Preparation of oyster peptide-zinc chelates

The oyster peptides were characterized according to their amino acid composition and molecular weight distribution,and the preparation conditions of the peptides-zinc chelates were analyzed. Oyster peptides and zinc sulfate were the raw materials,and chelating effect was determined by chelating ratio of zinc and the yield of the peptide-zinc chelates. The results revealed that oyster peptides were composed of 92.34%peptides with a molecular size under 1000 u,and rich in glutamic acid and glutamine,aspartic acid and asparagines. Moreover,the optimal condition of the chelating reaction was as follow:the mass ratio of peptides to Zn SO4 was 20 ∶1,the concentration of peptides was 0.06 g/m L,the reaction temperature was 50 ℃,the dosage of precipitating agent(ethanol) was 5 times as much as reaction liquid,the p H value was 5.33,and the reaction time was 60 min. Under the optimal chelating conditions,the chelated zinc ratio reached 89.55% ±0.23%,and the productive index of the peptide-zinc chelates was 56.64%±0.55%.