Effect of Berry Extracts on Saccharomyces cerevisiae Yeast

Abstract

Introduction. Fruit and berry extracts contain biologically active components and acids that can inhibit or activate Saccharomyces cerevisiae. The research objective was to study the effect of berry extracts on the activity of baking yeast S. cerevisiae and the biochemical properties of wheat dough.
 Study objects and methods. The experiment featured baking yeast Extra and dry berry extracts of raspberries, aronia, sea buckthorn, and rosehip (LLC Wisterra, Altai Region). The study involved standard and industry-specific control methods of raw materials and semi-finished bakery products, as well as som e standard methods of microbiological analysis. 
 Results and discussion. The raspberry extract (3–4%) suppressed the growth and reproduction of the yeast: after 1 h of exposure, the yeast cell count dropped by 1.5–2 times compared to the control sample. The stimulating effect of the sea buckthorn extract increased the growth rate of yeast cells (up to 40% compared to the control). The extracts of aronia and rosehip had practically no effect on the growth rate of yeast cells. However, 2–3% aronia extract increased the fermentation of the dough, as evidenced by a higher dough fermentation property, which was 2 min versus 3 min at the control after 150 min of exposure. Fruit and berry extracts caused a natural increase in the acidity of the dough, which affected the growth rate of yeast cells. Sea buckthorn extracts increased the acidity so much (up to 4.24 pH units) that it could be regarded as acid stress, which increased the growth rate of yeast cells (1.53×106–1.55×106 vs. 1.10×106 in 1 mL of control sample). The lowest growth rate was detected in the samples with the raspberry extract, which is known to have a strong fungistatic effect: the count of yeast cells decreased by 1.5–2 times after an hour of fermentation.
 Conclusion. Berry extracts can be of practical interest to bakery enterprises as they help to control yeast fermentation and dough maturation time.