Biological Demalication and Deacetification of Musts and Wines: Can Wine Yeasts Make the Wine Taste Better?

Alice Vilela

doi:10.3390/fermentation3040051

Abstract

Grape musts sometimes reveal excess acidity. An excessive amount of organic acids negatively affect wine yeasts and yeast fermentation, and the obtained wines are characterized by an inappropriate balance between sweetness, acidity or sourness, and flavor/aroma components. An appropriate acidity, pleasant to the palate is more difficult to achieve in wines that have high acidity due to an excess of malic acid, because the Saccharomyces species in general, cannot effectively degrade malic acid during alcoholic fermentation. One approach to solving this problem is biological deacidification by lactic acid bacteria or non-Saccharomyces yeasts, like Schizosaccharomyces pombe that show the ability to degrade L-malic acid. Excessive volatile acidity in wine is also a problem in the wine industry. The use of free or immobilized Saccharomyces cells has been studied to solve both these problems since these yeasts are wine yeasts that show a good balance between taste/flavor and aromatic compounds during alcoholic fermentation. The aim of this review is to give some insights into the use of Saccharomyces cerevisiae strains to perform biological demalication (malic acid degradation) and deacetification (reduction of volatile acidity) of wine in an attempt to better understand their biochemistry and enological features.

Highlights

General IntroductionA balanced wine in terms of flavor should be the goal of every winemaker. Much is known about how taste components, such as acidity, sweetness, savoriness (”umami”) and alcohol can work together in coordination or discord on the palate [1,2,3]
Acetic acid can be formed as a byproduct of alcoholic fermentation or as a byproduct of the metabolism of acetic and lactic acid bacteria, which can metabolize residual sugars to increase volatile acidity
We have studied an empirical biological deacidification process, previously discussed by Ribéreau-Gayon et al [14], that aims to lower the volatile acidity of wines

Summary

General Introduction

A balanced wine in terms of flavor should be the goal of every winemaker. Much is known about how taste components, such as acidity, sweetness, savoriness (”umami”) and alcohol can work together in coordination or discord on the palate [1,2,3]. Yeast has the capability to consume malic acid by converting it into ethanol through malo-ethanolic deacidification This microbiological process can cause a small increase in the wine’s alcohol content; but, sometimes this is preferred over the aroma and flavor of lactic acid produced by lactic acid bacteria. S. pombe totally consumed the malic acid that was present, while Lachancea thermotolerans produced lactic acid This process avoided the use of LAB strains to perform malolactic fermentation, achieving microbiological stabilization of the wine. We have studied an empirical biological deacidification process, previously discussed by Ribéreau-Gayon et al [14], that aims to lower the volatile acidity of wines This process consists in refermenting the acidic wines by mixing them with marc from a finished wine fermentation, freshly crushed grapes or musts.

Overview

The Demalication Activity of Saccharomyces Strains

Schematic representation of the actions

Findings

Final Remarks