| In the study,the Decapterus maruadsi was hydrolyzed by trypsin,papain and Alcalase protease,respectively.The mineral ions(Ca2+,Fe2+,Zn2+)chelating activity of the hydrolysates was studied.At the same time,the antioxidant stability of the hydrolysates was studied,which provided reference for the development and utilization of the functional products.The hydrolysates were separated by immobilized ion affinity chromatography.The amino acid analysis and molecular weight distribution were performed to determine the antioxidant activity of the mineral chelating peptides.1.The Decapterus maruadsi was hydrolyzed by trypsin,papain and Alcalase protease,respectively.The mineral ions(Ca2+,Fe2+,Zn2+)chelating activity of the hydrolysates was studied.The results showed that the hydrolysates obtained from Decapterus maruadsi hydrolyzed by trypsin(DH=23.14%)had the highest chelating activity with Fe2+ and Zn2+.The chelating rates were 96.63% and 94.28%,respectively.The Decapterus maruadsi protein hydrolyzed by papain(DH=22.0%)has the highest chelating activity with Ca2+,and the chelating rate was 96.78%.The results also showed that those two enzymatic hydrolysates had good antioxidant activity.The IC50 values for DPPH free radical scavenging activity of the hydrolysateswere 3.74 mg/mL and 3.64 mg/mL,respectively.In addition,the amino acid analysisshowed that the hydrolysates with a high content of Glu,Asp,Lys had high mineral ion chelating activity.2 Tricine-SDS-PAGE small peptide electrophoresis analysis showed that with the extension of the enzymolysis time,the macromolecular protein in the hydrolysate was gradually reduced,and the small molecular protein or peptide increased.3.DPPH scavenging ability and reducing power of trypsin hydrolysates and papain hydrolysates with Decapterus maruadsi as index,the effects of temperature,pH,metal ions and food additives,gastrointestinal digestion of two kinds of enzymatic antioxidant stability was studied.The results showed that the two kinds of enzymatic hydrolysates had good thermal stability in a certain range,and the antioxidant stability was better in acidic environment.The concentration of NaCl and xylose in the experimental concentration had little effect on the antioxidant stability of the hydrolysates,glucose,fructose and citric acid could enhance the antioxidant activity of the two enzymes.In this experiment,the 5 kinds of metal ions have some influence on the enzymatic hydrolysates,and the influence of metal ions on the enzymatic hydrolysis products is analyzed: Cu2+>Zn2+>Ca2+>K+>Mg2+.Artificial gastrointestinal digestion experiments,decapterusmaruadsi hydrolysate decreased antioxidant activity of gastric digestion of protein,followed by simulated intestinal digestion,improve the antioxidant capacity of the product,and maintain a certain antioxidant activity.The results confirm the significance of the addition of peptides in diet.4.The Decapterusmaruadsi hydrolysateswere separated by ultrafiltration method.Comparing the antioxidant activity of three components,molecular weight less than 5 kDa,the molecular weight of more than 5 kDa less than 10 kDa,the molecular weight of more than 10 kDa.The results showed that the molecular weight of less than 10 kDa components have a stronger antioxidant activity.Respectively using immobilized calcium ions,zinc ions,ferrous ion affinity chromatography(Ca2+,Zn2+,Fe2+-IMAC)separated the two kinds of enzyme solution,three kinds of IMAC column elution conditions were determined,the IC50 of DPPH scavenging capacity of calcium chelating peptides,zinc chelating peptides and ferrous chelating peptides were 0.127,0.063 and 0.106 mg/mL.And the target product distribution analysis,amino acid content and molecular weight analysis results show that the compound has mineral binding peptides content of aspartic acid and glutamic acid activity than the original hydrolysate percentage increased Decapterusmaruadsi enzyme,while small molecule peptide has higher metal chelating activity. |
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