Abstract

The objective of this study was to evaluate the fermentation of a soluble soy extract using lactic starters such as Lactobacillus acidophilus and Streptococcus thermophilus with L. acidophilus, Bifidobacterium spp. (SAB) and Lactobacillus casei, varying the formulations with respect to the type of carbohydrate used, such as sucrose and glucose. Twelve formulations were defined in order to verify the fermentation efficiency and possible differences in their behavior in the presence and absence of sugar supplementation. At the end of storage (28 days), the number of viable cells in the beverage fermented by L. casei varied between 10¹¹ and 10¹² viable cells/ml, demonstrating a high viability of the probiotic character. The formulations containing the SAB inoculums presented counts above 10¹¹ viable cells/mL at the end of storage. For beverages fermented using L. acidophilus, the number of lactic acid bacteria fell to a basis of 10¹¹ viable cells/ml during the 28 days of storage. As compared to the other formulations using different lactic starters, it could be seen that these showed a lower count after 28 days, but the probiotic characteristic remained viable, with significant differences between the formulations (p<0.01). Soy was shown to be an optimum medium for the development of the desired lactic cultures.

Key words: Fermentation, lactic cultures, storage, soluble soy, sugar supplementation.