Preparation and function of oligopeptide-enriched hydrolysate from globin by pepsin

Animal blood is potentially an untapped source of drugs and value-added food production. More than 400 million pigs are slaughtered each year but porcine blood is usually discarded in China. In this paper, globin derived from porcine hemoglobin was digested by pepsin, then the hydrolysate was separated on Sephadex LH-20 gel filtration column and five major fractions (I, II, III, IV and V) were obtained. Biological functions of the hydrolysate and five fractions were assayed. The hydrolysate and fractions IV and V had good angiotensin-I-converting enzyme inhibitory activity, with IC50 values of 1.19, 0.67, 0.10 mg/ml, respectively. Fractions I, II, III, IV showed no significant α-glucosidase inhibitory activity, but fraction V showed appreciably stronger activity than acarbose at the same concentration. Thus, the study has shown that porcine blood can be utilized to generate high value-added products, ACE inhibitory peptides and α-glucosidase inhibitory peptides.