Structure characterization and bioactivities of protein hydrolysates of chia seed expeller processed with different proteases in silico and in vitro

Abstract

Chia seed (CS) expeller was hydrolyzed by 6 proteases (Alcalase, Neutrase, Protamex, Papain, Flavourzyme, Trypsin) in different hydrolytic patterns to improve bioavailability and explore the structure-enzyme active site relationship. At the meantime, in silico hydrolysis was performed to obtain a series of proteolytic sequences of chia seed protein treated by different enzymes. The hydrolysates of non-animal derived protease were further determined by in vitro experiment in terms of health-promoting activities. It is necessary to remove fiber before protease hydrolysis, and Alcalase and Flavorzyme had a good effect on the degradation of residual fiber of CS meal. Due to the diversity of enzyme cleave sites, the structure properties of hydrolysate treated by different proteases exhibited discrepancy. Furthermore, hydrolysates of CS meal presented varying bioactivity (antioxidant, hypoglycemic, hypotensive, hypolipidemic, anti-alcoholic activity). Among them, Neutrase, Protamex and Papain hydrolysis showed significant impact on the production of multiple active functional factors. The highest percentual of angiotensin I converting enzyme inhibitory (ACE) and alcohol dehydrogenase activation (ADH) effect were observed in Neutrase and Flavourzyme hydrolysates, with lowest IC50 of 0.219 ± 0.030 mg/mL and 0.047 ± 0.002 mg/mL, respectively. Ultimately, an activity-oriented protease screening method was obtained, which consists of in silico digestion and in vitro activity evaluation.