Studies On Key Techniques And Its Characteristics Of Egg Albumin Enzymolysis

In this study,protein powder was used as raw material to study the key technology of egg white protein controllable enzymatic hydrolysis.The chromatographic technique and functional evaluation method were used to explore the characteristics of egg white source active peptide,in order to provide theoretical basis for the development of egg functional products.Firstly,based on the alkaline protease enzymatic hydrolysis of egg albumin,the quaternary quadratic regression orthogonal rotation combination design was used to optimize the enzymatic hydrolysis process,that is,when the hydrolysis temperature was 57.1?,the substrate concentration was 3%,and the enzyme dosage was 4906.1 u/g.When the hydrolysis time was 264.3 min,it was the optimum condition for egg white protease hydrolysis,and the degree of hydrolysis reached 17.12±0.41%.Then,the alkaline protease was analyzed to digest the kinetic mechanism of egg albumin and the kinetic equation of controlled enzymatic hydrolysis was established.Overall,the theoretical value of the degree of hydrolysis is compared with the actual value,and the model fit is better.Secondly,the egg white protein hydrolysate was separated and fractionated by the 10 KD and 3KD ultrafiltration membranes to obtain the egg white antioxidant peptides of three different ultrafiltration components.The results showed that the antioxidant activities of different ultrafiltration components were different.Among them,the component EWPH-III had the strongest antioxidant activity(P<0.05).The two components obtained by separation and purification of EWPH-III by ion exchange chromatography,wherein the DPPH radical scavenging rate of the acidic component A was 79.86%,and the DPPH radical scavenging rate of the alkaline component B was 82.05%.Among the four components obtained by gel filtration chromatography separation of EWPH-III-B,the DPPH radical scavenging rates of the four components C,D,E and F were 83.63%,85.26%,88.49%and 87.62%,respectively,of which EWPH The-III-BE component has the strongest antioxidant activity.Finally,the mass fingerprint and amino acid sequence of the antioxidant peptide were analyzed by MALDI-TOF-TOF-MS mass spectrometry.The amino acid sequence was Ala-Met.Next,the effects of temperature,pH,food ingredients,metal ions,preservatives and other factors on the stability of EWPH-III antioxidant activity were studied.The results showed that commonly used food ingredients such as sucrose,glucose,salt,citric acid and preservatives had little effect on the antioxidant activity of egg white peptides,and their activity retention rates were all above 90%.When the pH value was 10,the activity was The retention rate dropped to 63%.Metal ions such as Zn2+and Cu2+have the most obvious influence on the retention rate of egg white peptide antioxidant activity.In addition,the gastrointestinal digestion process was simulated to investigate the antioxidant activity of egg white peptide before and after digestion.The scavenging ability of the product after digestion was 86.32%(increased by 7.7%),the reducing power was 1.29(increased by 0.39),and superoxide The anion free radical scavenging capacity was 77.21%(increased by 13.85%),indicating that the egg white peptide produced some more antioxidant active peptides through the gastrointestinal enzyme system.