Table l-Degradation of different types of caseins by lactobacilliSince little information is available on the role of Lactobacilli in the'degradation of casein species (other than cow casein) and nonmilk protein substrates, this study was undertaken to gather information on degradative ability of lactobacilli on different protein substrates. Progressive enhancement in the liberation of tyrosine with an increase in incubation period was recorded in all the cultures. As regards the degradative ability of lactobacilli on protein substrates of nondairy origin, an increasing trend in proteolysis rate was noted up to 10 days. Results are of interest on account of faster degradation of certain protein substrates of nondairy origin by lactobacilli which contribute significantly to texture and flavor development in cultured milk-based foods.