| Selenium is one of the essential trace elements in the human body,and proper selenium supplementation has a positive effect on human health.Inorganic selenium supplements such as sodium selenite are common selenium supplements at present,but their bioavailability is low,toxic and side effects are large,and the limitation of application is obvious.Therefore,transforming inorganic selenium into organic selenium through biological transformation is an effective way to develop selenium supplements.Based on the previous research of the research group,this research used sodium selenite as the selenium source to enrich and transform selenium with soybean to obtain selenium-rich soybean protein,and then used protease to digest the selenium-rich soybean protein.Selenium-enriched Soybean Peptide(SSP)was prepared and the composition and structure of SSP were preliminarily characterized.The acute toxicity and anti-oxidant capacity of SSP were evaluated.The main research results and conclusions of this study are as follows:1.Optimum desalting conditions of selenium-enriched soybean proteolysis solution: When the sample had a p H of 3,a temperature of 25°C,a resin-to-sample volume ratio of 0.2,an adsorption time of 2 hours,and an elution solvent of 50% ethanol,the yield of SSP was 73.78% and the desalination rate was 94.51% after desalination.In addition,SSP with a total selenium content of 40.75 mg/kg can be obtained.2.Various characterization methods showed that SSP was mainly acidic amino acids,and the molecular weight was mainly between 612Da-1422Da;besides,the secondary structure of SSP was complete with mainly ?-helix.Compared with selenium-enriched soybean protein,SSP had a more concentrated pyrolysis temperature.3.The results of acute oral toxicity test of SSP in mice showed that intragastric administration of SSP at 10.0g/kg · BW within 24 hours wouldn't cause acute death of the mice nor would it affect the appetite and weight gain of the mice,but would reduce liver coefficient.The selenium content in the feces of mice could return to normal levels on the third day after administration.The selenium absorbed into the body was mainly distributed in liver and kidney.Female mice had higher selenium's level than male mice.4.The IC50 value of SSP to remove DPPH was 1.39 mg/m L and the IC50 value of SSP to remove hydroxyl radicals was 0.54 mg/m L which was closer to ascorbic acid.The ferrous reducing ability of SSP was 0.678 mmol/g.The results of cellular experiments showed that the IC50 value of SSP on Hep G2 was between 20mg/m L and 25mg/m L.Intervening cells with SSP below 20mg/m L could increase the survival rate of Hep G2,improve the cell growth status and prevent the oxidative damage of Hep G2.5.Prophylactic administration of SSP could increase the levels of TAOC,CAT and GSH-Px in the liver of oxidatively injured rats,but not decrease significantly the levels of NO and TNF-?.The blood lipids were not significantly different from the model group.Pathological sections of the liver tissue showed that the liver lobules of the rats in the SSP group could still be distinguished,and the liver cells containing lipid droplets did not exceed 3/4.In summary,DA201-C macroporous adsorption resin is effective for desalting SSP,lower in cost and easier to operate,which are beneficial to the preliminary separation and purification of SSP.SSP is basically nontoxic and it can show a good ability to scavenge hydroxyl radicals,which is not much different from the strong antioxidant substance such as ascorbic acid.SSP can also prevent the oxidative damage to Hep G2 cells by improving cell viability and affecting CAT activity.In addition,SSP can reduce damage to liver caused by HFD through increasing the level of antioxidant enzymes in liver.The above shows that SSP has certain antioxidant capacity in vivo and in vitro. |
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