Growth of Probiotic and Traditional Yogurt Cultures in Milk Supplemented with Whey Protein Hydrolysate

Growth of some probiotic bacteria was significantly improved in milk supplemented with whey protein hydrolysate (WPH). However, WPH had no effect on the growth of Lactobacillus delbrueckii ssp. bulgaricus 18, L. delbrueckii ssp. bulgaricus 10442, and Streptococcus thermophilus 1. When the probiotic bacteria were grown in combination with different yogurt cultures in milk, WPH caused significant increases in growth of Bifidobacterium longum S9, L. acidophilus O16, and L. acidophilus L‐1. However, by day 28 of refrigerated storage, the populations of the probiotic cultures that had been grown in samples supplemented with WPH were similar or below those in the control samples.