Preparation process optimization and evaluation of bioactive peptides from Carya cathayensis Sarg meal

Carya cathayensis Sarg meal (CM) is a by-product of the edible kernel during oil manufacture. In order to improve wastes utilization, the CM derived peptides (CMPs) that showed an in vitro radical scavenging ability were firstly prepared by five different hydrolases. Alcalase treatment revealed the highest yield and the optimal conditions were further determined by response surface methodology (RSM), under which the yield reached 35.84%. Simulated gastrointestinal digestion led to an enrichment of low molecular weight (MW) peptides (<3 kDa), which was beneficial for protecting hepatocyte damaged by hydrogen peroxide (H₂O₂). Furthermore, generated hydrolysates exhibited protective effects on paraquat-induced Caenorhabditis elegans via enhancing expressions of Skinhead-1 (SKN-1) and its downstream target including glutathione S-transferase (GST)-4 and superoxide dismutase (SOD)-3 to diminish oxidative stress. Taken together, our results demonstrated that simple enzymatic hydrolysis of crude protein powder from CM represents an efficient, eco-friendly and economical strategy for producing bioactive peptides, which can be supplemented in nutraceutical products and food preservation.