Physicochemical Properties of Dioscorea opposita Thunb. Solution Fermented by Lactobacillus bulgaricus

The present study was designed to determine the physicochemical properties of yam (Dioscorea) solution fermented by L. bulgaricus, the protective effect of fermented Dioscorea opposita Thunb. on stomach lesions, and the possibility of its application to fermented dairy products. When the concentration of yam increased, the pH increased in raw powder samples but not in extracted powder samples. In 6% raw powder containing the sample, the viable cell counts showed a dramatic increase, whereas those in extracted yam powder significantly decreased in all concentrations during 32 h of fermentation. The viscosity of extracted yam powder showed a lower value than that of raw powder, which was maintained throughout the fermentation. The solution of Dioscorea opposita Thunb. raw powder showed a significantly higher allantoin content compared with the extracted powder (p