2 Description of 23 novel genera, emended description 3 of the genus Lactobacillus Beijerinck 1901, and union 4 of Lactobacillaceae and Leuconostocaceae 5 Jinshui Zheng1, $, Stijn Wittouck2, $, Elisa Salvetti3, $, Charles M.A.P. Franz4, Hugh M.B. Harris5, Paola 6 Mattarelli6, Paul W. O’Toole5, Bruno Pot7, Peter Vandamme8, Jens Walter9, 10, Koichi Watanabe11, 12, 7 Sander Wuyts2, Giovanna E. Felis3, #*, Michael G. Gänzle9, 13#*, Sarah Lebeer2 # 8 '© [Jinshui Zheng, Stijn Wittouck, Elisa Salvetti, Charles M.A.P. Franz, Hugh M.B. Harris, Paola 9 Mattarelli, Paul W. O’Toole, Bruno Pot, Peter Vandamme, Jens Walter, Koichi Watanabe, Sander 10 Wuyts, Giovanna E. Felis, Michael G. Gänzle, Sarah Lebeer]. 11 The definitive peer reviewed, edited version of this article is published in International Journal of 12 Systematic and Evolutionary Microbiology, https://doi.org/10.1099/ijsem.0.004107 13 1Huazhong Agricultural University, State Key Laboratory of Agricultural Microbiology, Hubei Key 14 Laboratory of Agricultural Bioinformatics, Wuhan, Hubei, P.R. China. 15 2Research Group Environmental Ecology and Applied Microbiology, Department of Bioscience 16 Engineering, University of Antwerp, Antwerp, Belgium 17 3 Dept. of Biotechnology, University of Verona, Verona, Italy 18 4 Max Rubner‐Institut, Department of Microbiology and Biotechnology, Kiel, Germany 19 5 School of Microbiology & APC Microbiome Ireland, University College Cork, Co. Cork, Ireland 20 6 University of Bologna, Dept. of Agricultural and Food Sciences, Bologna, Italy 21 7 Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Vrije Universiteit 22 Brussel, Brussels, Belgium 23 8 Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, 24 Belgium 25 9 Department of Agricultural, Food & Nutritional Science, University of Alberta, Edmonton, Canada 26 10 Department of Biological Sciences, University of Alberta, Edmonton, Canada 27 11 National Taiwan University, Dept.
    [Show full text]
  • The U.S. Wine Industry and Selected Trade Issues with the European Union
    The U.S. Wine Industry and Selected Trade Issues with the European Union Renée Johnson Specialist in Agricultural Policy July 25, 2016 Congressional Research Service 7-5700 www.crs.gov R43658 The U.S. Wine Industry and Selected Trade Issues with the European Union Overview This report provides an overview of issues pertaining to the U.S. wine industry within ongoing U.S. trade negotiations in the proposed Trans-Pacific Partnership (TPP) and the proposed Transatlantic Trade and Investment Partnership (T-TIP). The report is organized in two parts. The first part provides an overview of global wine production and trade, focusing on the role of the United States within the industry. The second part provides an overview of reported barriers to trade for U.S. wine exporters, and describes some of the issues that are reportedly being discussed as part of the ongoing TPP and T-TIP negotiations that could influence market access, regulations, and rules related to wine trade. Given the magnitude of wine trade between the United States and the European Union (EU), much of the discussion in this report focuses on U.S. wine trade issues related to the EU. A few introductory comments are worth noting. There is some disagreement among countries over what constitutes “wine.” For example, the EU defines wine as only those beverages made by fermenting grapes. In the United States, wine is defined more broadly to include beverages produced by fermentation of any fruit (grapes, peaches, pears, etc.). European table wine generally contains between 9% and 15% alcohol. In contrast, U.S.
