1992 Volume 45 Issue 6 Pages 507-512
Breath hydrogen excretion was measured in 30 lactose-intolerant subject after ingesting 300ml of milk (lactose, 14g) and 500ml of yogurt (lactose, 14-16g). The mean maximum increase in breath hydrogen concentration after milk ingestion was 150 ppm (SD, 70 ppm). However it was considerably lower after ingestion of yogurt [32 ppm (SD, 33 ppm)] . Ingestion of yogurt by the subjects resulted in alleviation of abdominal symptoms such as diarrhea, abdominal pain, borborygmus and abdominal distention. A study of lactose hydrolysis using a simulated gastrointestinal digestion model showed that about 51% of lactose in yogurt was hydrolyzed after 6h incubation. In addition, it was found that microbial β-galactosidase [EC. 3. 2. 1. 23] in yogurt was finally inactivated when the gastric pH was lowered to below about 2.0, and that the enzyme was able to hydrolyze lactose in the intestine if it was not inactivated in the stomach. β-Galactosidase activity in typical yogurt prepared using Lactobacillus delbrueckii subsp. bulgaricus 2038 and Streptococcus salivarius subsp. thermophilus 1131 was 3.65U/ml, and it was not reduced markedly after the storage at 5°C for 15 days (2.74 U/ml).
