Preparation Of ACE Inhibitor Peptide From Yuchaza Bean By Ultrasonic-assisted Enzymatic Method And Its Antioxidant Activity

Cyperus esculentus was an emerging economic crop with high comprehensive utilization value and great development potential,containing 8%?10%protein.In recent years,the extraction of ACE inhibitory peptides by enzymatic hydrolysis of plant-derived proteins has become a research hotspot.In this experiment,the ACE inhibitory peptide were extracted and purified from Cyperus esculentus as raw materials and their antioxidant effect were studied.The following conclusions were obtained:(1)Using Cyperus esculentus as raw material,the protein is extracted by alkali-dissolving acid precipitation method.Select alkaline protease to hydrolyze Cyperus esculentus protein to extract Cyperus esculentus ACE inhibitory peptide.Under the same experimental conditions,the ACE inhibition rate and degree of hydrolysis are used as indicators,the ultrasonic coenzyme method and ordinary enzymolysis method were used to compare the extraction of ACE inhibitory peptides from Cyperus esculentus.The results showed that the ACE inhibition rate of the ultrasonic coenzyme method was 74.45%,and the degree of hydrolysis was 16.15%:The ACE inhibition rate of ordinary enzymatic hydrolysis is 65.89%,and the degree of hydrolysis was 10.28%,Therefore,the experiment used the ultrasonic coenzyme method to extract the ACE inhibitory peptides of the Cyperus esculentus.Through the response surface method to optimize test,the best extraction process conditions were obtained as:The substrate concentration was 3%,the ultrasonic power was 183 W,the ultrasonic time was 20 min,the amount of enzyme added was 5000 U/g,the enzymatic hydrolysis temperature was 45?,and the enzymatic hydrolysis time was 3h,and the ACE inhibition rate was 74.35%.Three verification tests were carried out under this condition,and the ACE inhibition rate of Cyperus esculentus was 74.45%,There was a good fit between the predicted value and the true value.Therefore,in this study,the response surface method was used to optimize the ultrasonic coenzyme method to extract the ACE inhibitory peptide from Cyperus esculentus.(2)The macroporous adsorption resin and dextran gel were used to separate and purify the ACE inhibitory peptides of Cyperus esculentus.Used DA201-C macroporous resin to preliminarily purify the Cyperus esculentus ACE inhibitor peptide,and then further purify it on a G-15 dextran gel column to collect the eluate.Three absorption peaks Z_?,Z_?and Z_?are detected by UV spectrophotometer,Determine each component with ACE inhibition rate as an indicator,results Z_?was61.87%,Z_?was 78.85%,Z_?was 67.59%.The inhibition rate of the Cyperus esculentus ACE inhibitor peptide(Z)was 83.09%.(3)Compared the Cyperus esculentus ACE inhibitory peptide with the control group V_C under the same conditions to test and evaluate its antioxidant capacity.Used DPPH free radical scavenging rate,superoxide anion free radical scavenging rate,hydroxyl free radical scavenging rate and reducing ability as indicators to detect the anti-oxidation ability of the Cyperus esculentus ACE inhibitory peptide and each component.The clearance rate of the purified Cyperus esculentus ACE inhibitor peptide(Z)is significantly higher than the other three components.When the peptide concentration was 10 mg/m L,the maximum DPPH free radical scavenging rate was88.92%;when the peptide concentration was 15 mg/m L,the maximum superoxide anion free radical scavenging rate was 49.78%;when the peptide concentration was20 mg/m L,the hydroxyl group was free the maximum base clearance rate was28.96%;the maximum reduction ability was 2.903 when the peptide concentration was 25 mg/m L.Higher V_C reduction ability than the positive control group.