Research On Antioxidant Activity Of Black-bone Silky Fowl Peptides And Purification Of Antioxidant Peptides

Many chronic diseases and human aging phenomenon have something to do with the imbalance of free radicals inside human body. External antioxidants can help people to maintain the balance of free radicals inside body. It's possible to develop effective antioxidant drugs and health foods on the base of the research, screening and modification of natural foods with antioxidant activity. Black-bone silky fowl has special nutritional invigoration and medicinal value. It's also a good source of protein.In this paper, the detection methods of antioxidant activity of black-bone silky fowl peptides, the enzymatic hydrolysis conditions of black-bone silky fowl protein, and the purification of peptides with hydroxyl radicals scavenging activity of black-bone silky fowl peptides were investigated.1. Detection methods of vitro antioxidant activity of black-bone silky fowl peptides were established. On the basis of the analysis of black-bone silky fowl protein hydrolysate ingredients, antioxidant capacity of black-bone silky fowl protein hydrolysate were detected, including scavenging activity of super oxide anion, hydroxyl radicals, and DPPH free radicals, reductive ability and ability to prevent lipid peroxidation. Experimental results showed that black-bone silky fowl protein hydrolysate showed some antioxidant activity in different detection systems. Scavenging activity of hydroxyl radicals was the highest. It showed good prospects in development.2. Further enzymatic hydrolysis technics of black-bone silky fowl protein was determined. After single enzyme hydrolysis experiment as hydroxyl radical scavenging for target, the best enzyme was trypsin. After L16(45) orthogonal test, the optimum conditions of trypsin digestion were temperature 50℃, initial pH8.5, 6000U/g of E/S, 6h of enzymatic hydrolysis time, 9% of substrate concentration. Peptides from this technics showed 45.4% of hydroxyl radicals scavenging activity (33.3μg/mL of peptide concentration), which was 4% higher than Vc on the same concentration.3. Antioxidant peptides were purified as hydroxyl radical scavenging ability for target. The best Sephadex G-25 gel chromatography separation conditions of black-bone silky fowl peptides were determined: eluted with deionized water, 1 mL/min elution speed, 50mg/mL of sample concentration, and 0.30mL sample. Black-bone silky fowl peptides could be separated into five peaks, among which the fourth peak(D) had the highest hydroxyl radical scavenging activity, and its IC50 was 34.3μg/mL. The best ion exchange chromatography separation conditions of peak D were determined: using Fractogel EMD TMAE column, 1mL sample, using linear gradient elution of pH9.5 buffer. D peaks were divided into three peaks on this condiction, among which peak D3 had the highest hydroxyl radical scavenging ability, and its IC50 was 13.1μg/mL, which was 3.95 times of its initial hydroxyl radical scavenging activity, 4.67 times of Vc's hydroxyl radical scavenging activity. HPLC analysis showed that the peak D3 was not a single matter, which had at least three components. Amino acid analysis showed that the peak D3 was mainly consisted by Tyr, Leu, Lys, Ala and Arg.