Preparation And Antioxodant Activity Of The Selenium-riched Rice Prptides

In order to increase the additional industrial value of the selenium-riched rice,the selenium-riched rice protein was extracted from selenium-riched rice,and the high-antioxidant activities of selenium-riched rice peptides were prepared by enzymolysis.The antioxidant abilities of selenium-riched rice peptides were evaluated and compared with rice peptides in vitro,and the functional properties of selenium-riched rice peptides were compared with selenium-riched rice protein.In addition,the antioxidant abilities of selenium-riched rice peptides,selenomethionine and rice peptides were investigated through antioxidant model in vivo.The main results were as follows:1.Preparation of Se-riched rice peptidesThe optimum extraction conditions of alkali-based selenium-riched rice protein were:0.2%NaOH as extraction solvent,material-liquid ratiol:5 g/ml,temperature 40?,the first extraction and the secondary extraction were both 1h.The purity of selenium-riched rice protein was 97.52%,extraction ratio reached 57.90%.Promamexwas selected as a optimum enzyme,DPPH·radical scavenging rate,degree of hydrolysis(DH)and selenium recovery rate were measured to evaluate hydrolysis effect.The optimum hydrolysis parameters were:selenium-riched rice protein concentration 2.5%,Promamex dosage 8000U/g,50?,pH=7.0 and hydrolysis time of 3.5h.DPPH·radical scavenging rate of selenium-riched rice peptides was 57.74%,DH was 14.7%and selenium recovery rate reached 96.12%.2.The antioxidant abilities and the functional properties of Se-riched rice peptide in vitroThe antioxidant capacities of selenium-riched rice peptides and rice peptides were compared by three kinds of tests in vitro.The results showed that they both had antioxidant activities,selenium-riched rice peptides had significantly higher antioxidant activities than rice peptides in a certain concentration range(P<0.05).It indicated that selenium in selenium-riched rice peptides had contribution to the improvement of oxidation ability.Compared with selenium-riched rice protein,the solubility,emulsifying activity,emulsifying stability and foaming capacity of selenium-riched rice peptides obviously improved,but foaming stability of selenium-riched rice protein was better than that of selenium-riched rice peptides in general.After gastrointestinal digestive enzyme digestion,DPPH·radical scavenging rate of selenium-riched rice peptides and rice peptides were lower than before,but they still retained the original activity of 75%or more in simulate digestion tests in vitro.3.Antioxidant activity of the selenium-riched rice peptides in vivoThe mice were administrated by the gavage of rice peptides(400 mg/kg.bw),selenium-riched peptides(400 mg/kg.bw),selenomethionine(2.5 ?g/kg.bw),selenium-riched peptides(200 mg/kg.bw)+selenomethionine(1.225 ?g/kg.bw)and resveratrol(10 mg/kg.bw)for 30 d respectively in different groups.It showed that compared with the model group,the effect of selenium-riched peptides was almost the best,which could significantly improve the activity of superoxide dismutase(SOD)and glutathione(GSH)level in the serum(P<0.01),significantly improve the activity of catalase(CAT)in the serum and total antioxidant capacity(T-AOC)activity in liver homogenate(P<0.05),significantly decrease malondialdehyde(MDA)level in liver homogenate(P<0.05),significantly improve GSH and glutathione peroxidase(GSH-Px)activity in liver homogenate(P<0.01)and thymus and spleen indexs showed different degrees of improvement.The antioxidant activities of selenium-riched peptides were significantly higher than that of the rice peptides and most indexes of selenium-riched peptides were also significantly better than the same selenium content of selenomethionine.It suggests that selenium and peptides in selenium-riched rice peptides have a certain synergy effect on improving antioxidant activities.