    [Show full text]
  • Conducting a Successful Malolactic Fermentation
    CONDUCTING A SUCCESSFUL MALOLACTIC FERMENTATION PARAMETERPA RECOMMENDATION ACTION Grapes pH Between 3.20 and 3.50 Acid addition after cold soak FruitFru condition Visible rot, off odors Sorting Crush/Destem SO2SO < 40 mg/L total for white Minimize SO2 by using sound grapes Maceration < 70 mg/L total for red PotentialPPot alcohol < 13.5 % Harvest parameters Alcoholic YeastYeY a strain Use yeast strain that is compatible with ML bacteria Check with yeast supplier Fermentation InoculationIno strategy Inoculate with starter culture Direct, Step 1, or Build up: follow manufacturer Timing Post-alcoholic fermentation recommendation Strain Consider strains recommended for certain Strains available with low pH tolerance, high SO2 tolerance difficult wine conditions and high alcohol tolerance Malolactic TemperatureTem 64-71°F (18-22°C) Inoculate while wine still warm from primary ferment Fermentation Temp-controlled cellar/tanks SO2SO < 5 mg/L free NO SO2 additions until MLF complete AlcoholAlc < 13.5% Consider higher alcohol tolerant ML strain Use acclimatization steps for culture prior to inoculation pH 3.20 to 3.50 Acid adjustment if necessary (not recommended during MLF) Be alert to microbial spoilage issues if you have a high pH NNutrientsu Consider ML nutrients if vineyard lots have been Follow manufacturer recommendation problematic in the past or you used high nutrient demand yeast strain Conduct MLF on yeast lees Keep wine on light lees during MLF MMLFL progress Regular monitoring Paper chromatography, enzymatic analysis, external lab analysis Microscopic examination for Lactobacillus, If presence of spoilage bacteria consider lysozyme and Pediococcus re-inoculation after 2-3 weeks Monitor VA as indicator of spoilage bacteria PCR analysis Post Fermentation MLFML completion Malic acid < 30-50 mg/L Confirm with enzymatic assay or external lab analysis before & Aging making SO2 addition.
    [Show full text]
  • The Many Faces of Kefir Fermented Dairy Products
    nutrients Review The Many Faces of Kefir Fermented Dairy Products: Quality Characteristics, Flavour Chemistry, Nutritional Value, Health Benefits, and Safety Mohamed A. Farag 1,2,*, Suzan A. Jomaa 2, Aida Abd El-Wahed 3,4 and Hesham R. El-Seedi 4,5,6,7,* 1 Pharmacognosy Department, College of Pharmacy, Cairo University, Kasr El Aini St., P.B., Cairo 11562, Egypt 2 Chemistry Department, School of Sciences & Engineering, The American University in Cairo, New Cairo 11835, Egypt; [email protected] 3 Department of Bee Research, Plant Protection Research Institute, Agricultural Research Centre, Giza 12627, Egypt; [email protected] 4 Pharmacognosy Group, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, Box 574, SE-751 23 Uppsala, Sweden 5 Al-Rayan Research and Innovation Center, Al-Rayan Colleges, Medina 42541, Saudi Arabia 6 International Research Center for Food Nutrition and Safety, Jiangsu University, Zhenjiang 212013, China 7 Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE 106 91 Stockholm, Sweden * Correspondence: [email protected] or [email protected] (M.A.F.); [email protected] (H.R.E.-S.); Tel.: +20-011-202-2362245 (M.A.F.); +46-18-4714496 (H.R.E.-S.) Received: 22 November 2019; Accepted: 18 January 2020; Published: 28 January 2020 Abstract: Kefir is a dairy product that can be prepared from different milk types, such as goat, buffalo, sheep, camel, or cow via microbial fermentation (inoculating milk with kefir grains). As such, kefir contains various bacteria and yeasts which influence its chemical and sensory characteristics. A mixture of two kinds of milk promotes kefir sensory and rheological properties aside from improving its nutritional value.
    [Show full text]
  • Effect of Phenolic Aldehydes and Flavonoids on Growth And
    ARTICLE IN PRESS Effect of phenolic aldehydes and flavonoids on growth and inactivation of Oenococcus oeni and Lactobacillus hilgardii Ana Rita Figueiredoa, Francisco Camposa,Vı´ctor de Freitasb, Tim Hogga, Jose´Anto´nio Coutoa,Ã aEscola Superior de Biotecnologia, Universidade Cato´lica Portuguesa, Rua Dr. Anto´nio Bernardino de Almeida, 4200-072 Porto, Portugal bFaculdade de Cieˆncias do Porto, Departamento de Quı´mica, Centro de Investigac-a˜o em Quı´mica, Rua do Campo Alegre 687, 4169-007 Porto, Portugal Keywords: Lactic acid bacteria; Phenolic aldehydes; Flavonoids; Tannins; Wine The aim of this work was to investigate the effect of wine phenolic aldehydes, flavonoids and tannins on growth and viability of strains of Oenococcus oeni and Lactobacillus hilgardii. Cultures were grown in ethanol-containing MRS/TJ medium supplemented with different concentrations of phenolic aldehydes or flavonoids and monitored spectrophotometrically. The effect of tannins was evaluated by monitoring the progressive inactivation of cells in ethanol-containing phosphate buffer supplemented with grape seed extracts with different molecular weight tannins. Of the phenolic aldehydes tested, sinapaldehyde, coniferaldehyde, p-hydroxybenzaldehyde, 3,4- dihydroxybenzaldehyde and 3,4,5-trihydroxybenzaldehyde significantly inhibited the growth of O. oeni VF, while vanillin and syringaldehyde had no effect at the concentrations tested. Lact. hilgardii 5 was only inhibited by sinapaldehyde and coniferaldehyde. Among the flavonoids, quercetin and kaempferol exerted an inhibitory effect especially on O. oeni VF. Myricetin and the flavan-3-ols studied (catechin and epicatechin) did not affect considerably the growth of both strains. Condensed tannins (particularly tetramers and pentamers) were found to strongly affect cell viability, especially in the case of O.
