DOCSLIB.ORG

This Electronic Thesis Or Dissertation Has Been Downloaded from Explore Bristol Research

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
This Electronic Thesis Or Dissertation Has Been Downloaded from Explore Bristol Research This electronic thesis or dissertation has been downloaded from Explore Bristol Research, http://research-information.bristol.ac.uk Author: Beech, F. W Title: The incidence and classification of cider yeasts General rights Access to the thesis is subject to the Creative Commons Attribution - NonCommercial-No Derivatives 4.0 International Public License. A copy of this may be found at https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode This license sets out your rights and the restrictions that apply to your access to the thesis so it is important you read this before proceeding. Take down policy Some pages of this thesis may have been removed for copyright restrictions prior to having it been deposited in Explore Bristol Research. However, if you have discovered material within the thesis that you consider to be unlawful e.g. breaches of copyright (either yours or that of a third party) or any other law, including but not limited to those relating to patent, trademark, confidentiality, data protection, obscenity, defamation, libel, then please contact [email protected] and include the following information in your message: •Your contact details •Bibliographic details for the item, including a URL •An outline nature of the complaint Your claim will be investigated and, where appropriate, the item in question will be removed from public view as soon as possible. _' .: THE INCIDENcE AND CLASSIFICATION OF CIDER YEASTS by F.W.BEECH Thesis submitted for the Degree of Doctor of Philosophy of the University of Bristol MARCH 1957 CONTAINS PULLOUTS CONTENTS Page. IN'mOIlJCTION. 1 SECTION I. THE ISOLATION OF YEASTS FROM APPLE JUICES ANDCIDERS. Introduction. 6 1. Preparation of a Standard. Medium. (i) Literature Review. 8 (ii) Mediumused. 10 2. Preparation of Differential Media. (i) Literature Review. 11 (a) Antibiotics. .. 11 (b) Inhibitory compoundsother than antibiotics. 18 (ii) Experimental Work. 24- Compcundstested. 24 Test Organisms. 24- Medium. 27 Preparation ot the Inocula. 27 F~eparation ot Test Plates. 28 Inoculation ot Plates. 28 Incubation and Observation of Plates. 29 (iii) Results. 29 (a) Canpcunds suitable for the selective isolation of yeasts. 29 (b) Ccmpcundssuitable for the selective isolation of lactic and acetic acid bacteria. 32 (c) Compoundssuitable for the isolation of certain yeast species. 33 (d) Compcundssuitable for suppressing moulds. 33 Effect of solvents. 34 . Compoundsused for isolation media. 35 (iv) Discussion. 36 3. Sampling and Counting. (i) Idterature Review. 37 Fruit. , 37 Juices and Ciders. 38 (ii) Methods Used. 39 Sampling• . Fruit. 39 Juices. 40 Ciders. 40 Counting. U (iii) Results. 42. 4. Purification and Storage. Purification. 43 [Storage. (i) Literature Review. 44 (ii) Methods Used. 47 - i - Page 5. Sources of Yeast Isolates. SECTIONII. THEIDENTIFICATIONOF lEAST ISOLATES. Introduction. .50 Basal Media. .50 Inocula. 51 Estimation of Yeast Growth. 51 . A. IDENTIFICATIONOF SProlES. 1. Sporulation. (i) Literature Review. 52 (ii) Methods Used. 55 Media. 55 Inoculation of Sporulation Media. 58 Observe.tions. 58 (iii) Results. 59 (iv) Discussion. 60 2. MOIllhology.in Liquid Culture. 62 (i) Experimental Work. 63 (ii) Method Used. 64- 3. Morrhology on Solid Media•. (a) Appearance of the streak culture. 65 (b) Formation of pseudomycelia. 65 4. Fennentation of Standard Sugars. (i! Literature Review. 67 (ii Experimental Work. 69 (11i Method Used. 70 (i v Results. 72 (v Discu ssion. 72 5. Assimilation of Standard Sugars. 74- (i~ Literature Review. 74 (ii :Method.Used. 75 (iii Results. 77 (i v Discussion. 77 6. Assimilation of Ethanol as Sole Source of Carbon. (i) Method Used. 7. Hydrolysis of the Gl,ycosides, aesculin and arbutin. (i) Literature Review. 