Porcine Hemoglobin Hydrolysate Prepared with Pepsin: Antioxidant Activities and Their Mechanisms

Abstract

Different antioxidant assays were employed in order to evaluate antioxidant activities of porcine hemoglobin hydrolysate (PHH) prepared with pepsin and compared with natural and synthetic antioxidants. Molecular weight distributions of PHH polypeptide components were determined. PHH exhibited DPPH/superoxide/hydroxyl radicals scavenging (EC₅₀ 0.95 ± 0.01 mg/ml, 20.34 ± 2.83 mg/ml, 7.90 ± 0.58 mg/ml, respectively); reducing power (EC₅₀ 3.02 ± 0.91 mg/ml); and metal chelating activity (EC₅₀ 2.59 ± 0.05 mg/ml) in a dose-dependent manner. Hydroxyl radicals scavenging activity of PHH was equivalent to ascorbic acid. Relatively less active of PHH exhibited strong synergistic antioxidant activity with α-tocopherol (TOH). Tested combinations (2:1 and 1:1 of PHH:TOH) showed significantly higher antioxidant activities (P < 0.05) compared to combinations with low PHH rates (1:2 and 1:4 of PHH:TOH). The main synergistic antioxidant mechanism could be due to the regeneration of TOH by PHH. Radicals scavenging mechanism, more than metal chelation, could play a major role in the antioxidant process of PHH.

Keywords:

• Enzymatic hydrolysis
• Porcine hemoglobin hydrolysate
• Pepsin
• Antioxidant activity
• Free radical scavenging activity

ACKNOWLEDGMENTS

This work was supported financially by the National Science Technology Minister of China (award number: 2006BAD05A16) and Department of Science and Technology of Zhejiang Province of China (award number: 2006C12082).