摘要
Casein is rich in bioactive peptides,but most of them are inactive in native casein.Microbial fermentation has been considered as an effective method to release bioactive peptides using their powerful and strain-specific proteolysis system.In this paper,the structural characteristics and antioxidant activities of casein hydrolysates(CNHs)fermented by Lactiplantibacillus plantarum A56 and A157 were investigated.Both 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)(ABTS^(+))and hydroxyl radical results showed that CNHs demonstrated significantly enhanced radical scavenging ability compared to native casein,where the IC50 of ABTS^(+)and hydroxyl radical scavenging ability was 0.65 mg/mL(24h)and 2.97 mg/mL(24h)for A157 and 1.34 mg/mL(24h)and 3.33 mg/mL(24h)for A56.Furthermore,the native casein was hydrolyzed into small molecular peptides,15 or 16 kinds of free amino acid were identified in CNHs(7 for native casein),and the hydrolysis raised theα-helix andβ-turn rate,but reducedβ-sheet and random roil rate.In addition,cellular antioxidant experiments indicated that CNHs protected RAW264.7 cells against lipopolysaccharide(LPS)-induced oxidative damage,increased cell viability,elevated cellular superoxide dismutase(SOD)levels,decreased cellular reactive oxygen species(ROS)levels and inhibited mitochondrial membrane potential(MMP)decline.By searching and comparing the bioactive peptide databases,a variety of bioactive peptides with various bioactivities were found in the CNHs,such as antioxidant activity and immunomodulatory activity.These results suggested that the CNHs were with excellent antioxidant activity and contained many bioactive peptides and provided an effective way to produce bioactive peptides.
基金
financially supported by the Basic Research Project of Free Exploration,Science and Technology Department of Jilin Province(YDZJ202201ZYTS688).