79 (iil Experimental Work. 80 . (iii :Method.Used. 82 , (iv Results. 82 (v) Discussion. 82 8. Assimilation of Nitrate. (i) Method Used. 84 (ll) Results. 85 - ii - Page 9. Formation of Pigments. (i) Literature Review. 85 ajCarotenoid Pigments. 86 bIron-containing Pi.gment s , 87 c Pigment produced as a result of nutrient ! deficiencie s. 88 (d) Pigment produced by mutants. 89 (ii) MethodUsed. 89 (iii) Results •. 91 10. Fonnation of Starch. (il Idterature Review. 94 (ii MethodUsed. 94 (iii Results. 96 11. Formation of Acid fran Glllcose. (il Idterature Review. 96 (ii MethodUsed. 97 (iii Results. 98 (iv Discussion. 99 B. IDENTIFICATION OF STRAINS OF lEAST SPECIES. 101 1. Formation of Giant Colonies. 101 (i) };IethodUsed. 101 2. Flocculation. (i) MethodUsed. 102 3. Assimilation of Single Carbon Canpounds. (i) Literature RevieW. 103 (ii} Experimental Work. 104 (iii MethodUsed. 105 (iv Results. 107 4. Assimilation of Single AminoAcids. (il Literature Review. 107 (ii Experimental Work. 108 (iii MethodUsed. llO 5. Vitamin Reqairements. il Literature Review. ll2 « 1i Experimental Work. 114 (iii Method Used. 115 6. Formation.~f Ammonia. (1) Experimental Work. ll8 (U) MethodUsed. 119 C. NEW BIOCIIE1JICAL TESTS APPLICABLE TO lEAST CLASSIFICATION. 1. Fomation of acids fioan glucose. (i) Experimental Work. 122 (ii) Results. 123 - iii - Page 2. Production of amino acids from amnoniumsulphate. (i) Experimental Work. 124- (ii) Results. 125 3. Classification of yeasts according to their "antibiotic" spectra. 126 AH'ENDIX I. Composition of Difeo dehydrated media. 127 SECTION III. CLASSIFICATION OF YEAST ISOLA.TES. Intrcxllction. 128 1. The use of pInched cards for collating results. 132 2. Results. 135 Gemls Saccharanyces. 138 Genus Pichia. 144 Genus Debaryan"yces. 147 Genus Hanseniaspora. 149 Genus Cryptococcus. 150 Genus Torulopsis. 155 Genus Brettenomyces. " 161 Genus Candida. 168 Gems K1oeckera. 182 Genus Rhodotoru1a. 183 3. Discussion. 187 SECTION IV. DISTRIIDTION OF YEASTS ISOLATED FROM .APPLE JUICES ANDClIERS. 1. Literature Review. 190 2. Results. 193 (i) Yeasts present on the fruit. 193 (ii) Yeasts isolated 'from juices and ciders processed on pilot-plant equipnent. (a) Juices. 195 (b) During fermentation. 196 (iii) Yeasts in juices and ciders processed an large scale e~ipment. (a) Juice. 199 (b) Effect of cider-making processes on the yeast flora. 200 (c) Yeasts developing during laboratory tests based on ciders processed on the large scale. 203 3. Practical applications in Cider-l-!ald.ng. 205 SJMM.ARY. 210 ACKNOWLEDGl!}.lENTS. 214 BIBLIOGRAPHY. 215 .AFISNDIX II. 232 - iv - INTRODUCTION Until the early 1920's, cider-making in Englandwas confined mainly to the farms of the West Cruntry where empirical methodswere employed. Now, most of the cider produced canes fran factories where the older methodshave proved ina.deqy.atefor maintaining cQ'ltrolled fermentations and for the production of ciders of optinllmvintage quality. This problemwas recognised , in the past by many Continental research workers, most of whansought improve-. mentby the use of pure yeast cultures, althrugh the actuel. methodemployed in each cruntry has also been conditioned by the type of fruit available and by the national. palate. Thus, in Germany, the apples are high in acid and contain little tannin; a dry cider is preferred, so that sane extra treatment must be given to impart a better flavcur to the final product. It is not surprising, therefofie, to find that pure yeast cultures -wereused for cider- making :fran an early date. Evenin 1903, Alwoodnoted that nearly all the large cider factories used the yeast cultures sent cut regularly fran the Royal Panological. School at Geisenheim. The cultures were added to the freshly expressed juices that were then allowed to ferment rapidly at 15-l8°C, racked at dryness and stored at low temperature for several. months. This