The effect of increased yeast alchohol acetyltransferase and esterase activity on the flavour profiles of wine and distillates
Date
2006
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Abstract
The fruity odours of wine are largely derived from the synthesis of esters and higher alcohols during yeast fermentation. The ATF1- and ATF2-encoded alcohol acetyltransferases of S. cerevisiae are responsible for the synthesis of ethyl acetate and isoamyl acetate esters, while the EHT1-encoded ethanol hexanoyl transferase is responsible for synthesizing ethyl caproate. However, esters such as these might be degraded by the IAH1-encoded esterase. The objectives of this study were: (a) to overexpress the genes encoding ester-synthesizing and ester-degrading enzymes in wine yeast; (b) to prepare Colombard table wines and base wines for distillation using these modified strains; and (c) to analyse and compare the ester concentrations and aroma profiles of these wines and distillates. The overexpression of ATF1 significantly increased the concentrations of ethyl acetate, isoamyl acetate, 2-phenylethyl acetate and ethyl caproate, while the overexpression of ATF2 affected the concentrations of ethyl acetate and isoamyl acetate to a lesser degree. The overexpression of IAH1 resulted in a significant decrease in ethyl acetate, isoamyl acetate, hexyl acetate and 2-phenylethyl acetate. The overexpression of EHT1 resulted in a marked increase in ethyl caproate, ethyl caprylate and ethyl caprate. The flavour profile of the wines and distillates prepared using the modified strains were also significantly altered as indicated by formal sensory analysis. This study offers prospects for the development of wine yeast starter strains with optimized ester-producing capability that could assist winemakers in their effort to consistently produce wine and distillates such as brandy to definable flavour specifications and styles. Copyright © 2006 John Wiley & Sons, Ltd.
Description
Keywords
acetic acid 2 phenylethyl ester, acetic acid ethyl ester, acetic acid hexyl ester, activating transcription factor 1, activating transcription factor 2, acyltransferase, alcohol acyltransferase, caproic acid ethyl ester, caprylic acid ethyl ester, decanoic acid ethyl ester, ester derivative, esterase, fungal enzyme, isopentyl acetate, unclassified drug, article, controlled study, distillation, enzyme activity, fermentation, flavor, fungal strain, gene overexpression, nonhuman, priority journal, Saccharomyces cerevisiae, synthesis, viniculture, Acetyltransferases, Blotting, Southern, Carboxylic Ester Hydrolases, DNA, Fungal, Esters, Fermentation, Odors, Proteins, Recombinant Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Taste, Transformation, Genetic, Wine
Citation
Yeast
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9
23
9