Determination of the oenological properties of yeast strains isolated from spontaneously fermented grape musts obtained from cool climate grape varieties

Paweł Satora,Monika Cioch-Skoneczny,Szymon Skoneczny,Aneta Pater

doi:10.1007/s00217-020-03574-0

Paweł Satora, Monika Cioch-Skoneczny + Show 2 more

Open Access

https://doi.org/10.1007/s00217-020-03574-0

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Abstract

The international competitiveness of the wine sector and consumer demands for the unique wine styles pose challenges in improving the fermentation process. The basis of proper alcoholic fermentation is knowledge about how individual yeast strains interact with the aroma, taste and color of wine, what results in possibility to select species used as starter cultures. To use the value of non-Saccharomyces yeast strains in wine production and to minimize the possibility of wine deterioration, it is necessary to precisely recognize the yeast cultures present on the fruit of the vine and in grape must, as well as their metabolic properties. The aim of the study was to determine the oenological properties of yeasts isolated from spontaneously fermented grape musts obtained from cool climate grapes. For this purpose, Zweigelt grape must was fermented with yeast monocultures. Alcohol, extract, sugars, glycerol, total acidity and free amine nitrogen were analyzed in the obtained wines. Poor fermentation properties of yeast strains results in obtaining wines with relatively large amounts of residual sugars and low alcohol. A decrease in overall acidity was noted in sets with the participation of M. pulcherrima MG971264, while in other tests the opposite trend was observed. Although some microorganisms have the ability to assimilate organic acids found in wine, they are not able to carry out fermentation or they do it inefficiently. Solution to this problem may, therefore, be use of mixed cultures of noble and non-Saccharomyces yeast, what effectively reduce the concentration of organic acids, while not adversely affecting the organoleptic characteristics of the drink.

Highlights

One of the most important technological achievements in winemaking was inoculation of grape juice with noble cultures of Saccharomyces cerevisiae, what made it possible to control the fermentation process [1,2,3]
The presence of non-Saccharomyces yeast during the wine fermentation process, it carries a risk of spoilage, is generally considered as desirable [12, 20, 21]
Cultures not belonging to the genus Saccharomyces, including H. uvarum (MG971252, MG971254, MG971255, MG971266) were characterized by weaker fermentation kinetics, which is confirmed by literature data [33]

Summary

Introduction

One of the most important technological achievements in winemaking was inoculation of grape juice with noble cultures of Saccharomyces cerevisiae, what made it possible to control the fermentation process [1,2,3]. One of many products of metabolism of these microbes, plays a role in regulating the oxidoreductive potential of cells [22, 23]. It gives wines a feeling of smoothness and taste complexity [24]. Fermented grape musts have glycerol in higher concentration [11, 25], what is the result of the presence of native grape yeast. Similar to C. stellata, increased amount of acetic acid are the result of the presence of these microorganisms in grape must [26]. Microorganisms characterized by high production of these compounds include Pichia anomala and K. apiculata strains [27]

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