Research On Preparation And Bioactivity Of Peptides From Rapeseed Peptides

Biologically active peptides are beneficial to the life activities of biological organisms or have physiological effects.They are mainly obtained through four methods:extraction from natural substances,enzymatic protein hydrolysis,fermentation,and chemical synthesis.Studies had found that biologically active peptides have a variety of physiological functions such as antioxidant,antibacterial,and immune regulation,which has attracted widespread attention from researchers at home and abroad.As by-product of rapeseed oil production,rapeseed meal is rich in protein and balanced in amino acid composition,which is a high-quality plant protein resource.At present,the research on rapeseed protein is mainly focused on feed additives.Prediction and analysis of antimicrobial peptides from rapeseed protein using in silico approach.In this paper,rapeseed meal was selected as the raw material to prepare rapeseed peptides by enzymatic hydrolysis,and then the optimal conditions for enzymatic hydrolysis were determined by orthogonal experiments.When the solid-liquid ratio was1:10（m/m）,rapeseed protein was reacted with alkaline protease for 60 minutes,and the degree of hydrolysis was 15.96%.It could be also known that the protein content of rapeseed peptides was 47.39%,and its molecular weight was mainly distributed below2000 Da through HPLC analysis.Subsequently,the antioxidant effect of rapeseed peptides in vitro was demonstrated.When the concentration of rapeseed peptides was 1.25 mg/m L,the scavenging rate of ABTS free radicals reached 98.02%.When the concentration of rapeseed peptides reached 1 mg/m L,the scavenging rate of ABTS free radicals was98.02%.The scavenging rate of the OH×and DPPH free radicals has reached 77.21%and 87.79%,respectively.An oxidative damage experiment of HUVEC cells was also done to explore the antioxidant effect of rapeseed peptides.The results showed that when the concentration of rapeseed peptides reached 100 mg/m L and 1 mg/m L,the cell viability reached 86.84%and 93.48%,respectively,indicating that rapeseed peptides could repair the oxidative damage caused by H₂O₂ while not having toxic and side effects on normal cells.In order to verify the absorption of rapeseed peptides on the surface of human skin,a transdermal absorption experiment was carried out.It was found that the transdermal absorption coefficient of 20 mg/m L rapeseed peptides solution was 0.4308,indicating rapeseed peptides have good absorption performance ability.Then the hygroscopicity and moisture retention of rapeseed peptides were measured in two humidity environments for exploring the moisturizing effect.The results showed that rapeseed peptides had a good moisturizing effect in vitro.Subsequently,rapeseed peptides cream with stable physical and chemical properties was prepared,and the moisturizing effect was evaluated on human skin.It was found that after applying a cream with a rapeseed peptides content of 2%,in an environment which relative humidity was no more than20%,the water content can reach 36.46%,and the skin water content could still remain above 27%after 2 hours.It was suggested that rapeseed peptides have a good moisturizing effect in vitro.The anti-inflammatory effect of rapeseed peptides was evaluated in RAW264.7macrophage cell line.The results showed that when the concentration of rapeseed peptides was 1 mg/m L,the expression of interleukin 6 factor（IL-6）and tumor necrosis factor-α（TNF-α）in RAW246.7 cells induced by LPS decreased to 33.83 pg/m L and94.69 ng/m L,respectively.Subsequently,the protective effect of rapeseed peptides cream on the inflamed skin was explored through the xylene-induced ear swelling experiment in mice.It was found that when rapeseed peptides cream was added at the concentration of 3%,the swelling of the ears of the mice was reduced to 70.79%.These findings suggested that rapeseed peptides could be used as anti-inflammatory ingredient to continue in-depth research in the future.This study aimed to improve the additional economic value of rapeseed protein or rapeseed cake by exploring the physiologically active functions of rapeseed peptides.The theoretical basis will be provided for the further development of biologically active peptides which were related to cosmetic preparations and medical skin protectants.