Study On Enzymatic Hydrolysis Of Pea Protein And Antioxidant Activity Of Enzymatic Hydrolysates

The protease was used to hydrolyze pea protein,and pea protein was used as the raw material to study the enzymatic hydrolysis process of pea protein.Increase the deep processing and resource utilization of pea protein powder,a by-product of pea starch processing.The separation and purification of the hydrolysates and the analysis of their antioxidant properties provided a theoretical basis for the further development and utilization of pea proteins and enzyme hydrolysates,The reference data or theoretical reference is provided for the extraction of protein peptides.Using the degree of pea protease hydrolysis as an indicator,five types of proteases(alkaline protease,neutral protease,papain,trypsin,and complex protease)were studied by single factor hydrolysis.The research results show that the conditions of alkaline protease hydrolysis to obtain a high degree of hydrolysis enzymatic hydrolysis were: substrate concentration 5%;p H 8.0;enzymatic bottom ratio 6%;hydrolysis temperature 55 ℃,hydrolysis time 3 h,and the degree of hydrolysis20.80%;The conditions for neutral protease hydrolysis were: substrate concentration5%;p H 7.0;enzyme bottom ratio 8%;hydrolysis temperature 50 ℃;hydrolysis time3.5 h,and the degree of hydrolysis 15.54%;The conditions for papain enzymatic hydrolysis were: substrate concentration 2.5%;p H 7.0;enzyme bottom ratio 5%;hydrolysis temperature 65 ℃;hydrolysis time 2 h,and the degree of hydrolysis9.46%;The conditions for trypsin enzymatic hydrolysis were: substrate concentration2.5%;p H 11.0;enzyme bottom ratio 10%;hydrolysis temperature 52 ℃;hydrolysis time 3.5 h,and the degree of hydrolysis 16.90%;The conditions of complex protease hydrolysis were: substrate concentration 5%;p H 7.0;enzyme bottom ratio 6%;hydrolysis temperature 50 ° C;hydrolysis time 3 h,and the degree of hydrolysis20.27%.Using the degree of enzyme hydrolysis as an index,the response-surface method was used to optimize the hydrolysis-assisted alkaline protease and complex protease hydrolysis processes.The results show that the optimal conditions for ultrasonicassisted alkaline protease hydrolysis of pea protein were p H 8.0,ultrasonic power420.67 W,ultrasonic time 20.51 min,ultrasonic temperature 56.62 ℃,and enzyme bottom ratio 6.0%.Under this condition,the degree of hydrolysis of pea protein was34.32%.The optimum process conditions for ultrasonic-assisted complex protease to hydrolyze pea protein were p H 7.00,ultrasonic power 417.84 W,ultrasonic time 20.8min,ultrasonic temperature 51.2 ℃,enzyme bottom ratio 6.5% Under these conditions,the degree of hydrolysis of pea protein was 36.30%.The DPPH radical scavenging rate of the enzymatic hydrolysate obtained under the optimal conditions was analyzed.The DPPH radical scavenging rate of the alkaline proteolysate was24.76%;the DPPH radical scavenging rate of the complex proteolytic product was35.48%.Two methods were used to separate the enzymatic hydrolysate of pea protein hydrolysed by ultrasonic-assisted complex protease,and the antioxidative properties of the enzymatic hydrolysate and the separated components were compared and analyzed.After gel chromatography,the enzymatic hydrolysate was clearly divided into 3main peaks,of which the elution time of the F1 separation peak was 58 min,the elution time of the F2 separation peak was 90 min,and the elution time of the F3 separation peak For 110 min.After calculation,the molecular weight of the F1 separation peak is 10444.80 Da,the molecular weight of the F2 separation peak is445.96 Da,and the molecular weight of the F3 separation peak is 62.13 Da.Among them,the F2 peak has the strongest oxidation resistance,and the scavenging rates of hydroxyl radical,superoxide superoxide anion and DPPH radical reach 21.42%,62.24% and 54.57% respectively.And then use the dialysis bag to dialyze out three kinds of enzymatic hydrolysates with different molecular weights,which are molecular weight<1000 Da,molecular weight between 1000-3000 Da and molecular weight>3000 Da.Enzyme hydrolysates <1000 Da have the strongest antioxidant capacity,and the scavenging rates of hydroxyl radicals,superoxide superoxide anions,and DPPH radicals reached22.39%,61.38%,and 55.42%,respectively.After two separation experiments,it was proved that the molecular weight of the hydrolysate-assisted complex protease hydrolysate is less than 1000 Da,and it has good oxidation resistance.