Dual function peptides from pepsin hydrolysates of whey protein isolate

The aim of this study was to investigate the effect of pepsin hydrolysates of whey protein isolate (WPI) on vascular relaxation and emulsifying capacity. WPI was subjected to pepsin hydrolysis for 5 h. The chromatographic profiles of the samples showed the formation of a wide variety of peptides. Addition of WPI hydrolysates in phenylephrine-contracted rat aortic rings induced a similar concentration-dependent relaxation in both endothelium-intact and endothelium-denuded preparations. In endothelium-denuded vessels the maximum relaxation induced by WPI fractions increased along the time, reaching over 70% after 3 h-hydrolysis on. In addition, the vascular relaxation was not associated with an inhibition of the angiotensin-converting enzyme or activation of K+ channels. Hydrolysed fractions were further evaluated for the emulsifying capacity (EC) and all tested fractions were able to keep an EC over 60%. These results reinforce the potential of WPI pepsin-hydrolysates as an option in the search for dual function peptides from whey proteins.