USE OF MILK WHEY FOR YEAST ACTIVATION IN BEER PRODUCTION TECHNOLOGY

doi: 10.25712/ASTU.2072-8921.2021.02.016

Abstract

The research is devoted to studying the possibility of using milk whey to activate brewer's yeast cultures and assessing their influence on the wort fermentation process and the quality of the finished beer. The object of the study is dry bottom-fermented brewer's yeast Saccharomyces cerevisiae of the Saflager W-34/70 strain and dry cheese whey. Prefermentative treatment of dry yeast consists of its rehydration by dilution in beer wort (1 : 10) at 5 ± 1 ºС for 30 minutes and subsequent activation with whey at different ratios of yeast + beer wort : whey – 1 : 0.5 and 1 : 1 with an exposure time of two hours. It is found that the optimal parameters for stimulating the vital activity of Saflager W-34/70 brewer's yeast at the stage of inoculum preparation (after rehydration) is their activation with whey at yeast + beer wort : whey – 1 : 0.5 with exposure for 60 minutes at temperature 5 ± 1 ºC. It is shown that the use of milk whey for pre-fermentation treatment of yeast with these parameters leads to an increase in their zymase activity by 2.7 times, and α-glucosidase activity by 1.8 times compared to the control. In addition, an improvement in the physiological state of yeast and an increase in the biosynthetic processes in cells is observed, which is reflected in a 1.8-fold decrease in the number of non-viable cells and an increase in the number of budding and glycogen-containing cells by 1.6 and 1.7 times, respectively, compared to the control. The expediency of using yeast inoculum activated with whey to intensify the fermentation of beer wort is shown; it allows reducing the duration of the main fermentation by 1.5 days, increasing the degree of fermentation of the extract, as well as getting ready-made beer with a lower level of fermentation by-products, such as diacetyl and acetaldehyde.