Manufacturing of iron binding peptide using sericin hydrolysate and its bioavailability in iron deficient rat

Silk sericin protein was hydrolyzed by seven proteolytic enzymes to examine the effectiveness of the hydrolysates to bind iron. The amino acid nitrogen contents of hydrolysates by Flavourzyme were higher than the others enzymes, and its iron binding capacity showed dose-dependent increase. The bioavailability of iron binding peptide from sericin hydolysates was investigated in iron-deficient rats. Three-week-old male rats were fed iron-deficient diet for three weeks. Rats were divided into four groups (DD: no treated group on iron deficient diet, DD+HI: heme-iron treated group, DD+OI: sericin-Fe, and DD+II: inorganic iron (FeSO4) treated group, and then iron supplemented by injection for one week. After oral administration for one week, the iron contents of serum and liver were significantly higher in DD+OI (4.2 μg/mL and 80.1 μg/mL) and DD+HI (3.2 μg/mL and 70.6 μg/mL) than DD (2.0 μg/mL and 47.9 μg/mL). Hemoglobin content of treated groups was significantly higher than DD, but the significant difference among groups was not shown. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels did not show any significant difference among all groups. Binding iron to peptide from sericin hydolysates seems to improve its bioavailability and to hasten the cure of iron deficiency in experimental rat.