    [Show full text]
  • Château Simone
    Château Simone This historic estate, situated in the hills just south of Aix-en-Provence, has been in the hands of four generations of the Rougier family since 1830 and holds a virtual monopoly on the appellation of Palette. The property totals 120 hectares, with 28 under vine, of which 23 qualify for the Palette AOC. Its vineyards sit on limestone soils at elevations between 500 and 750 feet on the slopes of the Montaiguet, whose special microclimate is influenced by the encircling pine forests, the mass of the Mont Sainte-Victoire, and the Arc River. The vineyards were reconstituted after phylloxera and many vines are over a century old. In an industry that moves quicker than ever and presents ever-increasing novelty, an estate like Simone is an anchor of meaning and a lens into Provence's patrimony. Viticulture: • Farming: Ecocert Organic Certification Pending. Viticulture has always been practicing organic. • Treatments : No herbicides, chemical fertilizers, or synthetic treatments • Ploughing: Extensive ploughing and working of the soil by tractor. • Soils: Limestone Scree • Vines: Head-trained vines, many over 100-years old, that are replanted on a vine-by-vine basis to maintain a healthy vineyard • Yields: Old vines and extensive debudding lower yields and eliminate the need for a green harvest. • Harvest: Entirely manual harvest, grapes sorted in the vineyard and sorted again in the cellar • Purchasing: Always entirely estate fruit Vinification: Aging: • Fermentation: All wines are fermented spontaneously in large • Élevage: Palette wines are stored in foudres for 18 months; wooden foudres with temperature control for 2 weeks. red and white wines spend an additional year in neutral barrel.
    [Show full text]
  • Properties of Acids and Bases
    GREEN CHEMISTRY LABORATORY MANUAL Lab 22 Properties of Acids and Bases TN Standard 4.2: The student will investigate the characteristics of acids and bases. Have you ever brushed your teeth and then drank a glass of orange juice? hat do you taste when you brush your teeth and drink orange juice afterwards. Yuck! It leaves a really bad taste in your mouth, but why? Orange juice and toothpaste by themselves taste good. But the terrible taste W results because an acid/base reaction is going on in your mouth. Orange juice is a weak acid and the toothpaste is a weak base. When they are placed together they neutralize each other and produce a product that is unpleasant to taste. How do you determine what is an acid and what is a base? In this lab we will discover how to distinguish between acids and bases. Introduction Two very important classes of compounds are acids and bases. But what exactly makes them different? There are differences in definition, physical differences, and reaction differences. According to the Arrhenius definition, acids ionize in water to + produce a hydronium ion (H3O ), and bases dissociate in water to produce hydroxide ion (OH -). Physical differences can be detected by the senses, including taste and touch. Acids have a sour or tart taste and can produce a stinging sensation to broken skin. For example, if you have ever tasted a lemon, it can often result in a sour face. Bases have a bitter taste and a slippery feel. Soap and many cleaning products are bases.
    [Show full text]
  • Q1.Sodium Carbonate Reacts with Dilute Hydrochloric Acid
    Q1.Sodium carbonate reacts with dilute hydrochloric acid: Na2CO3 + 2HCl → 2NaCl + H2O + CO2 A student investigated the volume of carbon dioxide produced when different masses of sodium car- bonate were reacted with dilute hydrochloric acid. This is the method used. 1. Place a known mass of sodium carbonate in a conical flask. 2. Measure 10 cm3 of dilute hydrochloric acid using a measuring cylinder. 3. Pour the acid into the conical flask. 4. Place a bung in the flask and collect the gas until the reaction is complete. (a) The student set up the apparatus as shown in the figure below. Identify the error in the way the student set up the apparatus. Describe what would happen if the student used the apparatus shown. (2) (b) The student corrected the error. The student’s results are shown in the table below. Mass of sodium carbonate Volume of carbon dioxide gas 3 in g in cm 0.07 16.0 0.12 27.5 0.23 52.0 0.29 12.5 0.34 77.0 0.54 95.0 0.59 95.0 0.65 95.0 The result for 0.29 g of sodium carbonate is anomalous. Suggest what may have happened to cause this anomalous result. (1) (c) Why does the volume of carbon dioxide collected stop increasing at 95.0 cm3? (1) (d) What further work could the student do to be more certain about the minimum mass of sodium M1.(a) (delivery) tube sticks into the acid 1 the acid would go into the water or the acid would leave the flask or go up the delivery tube ignore no gas collected 1 (b) any one from: • bung not put in firmly / properly • gas lost before bung put in • leak from tube 1 (c) all of the acid has reacted 1 (d) take more readings in range 0.34 g to 0.54 g 1 take more readings is insufficient ignore repeat 1 (e) The carbon dioxide was collected at room temperature and pressure.
