Effects of Different Contents of Yogurt Starter/Probiotic Bacteria, Storage Time and Different Concentration of Cysteine on the Microflora Characteristics of Bio-Yogurt

摘要

The objectives of this study, were to investigate the effects of different content of yogurt starter/probiotic bacteria, storage time and different concentration of cysteine on the microflora characteristics of bio-yogurt. The number of S. thermophilus and L. delbrueckii subsp. Bulgaricus were found to be higher in the samples with higher levels of starter. The numbers of L. acidophilus and B. bifidum were found to be higher in the samples with higher levels of added probiotic bacteria. The counts of S. thermophilus increased slowly during storage up to day 7 and decreased later L. delbrueckii subsp. Bulgaricus, B. bifidum and L. acidophilus counts, decreased during the storage period. Increasing of cysteine improved the viability of B. bifidum and L. delbrueckii subsp. Bulgaricus and it had no important effect on the viability of L. acidophilus and made the environment unfavourable for the growth of S. thermophilus.