Functional properties and growth promotion of bifidobacteria and lactic acid bacteria strains by protein hydrolysates using a statistical mixture design

Soy protein isolate (SPI), bovine whey protein (BWP) and egg white protein (EWP) were hydrolyzed with the protease Flavourzyme 500L®, and the effects of the media supplemented with these different proteins and their mixtures on the growth performance of bifidobacteria and lactic acid bacteria strains and functional properties were studied using a simplex centroid mixture design. Synergistic effects between the formulations containing binary or ternary mixtures were observed for several parameters. For functional properties, the enzymatic hydrolysis increased protein solubility except for EWP and its mixtures. However the hydrolysates exhibited a tendency to decrease their foaming capacities and heat stability. A synergistic effect was found for the emulsion activity index of two binary formulations and the ternary mixture, with increases of up to 155.2%. The hydrolyzed samples positively stimulated the bacteria growth. Compared with control, the cell growth of the mix culture of Streptococcus thermophilus and Lactobacillus delbrueckii, Lactobacillus acidophilus and Bifidobacterium lactis were increased with the supplementation of the media with mixtures of BWP (1/2) plus EWP (1/2) and SPI (1/2) plus BWP (1/2) at 25.0 mg mL−1 in 100.0, 29.4 and 86.2%, respectively.