Residual proteins and α-amino nitrogen in fermented wine and beer: must variety and yeast interactions

Abstract

 A series of experimental trials as run to examine the effects both of the yeast species and the grape musts employed on the residual protein content and the α-amino N content of fermented musts and worts. The results are indicative of high levels of proteolytic activity by Hanseniaspora guilliermondii and Zygosaccharomyces veronae, which were also influenced by the grape must variety and were found in greater quantities in musts from cv. Airén grapes. The peptidolytic activity of H’spora guilliermondii and Zygosacch. veronae, either as pure cultures or in association with Saccharomyces cerevisiae, was also high and helped to sustain the level of fermentative activity of this latter species and to lower the quantity of these types of nitrogen compounds in the fermented wines and beers, thereby contributing to their physicochemical and microbiological stability.