Casein Antioxidant Peptides Were Separated And Structure-activity Discussion

This paper mainly studies the antioxidant free radical scavenging effect of the casein hydrolyzate and various peptides casein hydrolyzate in vivo. Pepsin, papain and rennet casein hydrolyzate were used to make antioxidant activity peptides. With hydroxyl radical clearance rate as an indicator and the degree of hydrolysis as a reference,a better antioxidant hydrolyzate protease was screened out through the hydrolysates experiment of antioxidant activity in vitro, and the optimized reaction conditions of casein hydrolysis were obtained through orthogonal experiments. Under optimum reaction conditions, through the way of centrifugation, ultrafiltration,etc,hydrolyzate was divided into different molecular weight hydrolyzate peptide,and then the antioxidant effects of molecular weight in different concentrations were studied. Finally by animal experiments, glutathione peroxidase (GSH-PX) activity, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in mouse liver were measured, and the effects of Antioxidant peptides in different molecular weight in vivo were obtained. Experimental results show that:Papain hydrolyzate has the lowest clearance rate; pepsin has a higher removal effect in120min; the hydroxyl radical scavenging rate of rennet casein hydrolyzate increases with time, the upward trend reaches the maximum at90min. with the clotting enzyme as Single factor, hydroxyl radical scavenging rate as an indicator and the degree of hydrolysis as a reference, experimental results show that when the temperature is45℃pH6.5, the hydrolysis time of90min, enzyme adding amount ofl:10, hydroxyl radical scavenging rate reaches the maximum. Respectively23.51%,55.89%,75.68%,45.29. Orthogonal experiment results show that when the temperature is50℃, pH7.0, hydrolysis time of60min, enzyme adding amount of3%, the rate of hydroxyl free removal reaches the maximum.Then, under optimum conditions, according to peptide molecular weight,the hydrolyzate was divided into three groups,greater than3ku, lk-3ku and less than lku to study peptide concentration and molecular weight size on the rate of free radical scavenging. When the concentration is8mg/mL,-OH clearance rates were64.07%,65.87%,73.33%;when the concentration is lOmg/mL, DPPH-clearance rates were80.16%,89.89%,90.94%.Through animal experiments of the target detection of Kunming mice antioxidant enzymes (GSH-PX, SOD, MDA), the effects of different molecular weight on the organisms were understood. Casein peptides enable mouse liver tissue glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) activity increased, and malondialdehyde (MDA) content decreased.