Evaluation of Autochthonous Non-Saccharomyces Yeasts by Sequential Fermentation for Wine Differentiation in Galicia (NW Spain)

Pilar Blanco,David Castrillo,María José Lorenzo,Elvira Soto,María José Graña

doi:10.3390/fermentation7030183

Pilar Blanco, David Castrillo + Show 3 more

Open Access

https://doi.org/10.3390/fermentation7030183

Copy DOI

Abstract

Non-Saccharomyces yeasts constitute a useful tool in winemaking because they secrete hydrolytic enzymes and produce metabolites that enhance wine quality; in addition, their ability to reduce alcohol content and/or to increase acidity can help to mitigate the effects of climatic change on wines. The purpose of this study was to evaluate the oenological traits of non-Saccharomyces yeast strains autochthonous from Galicia (NW Spain). To do that, we carried out sequential fermentation using 13 different species from the yeast collection of Estación de Viticultura e Enoloxía de Galicia (Evega) and Saccharomyces cerevisiae EC1118. The fermentation kinetics and yeast implantation were monitored using conventional methods and genetic techniques, respectively. The basic chemical parameters of wine were determined using the OIV official methodology, and the fermentative aroma compounds were determined by GC–FID. The results evidenced the limited fermentative power of these yeasts and the differences in their survival after the addition of S. cerevisiae to complete fermentation. Some strains reduced the alcohol and/or increased the total acidity of the wine. The positive effect on sensory wine properties as well as the production of desirable volatile compounds were confirmed for Metschnikowia spp. (Mf278 and Mp176), Lachancea thermotolerans Lt93, and Pichia kluyveri Pkl88. These strains could be used for wine diversification in Galicia.

Highlights

The fermentation of grape juice to obtain wine is a complex biochemical and microbiological process in which yeasts play an essential role
The interesting features of some nonSaccharomyces yeasts include an increase in glycerol content and total acidity, a reduction in acetic acid and ethanol content, the secretion of enzymes, and the production of secondary metabolites that enhance the wine aroma profile, or the biocontrol of spoilage microorganisms [4,8]
We studied several non-Saccharomyces yeast strains obtained from the yeast culture collection maintained at Estación de Viticultura e Enoloxía de Galicia (Evega-Agacal)

Summary

Introduction

The fermentation of grape juice to obtain wine is a complex biochemical and microbiological process in which yeasts play an essential role. Aerobic or low fermentative species (e.g., Pichia, Candida, or Hanseniaspora) and other fermentative yeasts, such as Metschnikowia, Lachancea, Torulaspora, or Zygosaccharomyces, are present in the early stages. As fermentation progresses, these species are gradually substituted by Saccharomyces cerevisiae, which has higher fermentative power and is more tolerant to ethanol [1,2,3]. In the last two decades, several studies have evidenced the positive contribution of these yeasts in improving wine quality and complexity; their role in winemaking has been reconsidered [5,6,7]. The interesting features of some nonSaccharomyces yeasts include an increase in glycerol content and total acidity, a reduction in acetic acid and ethanol content, the secretion of enzymes, and the production of secondary metabolites that enhance the wine aroma profile, or the biocontrol of spoilage microorganisms [4,8]

Objectives

Methods

Results