Abstract

The objective of this paper was to assess the fermentation diversity of twoSaccharomyces cerevisiae strains and one Saccharomyces bayanus var. uvarumoriginated from fruit juice or pulp and previously classified as the ones with extended demalication ability. The fermentation profiles of yeast were assessed after 20 sequential subcultures (50 to 160 generations) under aerobic or semi-anaerobic conditions in media with or without L-malic acid. During this study, 15 apple wines produced by wild strains and their segregates were statistically evaluated according to 13 chemical parameters. The studied yeasts revealed pronounced polymorphism of fermentation profiles. The ability of yeasts to decompose L-malic acid, differentiates the wild strains and their segregates, which suggests a possible role of this acid in the process of evolutionary diversification of yeasts. Although yeasts isolated from natural plant environments may be successfully used in acidic musts fermentation, their instability probably caused by adaptive changes should be taken into account. The presented results indicate that the assessment of fermentative stability under environmental stress can help in the evaluation of yeast selected for the fermentation of specific musts.

Key words: Wine yeasts, Saccharomyces cerevisiae, Saccharomyces bayanus var.uvarum, stability, acidic musts