Exploitation of technological variability among wild non-Saccharomyces yeasts to select mixed starters for the production of low alcohol wines

A Grazia,P Romano,R Pietrafesa,G Siesto,A Capece,A Pietrafesa,P Roca

doi:10.1051/bioconf/20191502031

Abstract

Increase of the sugar content in grape must, and consequently, alcohol levels in wine are some of the principal problems affecting the winemaking industry. High alcohol content can compromise wine quality, creating sensory imbalances, as well as decreasing the perception of some flavors. The technological approaches proposed at this aim, although allowing achievement of the purpose, can determine negative influence on quality of wine. A promising strategy is based on the use of specific microorganisms, such as selected yeast strains, mainly non-Saccharomyces, able to convert grape must sugars towards secondary metabolites rather than ethanol. This study aims at screening of wild non-Saccharomyces strains in order to identify those suitable for the use in mixed starter for the production of wine with reduced alcohol content and, at the same time, with improved aromatic characteristics.

Highlights

In recent decades there has been an increase in the alcohol content of wine mainly linked to climate changes, which have led to the production of grapes with high sugar content and the production of wines with high level of ethanol.High alcohol content compromises wine quality [1], and represents an economic and social problem
This study aims at screening of wild non-Saccharomyces strains in order to identify those suitable for the use in mixed starter for the production of wine with reduced alcohol content and, at the same time, with improved aromatic characteristics
T. delbrueckii strains exhibited the highest resistance; two strains tolerated 200 and one strain 300 mg/L of SO2

Summary

Introduction

High alcohol content compromises wine quality (increasing hotness and bitterness perception) [1], and represents an economic and social problem. This is related both to taxes imposed in some countries for the higher alcohol drinks and to demands of modern consumers, preferring wines with a low percentage of ethanol and fruity favour. The technological approaches, proposed at this aim, include the use of strategies in vineyard (optimization of the harvest date to obtain a reduction of sugar in grape), application of pre-fermentation or winemaking practices (removal of sugar from grape must) and postfermentation practices (distillation, nanofiltration, reverse osmosis) Those techniques allow achieving this purpose, they can have a negative influence on wine’s quality of wine [3]

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Conclusion