treatment produceda vinous type of beverage more akin to a light white wine. Noattempt wasmadeto control the natural flora, but in later years (Charley, 1937) the juices wereusually centrifuged or, occasionally, pasteurised before inoculation. TheSwiss, whohave similar sorts of apples, use essentially the samemethods, sanetimes ccntrolling the natural flora with Sllplnlr dioxide and adding the yeast culture several hcurs after su1phiting (Challinor, 1948). In France, the apples used for c1der-makingare totally different in character, being low in acid and relatively rich in t~. ]urther, a rather sweet cider is preferred, and, since artificial. sweetening'is forbidden by law, attempts have been madeto preserve sane' of the natural Slgar of the original juice. Consequently, althcugh such workers as Kayser (1890) and Dienert (1896) isolated yeasts fran ciders, their main object was to find those yeasts incapable of fermenting sucrose or possessing poor powersof fermentation. Attemptsmadeto use such isolates under factory ccnditims proved abortive. If the yeasts were added in large C}!la.ntities, in order to - 2 - overgrow the natural flora of the juice, the fennentation was too rapid and uncontrollable. Attempts to sterilise the fresh juice before yeasting also proved unsatisfactory, since the pasteurising plant then in use gave a persistent "cooked" flavour to the juice (Warcollier, 1928) and, in the absence of acid-resisting metals, often introduced unpleasant flavours from copper-and iran salts. These difficulties might have been overcome,but the exaggerated claims of some of the early exponents of the use of prre yeasts 'Werenot substantiated (Warcollier, 1928). The method thus fell into disuse except for the rapid fennentation of panace extracts destined for distillation as fUel alcohol (Auclair, 1955). Instead, the rate of fermentation was controlled (a) by reducing the nitrogen content of the juice
Load more

Recommended publications
  • Perfil Fermentativo De Uma Linhagem De Dekkera Bruxellensis Van Der Walt (1964)
    Reis, Alexandre Libanio – Perfil Fermentativo de uma linhagem de Dekkera bruxellensis van der Walt (1964)... PERFIL FERMENTATIVO DE UMA LINHAGEM DE Dekkera bruxellensis van der Walt (1964) A PARTIR DE HIDROLISADOS LIGNOCELULÓSICOS E SUAS IMPLICAÇÕES NA PRODUÇÃO DE ETANOL DE SEGUNDA GERAÇÃO ALEXANDRE LIBANIO SILVA REIS RECIFE Março/2014 Reis, Alexandre Libanio – Perfil Fermentativo de uma linhagem de Dekkera bruxellensis van der Walt (1964)... UNIVERSIDADE FEDERAL DE PERNAMBUCO CENTRO DE CIÊNCIAS BIOLÓGICAS DEPARTAMENTO DE MICOLOGIA PROGRAMA DE PÓS-GRADUAÇÃO EM BIOLOGIA DE FUNGOS PERFIL FERMENTATIVO DE UMA LINHAGEM DE Dekkera bruxellensis van der Walt (1964) A PARTIR DE HIDROLISADOS LIGNOCELULÓSICOS E SUAS IMPLICAÇÕES NA PRODUÇÃO DE ETANOL DE SEGUNDA GERAÇÃO Tese apresentada ao Programa de Pós-Graduação em Biologia de Fungos do Departamento de Micologia do Centro de Ciências Biológicas da Universidade Federal de Pernambuco, como parte dos requisitos para a obtenção do título de Doutor em Biologia de Fungos. Micologia Aplicada Alexandre Libanio Silva Reis Orientador: Marcos Antônio de Morais Júnior, Dr. RECIFE Março/2014 Reis, Alexandre Libanio – Perfil Fermentativo de uma linhagem de Dekkera bruxellensis van der Walt (1964)... Reis, Alexandre Libanio – Perfil Fermentativo de uma linhagem de Dekkera bruxellensis van der Walt (1964)... PERFIL FERMENTATIVO DE UMA LINHAGEM DE Dekkera bruxellensis van der Walt (1964) A PARTIR DE HIDROLISADOS LIGNOCELULÓSICOS E SUAS IMPLICAÇÕES NA PRODUÇÃO DE ETANOL DE SEGUNDA GERAÇÃO ALEXANDRE LIBANIO SILVA REIS Data da defesa: 14 de Março de 2014 COMISSÃO EXAMINADORA MEMBROS TITULARES Dr. Marcos Antônio de Morais Júnior – (Orientador) Universidade Federal de Pernambuco – Departamento de Genética Dra. Cristina Maria de Souza Motta – Examinadora Interna Universidade Federal de Pernambuco – Departamento de Micologia Dr.
