Support of growth and formation of d-amino acids by Bifidobacterium longum in cows', ewes', goats' milk and modified whey powder products

The growth of Bifidobacterium longum was studied in skimmed cows', ewes' and goats' milk, in mixtures of cows' and ewes' milk and goats' skimmed milk and whey powder products from these two types of milk. d-Aspartic and d-glutamic acids were also studied as markers of the protein of microbial origin. In the first 8-12 h of a 24-h fermentation period, the development of acidity was faster and the population was higher in goats' and ewes' milk than in cows' milk. Some stimulatory effects were also found with whey powder products from ewes' and goats' milk. The values of d-aspartic and d-glutamic acids increased during the fermentation period and there was significant correlation with the microbial population.