| Chicken blood is a by-product of chicken during the slaughtering process,which not only contains essential amino acids and beneficial components for human body such as iron and phosphorus,but also has 60%protein content,and thus has high utilization value.Hemoglobin is the most abundant protein in chicken blood,but the economic added value of domestic chicken hemoglobin products is low,so its high value utilization can be achieved by preparing bioactive peptides through enzymatic method.In this study,the enzymatic digestion process of chicken hemoglobin was optimized to obtain the enzymatic digestion products,the oxidation characteristics and structural characterization of the enzymatic digestion products were studied,the purification products were analyzed and identified,and the effect of in vitro digestion on the isolated peptides of chicken hemoglobin was investigated,aiming to provide the method and theoretical basis for the preparation and isolation and purification of chicken hemoglobin antioxidant peptides,the main research contents and results are as follows.The enzymatic digestion process of chicken hemoglobin showed that papain had the highest hydrolysis efficiency of chicken hemoglobin,with its hydrolysis degree reaching 38.4%and DPPH radical scavenging activity reaching 33.99%at 1 h.The enzymatic digestion of chicken hemoglobin was screened to obtain papain as the most suitable enzyme,and the results of single-factor experiments combined with response surface experiments,with DPPH scavenging rate as the response value,were studied to obtain the The optimum process conditions were:enzymatic digestion temperature 40℃,enzymatic digestion time 4 h,enzyme dosage 8669.45 u/g,and the enzyme dosage was optimized to 8600 u/g.The DPPH radical scavenging activity of the chicken hemoglobin hydrolysate was 67.340%,which was close to the theoretical value of 69.0685%.The antioxidant activity and characterization of chicken hemoglobin hydrolysate were investigated and found that the chicken hemoglobin hydrolysate has certain antioxidant ability,and its iron ion chelating ability,hydroxyl radical,DPPH radical scavenging activity,ABTS radical scavenging activity and reducing power were 51.791%,28.528%,67.340%,76.774%and 0.101,respectively;during the enzymatic digestion of chicken hemoglobin During the enzymatic digestion of chicken hemoglobin,the secondary structure changed,the hydrophobic amino acid content increased,and the microstructure in scanning electron microscopy changed from an umbrella-like protruding irregular distribution to a smooth spherical distribution.The separation and purification of the chicken hemoglobin peptides obtained by enzymatic digestion showed that the chicken hemoglobin peptides of the M2 component(molecular weight<3 kDa)had stronger antioxidant activity compared with the other two components(molecular weight>10 kDa(M1)and molecular weight>10 kDa(M3));then the M2 component was separated and purified by Sephadex G-25,and the results showed that the antioxidant activity of A in the M2 component was the strongest.The peptide sequence of component A was identified by LC-MS/MS and 1238 peptides were obtained.APAPAAK);the results of molecular docking with kelch-like ECH-associated protein 1(Keapl)were consistent with the results of antioxidant activity,and the peptide LSDLHAHKL had better antioxidant activity.The structural characteristics changes of chicken hemoglobin peptide during in vivo digestion and its antioxidant activity were investigated,and it was found that after gastrointestinal digestion both fractions(M1 and M2)had pores of different sizes on the surface and were irregularly reticulated,and the antioxidant activity of M2 after gastric digestion reached the strongest,and its DPPH radical scavenging rate and iron ion chelation were 33.24%and 54.27%,respectively,and The antioxidant activity of M2 with small molecular weight was always higher than that of M1. |
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