Stability of sunflower protein hydrolysates in simulated gastric and intestinal fluids and Caco-2 cell extracts

The in vitro stability of bioactive properties in sunflower protein hydrolysates and purified peptides was studied by using simulated gastric fluid, simulated intestinal fluid, and Caco-2 cells extracts. Protein hydrolysates that inhibit the angiotensin converting enzyme and copper chelating peptides produced by hydrolysis with the microbial protease alcalase were partially resistant to incubation with simulated gastric and intestinal fluids. These hydrolysates and others produced by hydrolysis using pepsin plus pancreatin were also partially resistant to incubation with Caco-2 cells extracts. In addition, the ACE inhibitory peptide FVNPQAGS that is generated by extensive hydrolysis using pepsin and pancreatin, was found to be resistant to hydrolysis by Caco-2 cells extracts. These results suggest that stability in the digestive tract should not be a problem for the bioavailability of these bioactive peptides.