    [Show full text]
  • Alternative Formats If You Require This Document in an Alternative Format, Please Contact: [email protected]
    University of Bath PHD Species-specific PCR primers for the rapid and reliable identification of yeast species Harrison, Elizabeth Award date: 2006 Awarding institution: University of Bath Link to publication Alternative formats If you require this document in an alternative format, please contact: [email protected] General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Download date: 08. Oct. 2021 Species-specific PCR primers for the rapid and reliable identification of yeast species Volume 1 of 1 Elizabeth Harrison A thesis submitted for the degree of Doctor of Philosophy University of Bath Department of Biology and Biochemistry June 2006 COPYRIGHT Attention is drawn to the fact that copyright of this thesis rests with its author. This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without the prior written consent of the author.
    [Show full text]
  • Brettanomyces Yeasts — from Spoilage Organisms to Valuable Contributors to Industrial Fermentations
    International Journal of Food Microbiology 206 (2015) 24–38 Contents lists available at ScienceDirect International Journal of Food Microbiology journal homepage: www.elsevier.com/locate/ijfoodmicro Brettanomyces yeasts — From spoilage organisms to valuable contributors to industrial fermentations Jan Steensels a,b, Luk Daenen c, Philippe Malcorps c, Guy Derdelinckx d, Hubert Verachtert d, Kevin J. Verstrepen a,b,⁎ a Laboratory for Genetics and Genomics, Department of Microbial and Molecular Systems (M2S), Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium b Laboratory for Systems Biology, VIB, Bio-Incubator, Gaston Geenslaan 1, 3001 Leuven, Belgium c AB-InBev SA/NV, Brouwerijplein 1, B-3000 Leuven, Belgium d Centre for Food and Microbial Technology, Department of Microbial and Molecular Systems (M2S), LFoRCe, KU Leuven, Kasteelpark Arenberg 33, 3001 Leuven, Belgium article info abstract Article history: Ever since the introduction of controlled fermentation processes, alcoholic fermentations and Saccharomyces Received 24 November 2014 cerevisiae starter cultures proved to be a match made in heaven. The ability of S. cerevisiae to produce and with- Received in revised form 23 March 2015 stand high ethanol concentrations, its pleasant flavour profile and the absence of health-threatening toxin Accepted 3 April 2015 production are only a few of the features that make it the ideal alcoholic fermentation organism. However, in cer- Available online 8 April 2015 tain conditions or for certain specific fermentation processes, the physiological boundaries of this species limit its Keywords: applicability. Therefore, there is currently a strong interest in non-Saccharomyces (or non-conventional) yeasts fi β-Glycosidase with peculiar features able to replace or accompany S.