    [Show full text]
  • Genome and Pangenome Analysis of Lactobacillus Hilgardii FLUB—A New Strain Isolated from Mead
    International Journal of Molecular Sciences Article Genome and Pangenome Analysis of Lactobacillus hilgardii FLUB—A New Strain Isolated from Mead Klaudia Gustaw 1,* , Piotr Koper 2,* , Magdalena Polak-Berecka 1 , Kamila Rachwał 1, Katarzyna Skrzypczak 3 and Adam Wa´sko 1 1 Department of Biotechnology, Microbiology and Human Nutrition, Faculty of Food Science and Biotechnology, University of Life Sciences in Lublin, Skromna 8, 20-704 Lublin, Poland; [email protected] (M.P.-B.); [email protected] (K.R.); [email protected] (A.W.) 2 Department of Genetics and Microbiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland 3 Department of Fruits, Vegetables and Mushrooms Technology, Faculty of Food Science and Biotechnology, University of Life Sciences in Lublin, Skromna 8, 20-704 Lublin, Poland; [email protected] * Correspondence: [email protected] (K.G.); [email protected] (P.K.) Abstract: The production of mead holds great value for the Polish liquor industry, which is why the bacterium that spoils mead has become an object of concern and scientific interest. This article describes, for the first time, Lactobacillus hilgardii FLUB newly isolated from mead, as a mead spoilage bacteria. Whole genome sequencing of L. hilgardii FLUB revealed a 3 Mbp chromosome and five plasmids, which is the largest reported genome of this species. An extensive phylogenetic analysis and digital DNA-DNA hybridization confirmed the membership of the strain in the L. hilgardii species. The genome of L. hilgardii FLUB encodes 3043 genes, 2871 of which are protein coding sequences, Citation: Gustaw, K.; Koper, P.; 79 code for RNA, and 93 are pseudogenes.
    [Show full text]
  • Ph Indicators Analysis Within Seconds Ph Indicator Strips
    pH Indicators Analysis within Seconds pH Indicator Strips Economic in price In practice, it is normally quite sufficient to be able to measure pH in full units or in tenths of a unit. For this type of determination, as carried out in many laboratories, our various types of indicator paper, strips and liquids have proven themselves over many years. pH indicator paper has been on the market for decades in booklet and roll form. However, these forms are being more and more replaced by the more modern strip form (see next page). Indicator paper consists of high quality filter paper impregnated with indicator or indicator mixture. Order No. Designation pH range Graduation Roll length/ The table alongside shows the (*transition range) (pH units) No. of strips various types of booklet and rolls available Rolls 1.09565.0001 pH box 0.5 -13.0 0.5 3 x 4.8 m 1.09568.0001 Refill rolls, pH 0.5-5.0 0.5 - 5.0 0.5 6 x 4.8 m 1.09569.0001 Refill rolls, pH 5.5-9.0 5.5 - 9.0 0.5 6 x 4.8 m 1.09570.0001 Refill rolls, pH 9.5-13.0 9.5 -13.0 0.5 6 x 4.8 m 1.10962.0001 Universal indicator 1 -14.0 1 6 x 4.8 m 1.10232.0001 Refill rolls 6 x 4.8 m 1.09526.0001 Universal indicator 1 -10.0 1 6 x 4.8 m 1.09527.0001 Refill rolls 6 x 4.8 m 1.09560.0001 Acilit 0.5 - 5.0 0.5 6 x 4.8 m 1.09568.0001 Refill rolls 6 x 4.8 m 1.09564.0001 Neutralit 5.5 - 9.0 0.5 6 x 4.8 m 1.09569.0001 Refill rolls 6 x 4.8 m 1.09562.0001 Alkalit 9.5 -13.0 0.5 6 x 4.8 m 1.09570.0001 Refill rolls 6 x 4.8 m 1.09486.0001 Litmus paper, blue pH <7 red / >7 blue* 6 x 4.8 m 1.09489.0001 Litmus paper, red
    [Show full text]