Isolation And Bioactivity Of Oligopeptide From Chinese Cheese

The Chinese cheese oligopeptides are some mall-molecule proteins, which are the enzymic hydrolysates of soybean protein under microbial fermentation Soybean peptides possess antioxidant, blood pressure, cholesterol-lowering and other biological activities. The purpose of the study is to determine the efficiency of oligopeptides parameter extraction and purification technology, the establishment of oligopeptides efficient extraction and purification approach. Taking Chinese cheese as the raw material, single factor experiment, multi-factor combination experiment, and response surface methods for data analysis were applied to study the water extraction, ultrafiltration fractionation, desalination with macroporous resin, and column chromatography purification of oligosaccharides peptides, at last, the purification process conditions were determined. Moreover, antioxidant and cholesterol-lowering activity tests were carried out, and the molecular weight range of peptides were determined by high performance liquid chromatography.1 Research on water extraction low molecular weight peptides. Low molecular weight peptides were extracted by water as the solvent, single-factor experiment and the second rotational regression combination design were applied to study the ratio of solid to liquid, extraction time, extraction temperature, centrifugal rotation timing on the water extraction low molecular weight peptides, the results were as following: ratio of solid to liquid 1:2.7, the extraction time 2.4h, extraction temperature 44℃, centrifugal rotation to 12200r/min. Under these conditions, the maximum extraction rate of 95.46%.2 Rating Ultrafiltration of fermented bean curd in oligopeptides. Experimental ultrafiltration membrane selected 10000 Da grading on oligopeptides experiment, test time were selected ultrafiltration, ultrafiltration pressure, feed temperature of three factors L9 (33) orthogonal test, the results were: ultrafiltration pressure 0.2 Mpa, ultrafiltration temperature 40℃, ultrafiltration time of 1.5 h. Under the optimized experimental conditions are the largest classification rate of Oligopeptides 90.5±0.5%.3 Bean curd in the desalination process of Oligopeptides and biological activity. Experimental selection D201, D301, DA201-C macroporous resin, the static adsorption experiment, the experimental results show that, DA201-C-type resin oligopeptides has a strong adsorption capacity, adsorption rate of 87%, while salt poor adsorption capacity, adsorption rate was 0.34%, therefore, experimental selection DA201-C macroporous resin, for desalination of Oligopeptides experiment. And were selected concentration of 10%, 30%, 50%, 70%, 90% ethanol elution, and tested to determine the 30% ethanol elution was oligopeptides crude has strong scavenging O2, DPPH radical scavenging ,IC50 dosage was 0.047. 70% ethanol elution was oligopeptides crude, has strong anti-lipid oxidation and cholesterol-lowering activity, IC50 dosage was 0.035 mg / mL, 0.27mg/mL.4 Purification and molecular weight determination of oligopeptides. Experimental Select SepadexG-50, SepadexG-25, SepadexG-15 three kinds of dextran on the activity of purified oligopeptide strong experimental, high performance liquid chromatography combined with the most active oligopeptides, for determine the molecular weight range, experimental results show that the molecular weight of 2180 Da ~ 3930 Da, 840 Da ~ 1850 Da, 930 Da ~ 1410 Da range of oligo-peptide, respectively, with the strongest free radical scavenging ability of lipid antioxidant system capacity and cholesterol-lowering activity.5 Oligopeptides in vitro digestion experiment. Test selection and the human body digestive, absorptive capacity similar to pepsin, trypsin, simulated gastrointestinal digestion in vitro experimental results show that the activity of trypsin on oligopeptides little effect on pepsin of the cholesterol-lowering oligopeptides activity, and made the cholesterol-lowering activity of oligopeptides declined by 11%, little effect on antioxidant activity, it can be speculated that oligopeptides in the human body has a good stability.