    [Show full text]
  • Perfil Fermentativo De Uma Linhagem De Dekkera Bruxellensis Van Der Walt (1964)
    Reis, Alexandre Libanio – Perfil Fermentativo de uma linhagem de Dekkera bruxellensis van der Walt (1964)... PERFIL FERMENTATIVO DE UMA LINHAGEM DE Dekkera bruxellensis van der Walt (1964) A PARTIR DE HIDROLISADOS LIGNOCELULÓSICOS E SUAS IMPLICAÇÕES NA PRODUÇÃO DE ETANOL DE SEGUNDA GERAÇÃO ALEXANDRE LIBANIO SILVA REIS RECIFE Março/2014 Reis, Alexandre Libanio – Perfil Fermentativo de uma linhagem de Dekkera bruxellensis van der Walt (1964)... UNIVERSIDADE FEDERAL DE PERNAMBUCO CENTRO DE CIÊNCIAS BIOLÓGICAS DEPARTAMENTO DE MICOLOGIA PROGRAMA DE PÓS-GRADUAÇÃO EM BIOLOGIA DE FUNGOS PERFIL FERMENTATIVO DE UMA LINHAGEM DE Dekkera bruxellensis van der Walt (1964) A PARTIR DE HIDROLISADOS LIGNOCELULÓSICOS E SUAS IMPLICAÇÕES NA PRODUÇÃO DE ETANOL DE SEGUNDA GERAÇÃO Tese apresentada ao Programa de Pós-Graduação em Biologia de Fungos do Departamento de Micologia do Centro de Ciências Biológicas da Universidade Federal de Pernambuco, como parte dos requisitos para a obtenção do título de Doutor em Biologia de Fungos. Micologia Aplicada Alexandre Libanio Silva Reis Orientador: Marcos Antônio de Morais Júnior, Dr. RECIFE Março/2014 Reis, Alexandre Libanio – Perfil Fermentativo de uma linhagem de Dekkera bruxellensis van der Walt (1964)... Catalogação na fonte Elaine Barroso CRB 1728 Reis, Alexandre Libanio Silva Perfil fermentativo de uma linhagem de Dekkera bruxellensis van der Walt (1964) a partir de hidrolisados lignocelulósicos e suas implicações na produção de etanol de segunda geração/ Alexandre Libanio Silva Reis. – Recife: O Autor, 2014. 94 folhas : il., fig., tab. Orientador: Marcos Antonio de Morais Júnior Tese (doutorado) – Universidade Federal de Pernambuco. Biologia de Fungos, 2014. Inclui bibliografia 1. Leveduras (fungos) 2. Álcool 3. Fermentação I. Título. 579.562 CDD (22.ed.) UFPE/CCB-2015-07 Reis, Alexandre Libanio – Perfil Fermentativo de uma linhagem de Dekkera bruxellensis van der Walt (1964)..
    [Show full text]
  • Nutritional Requirements and Survival of the Red Wine Spoilage Yeast Brettanomyces Bruxellensis
    Nutritional requirements and survival of the red wine spoilage yeast Brettanomyces bruxellensis by Brendan Daniel Smith Thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Stellenbosch University Department of Viticulture and Oenology, Faculty of AgriSciences Supervisor: Dr Benoit Divol December 2016 Stellenbosch University https://scholar.sun.ac.za Declaration By submitting this thesis electronically, I declare that the entirety of the work contained therein is my own, original work, that I am the sole author thereof (save to the extent explicitly otherwise stated), that reproduction and publication thereof by Stellenbosch University will not infringe any third party rights and that I have not previously in its entirety or in part submitted it for obtaining any qualification. Date: December 2016 Copyright © 2016 Stellenbosch University All rights reserved Stellenbosch University https://scholar.sun.ac.za Summary Brettanomyces bruxellensis is a red wine spoilage yeast that plagues the wine industry. It facilitates the formation of compounds such as volatile phenols, which impart negative aromas in red wines. Its ability to survive in wine through adaptations to various stressors (e.g. high ethanol and sulphur dioxide concentrations, low pH) have made it the subject of several studies. These studies aim to understand its biology (and in particular its nutrient requirements) and its survival mechanisms in general, as well as to detect and enumerate it accurately and to eliminate it. Nevertheless, literature on the subject is at certain times contradictory with regard to the nutritional needs of this yeast. The survival of this yeast for extended periods of time lead us to question how it is so well adapted to this deficient environment.
