SECONDARY PRODUCTS FORMATION AS A TOOL FOR DISCRIMINATING NON-SACCHAROMYCES WINE STRAINS STRAIN DIVERSITY IN NON-SACCHAROMYCES WINE YEASTS

A total of 78 strains of non-Saccharomyces yeasts were isolated: 30 st rains of Kloeckerca apiculata, 20 of Candida stellata, 8 of Candida va lida and 20 of Zygosaccharomyces fermentati. The diversity of yeast sp ecies and strains was monitored by determining the formation of second ary products of fermentation, such as acetaldehyde, ethyl acetate and higher alcohols. Within each species, the strains were distinguishable in phenotypes through the production of different amounts of by-produ cts. In particular, a great variability was found in C. stellata, wher e six different phenotypes were identified by means of the production of acetaldehyde, ethyl acetate, isobutanol and isoamyl alcohol. At dif ferent stages of the spontaneous fermentation different phenotypes of the non-Saccharomyces yeasts were represented, characterized by consis tent differences in some by-products involved in the wine bouquet, suc h as acetaldehyde.