Storage characteristics of frozen soy yogurt Prepared with different proteolytic enzymes and starter cultures

단백분해효소와 Starter Culture의 종류에 따른 frozen soy yogurt의 저장성

  • Lee Sook-Young (Department of Food and Nutrition, Chung-Ang University) ;
  • Lee Jung-Eun (Department of Food and Nutrition, Chung-Ang University)
  • 이숙영 (중앙대학교 생활과학대학 식품영양학과) ;
  • 이정은 (중앙대학교 생활과학대학 식품영양학과)
  • Published : 2005.04.01

Abstract

The storage characteristics of frozen soy yogurt prepared with hydrolyzed soy protein isolates were evaluated. In order to facilitate lactic fermentation bacteria grow and produce lactic acid as fast rate as possible, soy protein isolate(SPI) was hydrolyzed using two kinds of proteases; bromelain and a-chymotrypsin. The cultural systems employed thereafter for lactic fermentations were Bifidobacterium bifidum or B. bifidum and Lactobacillus bulgaricus. The viable cell counts, normal- and bile acid tolerances from the mixed cultures of B. bifidum and L. bulgaricus decreased sharply during the initial first 3 days of frozen storage and then showed a gradual decrease thereafter. Melt-down percent of the all frozen products have been favorably affected as was shown by less melting at raised testing temperature during 28 days of frozen storage except for the initial 3 days during which a minor change has been observed. Among the various volatile flavor components, the contents of acetaldehyde, acetone, diacetyl and methanol generally increased during the frozen storage. In sensory test, the frozen soy yogurt prepared with a-chymotrypsin and mixed culture of B. bifidum and L. bulgaricus was the most desirable, the highest scores in sourness, bitterness and mouthfeel.

Keywords

References

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