Quantitative Changes in Sugars, Especially Oligosaccharides, During Fermentation and Storage of Yogurt

Abstract

Yogurt was prepared by fermentation with Lactobacillus bulgaricus and Streptococcus thermophilus. Lactose content (6.53%) of yogurt mix progressively decreased to 4.22% during fermentation. Initial galactose content of mix was .04% but progressively increased to 1.46% during fermentation. The initial yogurt mix did not contain detectable glucose and oligosaccharides; however, these increased during fermentation to .04 and .08%. Lactose of yogurt after 4, 6, and 10 h fermentation was 5.15, 4.76, and 4.22%, and decreased slightly during storage at 5°C for 10 days to 4.73, 4.43, and 3.89%. Galactose after 4, 6, and 10 h fermentation was .70, 1.10, and 1.46%, and increased slightly during storage to 1.05, 1.42, and 1.77%. Glucose of yogurt after 4, 6, and 10 h fermentation was .02, .02, and .04% and changed during storage to .14, .02, and .05%. Oligosaccharides after 4, 6, and 10 h fermentation were .02, .03, and .08%, and increased gradually to .20, .05, and .12%. © 1983, American Dairy Science Association. All rights reserved.