Exploring the Potential of Bovine Whey Fermentation by Non-Selenized and Selenized Enterococcus faecium ABMC-05 for Future Functional Beverage Formulations

This study aimed to evaluate whey fermentation with Enterococcus faecium ABMC-05 to obtain a product with three functional ingredients: probiotic strains, selenium enrichment, and hydrolysates with antioxidant and antihypertensive properties. Whey, with and without sodium selenite (184 mg/mL), was fermented by Enterococcus faecium ABMC-05 and analyzed for 120 h. Free amino groups (TNBS), protein hydrolysis (Tris-Glycine-SDS-PAGE), lower molecular protein fractions (Tris-Tricine-SDS-PAGE and SEC-HPLC), antioxidant activity (DPPH and FRAP), and antihypertensive activity (ACE inhibition) were determined. The results showed that selenium accumulation in Enterococcus faecium ABMC-05 gradually increased during fermentation, reaching 2.21 µg Se/Log CFU. This was associated with a delay in the initial stage of bacterial growth and a greater release of free amino groups. Partial hydrolysis of serum β-lactoglobulin was observed by SDS-PAGE and confirmed by HPLC only in the fermentation without selenium. The levels of inhibition of the DPPH radical decreased during fermentation in both systems, while FRAP remained unchanged during the fermentation time in the selenium system. In contrast, ACE inhibitory activity increased to 53% at 120 h of fermentation in the selenium system. Therefore, the combination of the three functional ingredients may enhance bioactivity and serve as an alternative in functional dairy foods.