The effect of prolonged freezing on the content of thiol substances and proteolytic activity of yeast

DOI: 10.17586/1606-4313-2018-17-3-62-66
UDC 577/ 663.126

The effect of prolonged freezing on the content of thiol substances and proteolytic activity of yeast

Skvortcova N.N., Shleykin A.G., Arykbayeva A. B.

For citation: Skvortsova N.N., Shleikin A.G., Arykbayeva A.B. The effect of prolonged freezing on the content of thiol substances and proteolytic activity of yeast. Vestnik Mezhdunarodnoi akademii kholoda. 2018. No 3. p. 62-66

Abstract
The article deals with the changes of sulfhydryl group content, reduced glutathione content, and proteolytic activity in dried and pressed baker yeast of Saccharomyces cerevisiae species stored at the temperature of –20±2 °С. The objects of the study were the commercial samples of Saccharomyces cerevisiae: Saf-Moment dried yeast and compressed yeast manufactured by Russian Saf-Neva and Combine foods companies, respectively. The yeast samples were stored in a freezer at –20 °C for 35 days. Aliquots were taken at 5, 10, 15, 20, 25, and 35 days, and the total amount of reduced thiol compounds, reduced glutathione content, and proteolytic activity were determined. The results of the study demonstrated that for 35 days of storage the total content of thiol substances increased: in dried yeast by 8.3%, in pressed yeast 2.5-fold; the content of reduced glutathione increased in dry yeast by 37.3%, and in pressed yeast 7-fold. Under the same conditions the proteolytic activity decreased: in dried yeast 3.2-fold, in pressed yeast – 8.6-fold.

Keywords: yeast, freezing, reduced glutathione, proteolytic activity.


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