Study On Separation,Purification And Characteristics Of Antioxidative Peptides From Nuodeng Ham

Nuodeng ham is one of the specialties of Yunnan.In the process of long time fermentation,the protein was degraded by the endogenous enzyme and microbial enzyme,which produced the small molecule peptide with antioxidant activity.At present there is no research reports about the characteristics of Nuodeng ham polypeptide.In this experiment,Nuodeng ham as the object,we select the different processing time?1 years,2 years and 3 years?of the Nuodeng ham each 5,through analysis of the crude peptide extraction Nuodeng ham polypeptide characteristics,antioxidant activity and nitrite scavenging properties,and further purification and identification of antioxidant peptides,clear characteristics,specific the research contents and results are as follows:1. The phosphoric acid extraction of crude peptide processing for one or two years,three years in the Nuodeng ham.The polypeptide content were 68.35%,72%,67.20%,of which the content of polypeptide fermentation crude peptide Nuodeng ham in two years of the highest,there are significant differences with the other two years?P<0.05?.The average peptide length was 16.16?14.78 and 14.54.The average molecular weight was 2047.47Da?1872.63Da?1842.22Da,respectively,by using the method of indene ketone three colorimetric.The electrophoresi bands observed Nuodeng ham crude peptides molecular weight less than 66.2 k Da,and Processing 2 years Dengs ham crude peptide bands of the most visible electrophoretic bands of 10,3 years of processing crude peptide Nuodeng ham bands at least,and the number of electrophoresis bands clearly visible 6.2.Through the experiment on several antioxidant that Nuodeng ham crude peptide has certain antioxidant activity,With the increase of mass concentration,the antioxidant activity was enhanced.When the concentration of 5.0mg/m L,one or two,three years of processing crude peptide Nuodeng ham·OH scavenging rate reached37.31%,47.81%and 48.1%respectively.The scavenging rate of DPPH reached58.39%,67.17%and 57.76%,the Fe²⁺chelation rate reached 28.31%,31.31%and18.99%;One or two,three years Nuodeng ham crude peptide?25mg/m L?liquid on lipid oxidation inhibition rate reached 77.95%,76.79%,75.45%,The crude peptide can inhibit the Nuodeng ham protein oxidation ability.The crude peptide Nuodeng ham has sodium nitrite scavenging activity under normal conditions and gastric conditions,when the concentration was 10 mg/m L,the clearance rate reached more than 70%.3.Nuodeng ham antioxidant peptide was purified by Sephadex G-25 gel chromatography and yielded four fractions?A,B,C and D?,the in vitro antioxidant test(·OH free radical scavenging activity,DPPH radical scavenging activity and Fe²⁺chelating)that component C was the strongest antioxidant activity;Component C was separated and purified by Sephadex G-15 gel chromatography to obtain five components(C₁,C_2,C₃,C₄ and C₅).The antioxidant activity of C₃ was the strongest by in vitro antioxidant assay(·OH free radical scavenging activity,DPPH radical scavenging activity and chelating Fe²⁺),Identification of C₃ by MALDI-TOF-MS,the antioxidant activity of the peptide sequence:QVTSLSGQc HHHDEK?VHQYFNVG-LIQPGSVK?QNLLSQSHAHQQFLR?Gc FKPIVAGDQNVEYK?AIQISYNPEDL-SKPDR?NLHPELGTDADKEHWK?IRELESQISELQEDLESER?IHVSDQELQS-ANASVDDSRLEELK.