Soybean peptides' cryoprotective effects on Saccharomyces cerevisiae fermenting power in frozen dough and maintenance of the Chinese steamed bread qualities

Strain leavening power loss and product quality deterioration are the two main issues in frozen dough technology being used during Chinese steamed bread manufacture. Our study added soybean peptides (SP) in the Saccharomyces cerevisiae growth medium to restore its fermentative capability in dough and maintain the steamed bread qualities. When dough was not frozen, 0.1% (w/v) SP-added group's fermenting rate was 4.6 times of the control with no SP. When dough was frozen at −20°C for 7 and 30 days prior to fermentation, respectively, fermenting speed of 0.1% SP group was 4.8 and 8 times of the control group. Bread from dough of the SP group also had better qualities. Adding 0.1% SP into medium also increased cells' extracellular enzyme activity to 50 times of the blank. This study demonstrates the possibility of using edible SP to maintain strain fermenting power and bread qualities for frozen dough technology. Practical applications Chinese steamed bread is a widely consumed cereal product in East Asia, whose fermenting Saccharomyces cerevisiae has various claimed benefits to product quality. Keeping this yeast's fermenting power at low temperatures could be a challenge to industries when frozen dough technology is applied. Soybean peptides have been proved to promote fermenting microorganisms' growth at low temperatures in other food products. This study provided some evidences on how soybean peptides reserved the S. cerevisiae fermenting power during the dough freezing time frame while maintained the product organoleptic qualities; therefore, soybean peptides could have a potential application for Chinese steamed bread industries.