Extraction Of Protein From Selenium-enriched Konjac And Its Antioxidant Activity

Konjac has antioxidant effects,anti-cancer,lipid-lowering,detoxification and other health effects,and selenium is an important trace element in the human body.In order to explore the antioxidant properties of selenoproteins in konjac,this paper firstly explored the extraction method of selenium-enriched konjac protein,especially the factors affecting protein extraction rate,and determined the extraction process and optimal experimental conditions of selenium-enriched konjac protein,and the extracted protein was qualitatively and quantitatively tested;on the basis of this,the antioxidant activity of the extracted selenium-enriched konjac protein was detected from the in vitro and cellular levels.The main experimental results are as follows:?1?The optimum conditions for protein extraction were determined by alkali extraction and acid precipitation method:pH 9.0,ratio of material to liquid 1:40,extraction time 40 min and extraction temperature 40°C;the qualitative identification of selenium-enriched konjac protein by infrared spectroscopy and ultraviolet spectroscopy indicated that it was alkali-soluble protein.The protein content of selenium-enriched konjac protein was 82.05%by Folin-phenol method,the content of polysaccharide was 11.42%by anthrone-sulfuric acid method and the content of selenium was 14.90?g/g by fluorescence method,indicating that the extracted konjac protein is selenium-containing glycoprotein.At the same time,the selenium form was analyzed by high performance liquid chromatography,and the results showed that selenium in konjac protein existed in the form of selenomethionine and selenocysteine.?2?The antioxidant capacity in vitro of different concentrations of selenium-enriched konjac protein samples was investigated using different assay methods.The total reducing ability,ability to scavenge DPPH and hydroxyl radicals increased with the concentration of konjac protein in the concentration range studied;the clearance rate of DPPH is up to 58.33%,and the clearance rate of hydroxyl radicals is up to 58.46%,and the removal rate of H₂O₂ is not obvious with the increase of concentration,which is about 57%.Moreover,the antioxidant capacity of selenium-enriched konjac protein was significantly higher than that of the control albumin.?3?The protective effect of selenium-enriched konjac protein on H₂O₂-induced oxidative damage of HepG2 cells was determined by MTT assay and Hoechst33258staining.In the concentration range of 0.32-0.80 mg/mL,konjac protein samples can inhibit the oxidative damage induced by H₂O₂,indicating that the konjac protein sample has some antioxidant capacity.