Research On The Antioxidative Activity And Preparation Of Collagen Antioxidant Peptide From Pig Skin

The development of China’s livestock industry is in a high speed, the nationaloutput of the number of the pork slaughter, meat products and byproducts have beenincreasing in value. The yield of pig skin has been more and more, but the utilizationrate of pig skin is low. The large number of collagen is in pig skin, the research on theextraction of the pig skin collagen has been relatively modest, the research on theAntioxidative Activity of the Collagen Antioxidant Peptide from Pig Skin has alsobeen deficient.This paper studies on extracting from the pig skin. The collagen was hydrolyzedin pepsin. We studied on the optimal conditions to the most antioxidant activity ofantioxidant peptide on orthogonal test. Antioxidant activity of the pigskin collagenpeptide and mode of antioxidant action were studied in the different antioxidantsystem. And the collagen peptide from pig skin was isolated and purified withsephadex, the antioxidant activity was studied for the different peptides fromseparation in the different antioxidant system. In the end, the inhibitory effect on lipidoxidation of the collagen peptide was studied in raw and cooked pork patties. Themain findings will now be summarized as follows:（1） The collagen of pig skin has been extracted. The extraction rate of collagendetermined by measuring hydroxyproline content was44.46%. To the most antioxidantactivity of antioxidant peptide, the optimal conditions were determined by the indexevaluation of the clearance rate of superoxide anions. The results showed that theenzymatic hydrolysis time was6.5h, the substrate concentration was4%, and theamount of enzyme was accounted for2.5%of substrate.（2） In order to analysis antioxidant action mode of pigskin collagen hydrolysatecomprehensively, the reduction capacity, scavenging free radical capacity, lipidoxidative capacity, metal chelating ability of pigskin collagen hydrolysate of differenthydrolysis time and concentration were studied. Pigskin collagen hydrolysates possessed marked reducing power and strong radical-scavenging ability, both of whichwere increased with hydrolysis time. The protein hydrolysates also showed strongCu²⁺-and Fe²⁺-chelation ability, and the antioxidant activity increased with substrateconcentration. The reducing power of4%pigskin collagen6h hydrolysate was similarto those of0.02%ascorbic acid.（3） The collagen peptide from pig skin was isolated and purified with a SephadexG-50column. The fraction P22peptide that was separated from the collagen peptidehad stronger antioxidant capacity, it’s stronger reducing capacity, the reducing capacityits IC₅₀was3.59mg/mL on the power to eliminate O₂^-·,4.31mg/mL on the power toeliminate HO·,3.57mg/mL on the power to eliminate DPPH,1.7mg/mL on the powerto eliminate lipid peroxidation. The molecular weight was from3.24kDa to4.32kDa.（4） The collagen antioxidant peptide at a0.5%,1.0%,1.5%,2.0%concentrationlevel were added to pork patties. During the storage period, a value, TBARS, pH valuewere measured and sensory evaluation was performed on pork patties. The resultsshowed that the treatments added collagen antioxidant peptide had significantinhibitory effects on lipid oxidation and kept the red color of patties in the storageperiod, when compared with controls. The inhibitory effect was the best at2%concentration level.0.02%BHT was added to raw patties in order to make acomparison, the conclusion was that the collagen antioxidant peptides had lowerinhibitory effects on lipid oxidation than0.02%BHT. The same results were got bysensory evaluation.