Optimal Combination of Soy, Buffalo, and Cow's Milk in Bioyogurt for Optimal Chemical, Nutritional, and Health Benefits.

OBJECTIVE: Soy milk is enriched with nutritive elements such as proteins, unsaturated fatty acids, lecithins, isoflavones, mineral substances, free amino acids, and polypeptides. The aim of this study was to increase the health and nutritional values of bioyogurt by using ABT-5 culture and mixing soy milk with buffalo and cow's milk.

METHODS: Five treatments of yogurt were made from soy, buffalo, and cow's milk and from 75% buffalo + 25% soy milk mixture and 75% cow + 25% soy milk mixture using ABT-5 culture.

RESULTS: Utilization of soy milk in yogurt production decreased acidity, redox potential (Eh ), total solids (TS), fat, total nitrogen, ash, total volatile fatty acids (TVFAs), saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and total amino acids contents. In contrast, the highest levels of unsaturated fatty acids (USFAs), polyunsaturated fatty acids (PUFAs), linoleic acid, and α-linolenic acid were detected. Higher numbers of L. acidophilus and bifidobacteria were found in soy milk yogurt than in buffalo or cow's milk. Blending of buffalo or cow's milk with soy milk increased the sensory evaluation scores of yogurt.

CONCLUSIONS: Mixtures of 25% soy milk + 75% buffalo milk, 25% soy milk + 75% cow's milk and ABT-5 culture could be successfully used in production of bioyogurt characterized by high health and nutritional properties. These optimal combinations highly enhanced probiotic bacteria. The recommended level of 107 cfu.g-1 of bifidobacteria as a probiotic was exceeded for soy milk yogurt treatments.