Influence of co-cultures of Streptococcus thermophilus and probiotic lactobacilli on quality and antioxidant capacity parameters of lactose-free fermented dairy beverages containing Syzygium cumini (L.) Skeels pulp.

This study investigated the influence of probiotic lactobacilli in co-culture with Streptococcus thermophilus on composition, physicochemical parameters, microbial viability, sensory acceptability, antioxidant capacity and protein profile of lactose-free fermented dairy beverages with added whey, ß-galactosidase and jambolan (Syzygium cumini (L.) Skeels) pulp. Three beverages (T1, T2 and T3) were prepared with Streptococcus thermophilus TA-40 as starter culture. Lactobacillus rhamnosus LR32 and Lactobacillus casei BGP93 probiotic cultures were added into T2 and T3, respectively. The probiotic adjuvants slightly influenced the pH and titratable acidity of dairy beverages, with no influence on the proximate composition and on the sensory attributes. Samples presented fat and protein contents suitable to meet the requirements of "low-fat dairy beverages with non-dairy ingredients added" according to the Brazilian legislation, lactobacilli viability above 7 log CFU g-1 for both probiotics and total phenolic content around 40 mg GAE 100 g-1. Colour was the most evaluated sensory aspect (average scores close or higher than 8 in a scale from 0 to 10 for most of the sampling periods). The overall antioxidant capacity increased significantly following the addition of jambolan (p < 0.05), and significantly more during storage (p < 0.05), likely due to proteolysis verified in the electrophoresis gels, as a result of the metabolism of the lactic cultures. The dairy beverages studied are good options for functional foods due to their nutritional value, viability of probiotic lactobacilli, phenolic content, and antioxidant capacity, also serving lactose-intolerant people.

Influence of a Co-culture of Streptococcus thermophilus and Lactobacillus casei on the Proteolysis and ACE-Inhibitory Activity of a Beverage Based on Reconstituted Goat Whey Powder.

The potential for reusability of whey is of concern due to its substantial nutritional value and, second, in view of the need to reduce environmental impact. The use of goat whey powder in the production of a fermented dairy beverage using a Lactobacillus casei culture as adjunct shows a good prospect of a food product with hypotensive activity. This study investigated the microbial viability, proteolysis and angiotensin-converting enzyme (ACE) inhibitory activity of a fermented dairy beverage produced with goat whey powder and a probiotic culture of L. casei BGP93 co-cultured with Streptococcus thermophilus TA-40. The probiotic beverage exhibited no significant difference from the control (absence of L. casei) with regard to titratable acidity, S. thermophilus viability and proteolysis degree during 21 days of storage (P > 0.05). During this period, the beverage maintained L. casei at appropriate levels (> 7 log cfu ml-1), thereby qualifying as a potential probiotic product. Although both control and probiotic beverages exhibited ACE inhibitory activity, as a result of proteolysis of whey proteins during fermentation, significant increased ACE inhibitory activity was found for the beverage with added probiotic L. casei (P < 0.05). The probiotic beverage has potency as a functional food candidate to be included in a dietary strategy aiming at prevention and control of hypertension.