Study On The Preparation And Structural Characteristics Of Whey Protein Peptide Iron Chelation

In China,iron deficiency anemia is one of the main nutritional deficiency,and the traditional iron supplement slow absorption and gastrointestinal stimulation restrict its application.Therefore,the new type of iron supplement,which is safe and nutritious,is widely concerned.A new type of iron filling agent is a biological iron complex,which is mainly divided into amino acid iron chelation and polypeptide iron chelation.At present,the amino acid and polypeptide metal chelation have been studied at home and abroad,but the iron chelation of whey protein as raw materials are still relatively lack.In this project,whey protein was used as raw material to prepare iron chelating peptides by enzymatic hydrolysis.The obtained peptides were combined with iron to prepare whey protein peptide-iron chelation,and the technological conditions were optimized to study the structure of the chelation of iron peptides.The functional properties provide a theoretical basis for the research and application of new peptide organic iron supplements.Firstly,the whey protein hydrolyzing conditions were optimized.Pepsin and trypsin were selected to prepare iron chelation peptides.The degree of hydrolysis and iron chelation rate were used as indicators.The results showed that the whey protein peptides obtained by trypsin hydrolysis were higher of hydrolysis degree and iron chelation rate.Then optimize trypsin hydrolysis reaction conditions（enzyme dosage,time）,the results showed that the best enzymolysis process:the amount of enzyme 1.5 KU/g protein,time 4.0 h hydrolysis and iron chelation rate reached the maximum,respectively,16.10%and 34.10%.Secondly,optimize the preparation conditions of whey protein peptide-iron chelation,and use iron chelation rate and chelation yield index to influence the chelation reaction factors:ferric peptide mass ratio,substrate concentration,temperature,time.The molecular weight of the polypeptide was optimized.The results showed that the substrate concentration ion was 40mg/mL（mass ratio was 1:3）,and the iron chelation rate and chelation yield reached the maximum at 35℃for 30 min,which were 77.38%and 80.05%,respectively.And found that<3 KDa whey protein peptide,iron chelation rate and chelation yield were significantly higher than other peptides,respectively 85.92%,77.70%.The calculated yield of whey protein peptide-iron chelation from whey protein was 12.40%.Finally,using FT-IR analysis of the whey protein peptide-iron chelation chemical bond method,it was shown that Fe²⁺formed a coordination bond with-NH and-C=O in the whey protein peptide,forming a stable chelation of the ring structure.>10 KDa and<3 KDa peptides differ in the amino acid composition of leucine（Leu）and valine（Val）content,suggesting that the branched structure of leucine and valine can promote the peptides iron chelation.Together,thereby increasing the rate of iron chelation.In vitro simulation of gastrointestinal tract results showed that chelation were resistant to gastrointestinal digestion.Oxford cup double plate experiment and DPPH free radical scavenging rate measurement results showed that the iron peptide chelation had good antibacterial and antioxidant properties.