Galactose-Fermenting Yeasts as Fermentation Microorganisms in Traditional Koumiss
Graziella Montanari1, Luigi Grazia2*
1Dipartimento di Protezione e Valorizzazione Agroalimentare, Universitá di Bologna, Villa Levi-42100 Reggio Emilia, Italy
2Dipartimento di Scienze e Tecnologie Agro-Alimentari, Ambientali e Microbiologiche, Universitá del Molise, 1-86100 Campobasso, Italy
Received September 10, 1997
Accepted November 17, 1997
koumiss, yeast, Saccharomyces unisporus
Yeast flora composition was determined in 94 samples of traditional Central Asian koumiss. The dominant yeast was Saccharomyces unisporus which, though lactose non-fermenting, ferments galactose xvell and is mainly responsible for alcoholic fermentation of koumiss. Sacch. unisporus normally causes slozver and less clean alcoholic fermentation than Sacch. cerevisiae since it produces larger amounts of minor fermentation compounds such as glycerol, succinic and acetic acid. It has low alcohol producing capacity and cannot complete grape must fermentation. It is more vigorous only in milk whey where it achieves clean alcoholic fermentation.