Study On Separation And Antioxidant Function Of Protein Peptides And Polysaccharides From EBN

Edible Bird's Nest is a kind of famous and expensive invigorant,which has a long history for food in China and South-East Asia areas.Nest pieces are piece-materials produced during the process of transportation and production.The nutrition of nest-pieces is just the same as Yan-beacon and Yan-strips,however,these pieces had hardly been made full use of,because of their shapes and containing too much feather or impurities.The skills combined with bio-enzymolysis and barrier separation has been used to separate and purify the peptides and polysaccharides and to evaluate their antioxidant function.The main results are as follows:Based on the standard of degrees of hydrolysis,water soluble protein and polysaccharides,I have made experiments on the conditions of enzymolysis proteins in the nest-pieces through the analysis of single-element and corresponding elements and improve the conditions.The results of the experiments have proved that neutral proteinase can make it well to hydrolyze protein in EBN.The hydrolysis conditions are pH 7.0;dosage of enzymes 4500 U/g;time of enzymolysis:24 hours;enzymolysis 60?.The nest pieces are melt in the enzymolysis liquid for 24 hours,then condense the liquid and after drying,protein has been obtained.The content of protein in the sample is 79.54%.The peptides in EBN have better extracorporeal antioxidant function.The maximum thickness to clean DPPH free radicals,superoxide anionic free radicals?O₂^-·?,hydroxyl radicals?·OH?reach as 2mg/mL?20 mg/mL?35 mg/mL,and the cleaning rates reach as 27.25±0.09%?58.04±2.25%?52.10±1.09%.The protein peptides in the nest-pieces have obvious protecting function for liver cells to anti-H₂O₂.Compared with the H₂O₂ dealt-group,the protein peptides in the nest-pieces can decrease content of MDA cells by 32.90%,and increase SOD enzyme activity by 25.60%,both of which have reached very famous levels.Using gelatum Sephadex G-25,We can get five groups,afterwards we can find the main peptides are WGDVADDSS?VLKTLK?SGSPAQL?HPLGD?NNPY?LPSTH?GAQLE?TGFFFF?NPHY?GVYLL.The liquid left by ultrafiltration was enzymolysed again by 10 kDa films,the remaining liquid has been enzymolysed by 30 kDa.The last period,we can get nest-polysaccharides by means of condensing,alcohol precipitation and drying.The amounts of it in the products is 33.10±0.19%.After purifying of column-chromatography of the protein peptides in the nest-pieces,and using gelatum Sephadex G-100,nest-polysaccharides could be got.Its main components are glycoprteins,with the average molecular weight 49 kDA.Tested with HPLC,six monosaccharide compnents as Man?GlcN?GalN?Gal?Xyl?Fuc can be found,among which the content of Gal is highest.The maximum thickness to clean DPPH free radicals,superoxide anionic free radicals?O₂^-·?,hydroxyl radicals?·OH?reach as 1 mg/mL?30 mg/mL?25 mg/mL,and the cleaning rates reach as 37.52±0.22%?36.65±0.03%?30.10±0.77%.In the thickness of 10?g/mL,the protein peptides in the nest-pieces have obvious protecting function for liver cells to anti-H₂O₂.Compared with the H₂O₂ dealt-group,the polysaccharide in the nest-pieces can decrease content of MDA cells by23.10%,and increase SOD enzyme activity by 47.60%.And both of them have reached famous levels.