Optimization of preparation conditions of hairtail protein polypeptide-Iron(Ⅱ) chelate by response surface methodology

The preparation conditions of hairtail protein polypeptides chelating iron(Ⅱ) were studied,with hairtail surimi as raw materials. The influences of p H,temperature,time,solution volume ratio of Fe Cl_2 to enzymatic hydrolysate and ascorbic acid content on the yield of peptide- iron( Ⅱ) chelate were investigated. The optimization experiments of response surface were designed by Box-Behnken based on above one-factor experiments. The results showed that the optimal chelating conditions were p H6.9,29 ℃,30 min,Fe Cl_2-enzymatic hydrolysate volume ratio 1∶50(V/V),and ascorbic acid content 0.1% of hydrolysate. Under these conditions,the yield of peptide-iron(Ⅱ) chelate was 80.46%. The analysis of infrared spectrum revealed that the ferrous ions were chelated with the amino groups and carboxyl groups,which suggested the formation of a new kind of peptide-iron(Ⅱ) chelate.