Evaluation of Genetically Modified Wine Strains of Saccharomyces cerevisiae

¹ Department of Food Science and Technology, Wiegand Hall, Oregon State University, Corvallis, OR 97331-6602
² Department of Food Science and Technology, Wiegand Hall, Oregon State University, Corvallis, OR 97331-6602Center for Gene Research and Biotechnology, Ag. Sciences, Oregon State University, Corvallis, OR 97331.

Genetically modified wine strains of Saccharomyces cerevisiae were evaluated in trial fermentations to assess effects of the genetic alterations on fermentation, flavor, and aroma. Chardonnay grapes were fermented by Montrachet (UCD Enology 522), California Champagne (UCD Enology 505), Pasteur Champagne (UCD Enology 595), and corresponding inbred and heterothallic derivatives. The inbred strains had been previously derived from the parents through repeated cycles of sporulation and clonal selection and the heterothallic strains had been constructed by introducing the ho gene by hybridization into the inbred derivatives. Pasteur Champagne and its inbred and heterothallic derivatives fermented at similar rates. The inbred and heterothallic versions of Montrachet fermented at similar rates but more slowly than Montrachet. California Champagne began the fermentation earlier than either of its inbred or heterothallic forms but all three fermented at approximately the same rate. "Difference from control" tests performed by an experienced panel indicated significant differences in flavor and aroma between wines made by California Champagne and both of its derived strains and in flavor alone between wines made by the inbred derivative of Pasteur Champagne and Pasteur Champagne and its heterothallic version. No differences in flavor or aroma were detected between wines produced by Montrachet and its derivatives.

Key words: Saccharomyces cerevisiae, wine yeast, homothallism, heterothallism

Submitted on September 9, 1991