• Journal of Applied Biological Chemistry
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• v.62 no.3
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• pp.299-304
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• 2019

Yogurt was prepared with different substitution ratio [10, 20, 30, and 50% (w/w)] of skim milk with enzymatically saccharified Korean rice wine lees powder (eKRWLP) and fermented with commercially available mixed lactic acid bacteria (Bifidobacterium longum, Lactobacillus acidophilus, Streptococcus thermophilus) at $40^{\circ}C$ for 18 h. Fermentation characteristics were evaluated in terms of acid production (pH and titratable acidity) and viable cell counts of lactic acid bacteria. The pH of yogurts decreased with increasing eKRWLP substitution ratio of skim milk. After 12 h fermentation, titratable acidities of eKRWLP substitution and control (yogurt made without eKRWLP) were 0.84~1.04% and 0.93%, respectively. The titratable acidities of yogurts prepared with 10 and 20% substitution ratio increased than that of the control yogurt, but titratable acidities of yogurts of 30 and 50% substitution ratio decreased. After 9 h fermentation, the number of viable lactic acid bacterial cell were increased to 8.18~8.24 log CFU/g in all yogurts. In sensory evaluation, there were similar preference for eKRWLP yogurts prepared with 10 and 20% substitution ratio and the control. When eKRWLP substitution and control yogurts fermented for 9 h were incubated at $4^{\circ}C$, their pHs and titratable acidities were slightly changed but the number of viable lactic acid bacteria were well maintained above $10^7CFU/g$ for 11 days in yogurts prepared with 10 and 20% substitution ratio among eKRWLP substitution yogurts. These results suggest that eKRWLP can be used as substituent of skim milk and the optimum substitution ratio is around 10~20%.

• Journal of Applied Biological Chemistry
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• v.61 no.4
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• pp.315-320
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• 2018

This study was carried out to determine the effect of enzymatically saccharified Korean rice wine lees powder (eKRWLP) on the quality characteristics and storage stability of curd yogurt. Yogurt with different contents [0.5-2.0% (w/w)] of eKRWLP was incubated with commercially available mixed lactic acid bacteria (Lactobacillus acidophilus, Streptococcus thermophilus, Bifidobacterium longum) at $40^{\circ}C$ for 18 h. The production of acid measured at pH and titratable acidity of yogurts increased with increasing eKRWLP content. After 12 h fermentation, titratable acidity of eKRWLP yogurt was 0.77-0.90% and was higher than that (0.72%) of yogurt made without eKRWLP. The viable cell counts of lactic acid bacteria in eKRWLP yogurts were increased in proportion to the addition of eKRWLP, and increased up to 8.01-8.13 log CFU/g after 12 h incubation. The repressive effect of whey separation in eKRWLP yogurt curd significantly decreased than that in Korean rice wine lees powder (KRWLP) yogurt. With sensory evaluation, yogurt with 0.5% eKRWLP obtained the highest scores among all eKRWLP yogurts. When eKRWLP yogurts and the control preparations fermented for 12 h were incubated at $4^{\circ}C$, their pHs and titratable acidities were slightly changed and the number of viable lactic acid bacteria were well maintained above $10^7CFU/g$ for 16 days.