    [Show full text]
  • Università Degli Studi Di Napoli Federico II Facoltà Di Agraria
    Università degli Studi di Napoli Federico II Facoltà di Agraria Corso di Laurea in Viticoltura ed Enologia TESI DI LAUREA I lieviti Brettanomyces: da organismi alterativi a preziosi collaboratori delle fermentazioni industriali Relatore Candidato Prof. G. Blaiotta Leone Francesco Matr. N03/248 ANNO ACCADEMICO 2014/2015 INDICE Riassunto ................................................................................................................... 3 1. Introduzione .............................................................................................................. 3 2. Tassonomia di Brettanomyces ................................................................................... 5 3. Il Brettanomyces: genoma e fenotipo ........................................................................ 6 3.1 Genoma di Brettanomyces ................................................................................... 6 3.2 Fenotipo di Brettanomyces................................................................................... 8 3.2.1 La crescita e la fermentazione di Brettanomyces ......................................... 8 3.2.2 Produzione di sapori del Brettanomyces ................................................... 14 3.3 Sicurezza microbica di Brettanomyces ............................................................... 19 3.3.1 La produzione di ammine biogene ............................................................ 20 3.3.2 Resistenza alla Cicloesimide .................................................................... 21
    [Show full text]
  • The World of Brettanomyces
    THE WORLD OF BRETTANOMYCES By Peter Perrecone WHAT IS BRETTANOMYCES? • Brettanomyces is a non-spore forming genus of yeast in the family Saccharomycetaceae, and is often called "Brett". The genus name Dekkera is used interchangeably with Brettanomyces, as it describes the spore forming form of the yeasts.. Brettanomyces is important to both the brewing and wine industries due to the sensory compounds it produces. • In the wild, Brettanomyces lives on the skins of fruit. The strain Brettanomyces claussenii was discovered at the Carlsberg brewery in 1904 by N. Hjelte Claussen, who was investigating it as a cause of spoilage in English ales. The term Brettanomyces comes from the Greek word "British fungus." SENSORY COMPOUNDS The compounds responsible for contributing certain sensory characters to wine/beer are; 4-ethylphenol: Band-aids, barnyard, horse stable, antiseptic 4-ethylguaiacol: Bacon, spice, cloves, smoky isovaleric acid: Sweaty saddle, cheese, rancidity BRETTANOMYCES AND BEER In most beer styles Brettanomyces is viewed as a contaminant and the characteristics it imparts are considered unwelcome "off-flavours." However, in some styles, particularly certain traditional Belgian ales, it is appreciated and encouraged. Lambic and gueuze owe their unique flavour profiles to Brettanomyces, as do wild yeast saison or farmhouse styles; and it is also found in Oud Bruin and Flanders red ale. COMMERCIAL EXAMPLES Commercial examples of these styles include Cantillon Rosé de Gambrinus, Liefmans Brown Ale, Rodenbach Grand Cru, and Duchesse de Bourgogne. The Orval Trappist monastery is unique in crafting the only Trappist beer with Brettanomyces characteristics. In Orval's case, the brewers add the yeast to the beer at bottling.
    [Show full text]
  • Physiology and Metabolism of Dekkera/Brettanomyces Yeast in Relation to Mousy Taint Production
    ?o'ì'c{g t, i{ Physiology and metabolism of Dekkera/Brettanomyces yeast in relation to mousy taint production by PAUL R. GRBIN BSc. (Adel.), Grad. Dip. Wine (Roseworthy) A thesis submitted for the degree of Doctor of Philosophy in the Faculty of Agricultural and Natural Resources Sciences Department of Horticulture, Viticulture, and Oenology The Univeróity of Raelaide March 1998 'a flavour often left on the tongue as an aftertaste, reminiscent of the odour from mice kept in a confined space' (Erckmann, 1898) Table of Contents SUMMARY 1V DECLARATION .............. vlll ACKNO\ilLEDGMENTS IX ABBREYIATIONS.. x CHAPTER 1 Introduction and Literature Review............ .1 1.1 Introduction .1 1.2 The chemical nature of mousy taint............. 4 1.2. I 2-ethyltetahydropyridine 4 1.2.2 2-acetyltetrahyd¡opyridine ...... 4 1.2.3 2-acetylpynoline 7 1.3 Dekkeral Brettanomyces and beverage production ... 8 1.3.I T axonomy of D ekkeral BrettsnomJ)ces I l.3.2DekkeralBrettanomltcesspoilageotherfh?nmousytaint.. t2 l.3.3Positiveconfübutionsof De.kkgral&rettanomycesinbevetageproduction............ 15 1.3.4 Incidence of Dekkeral Brettanom]¡ces in wine production l6 1 .3 .5 D e kker a I B r ett an o m]¡ c e s and mottsy taint pro duction .. .' ., t7 1.4 Factors affecting mousy taint production by DekkeralBrettanomyces........ l8 1.4. I Lvsine catabolism ..... 18 1.4.2 Ethanol and mous]¡ taint .....25 1.4.3 The role of air/ox)¡gen... .....26 1.5 Proposed pathway for mousy taint production .....28 1.6 Research aims ..... 30 CHAPTER 2 Method Development for the Analysis of Mousy Taint Compounds 32 2.1 Introduction 32 2.2 Materials and methods.......
    [Show full text]