The Influence of Enological Practices on the Selection of Wild Yeast Strains in Spontaneons Fermentation Spontaneons Fermentation

摘要

The aim of this work is to establish the influence of some enological treatments: grape juice clarification (by settling and by vacuum filtering), fermentation temperature (14 deg C and 18 deg C) and nitrogen addition (DAP 30 g/ hL and commercial activator 15.5 g/hL), on the natural selection of wild Saccharomyces cerevisiae strains during the spontaneous fermentation of white grape juice, of the Viura variety from La Rioja (Spain). Mitochondrial DNA analysis is applied to the study of 240 isolates from two consecutive harvests. The results reveal one new effect of the clarification treatment: the selection effect on the wild yeast strain of Saccharomyces cerevisiae in spontaneous fermentation. However, the strain distribution is independent of fermentation temperature and nitrogen addition.