Study On Se-enriched Tenebrio Molitor Protein And Bioactivity Of Its Se-containing Peptides

Selenium(Se)is a necessary trace element for human.Lack of Se will lead to body's antioxidant capacity and immune function decreased.Selenium supplement can improve body immunity and avoid various diseases.Previous studies about Se-enrichemnt by plants and microorganisms shown that selenium present in organism mainly in organic selenium form.However,studies about selenium enrichment in animal remains rare.Therefore,the present study using enriched mealworm as ingredient,obtaining bioactive selenium-containing peptides(Se-TMP)by Enzymatic hydrolysis.Aiming to fill the gap in basic field research,exploring new selenium resources in the application field.Considering the effects of T.molitor lipids on further experiment,the lipids was extracted and further purified for physical and chemical properties study.Results show the lipids extraction rate was 61.53%.Dehumidification,degumming,deacidification and decolorization can greatly improve the quality of lipids.The lipid contains 32 types of fatty acids,30.34% linoleic acid and 1.24% linolenic acid.How Se-enrichment affect mealworm protein composition were discussed.Results show the totoal selenium content is 573.32 ?g/kg,and 90% is in oganic selenium form.In soluble fraction,selenium was mainly present in alkali-soluble protein.In the soluble and insoluble components of Tenebrio molitor,the distribution trend of selenium content and protein content were consistent,were residue > alkali-soluble protein > soluble protein > salt-soluble protein > gliadin.Compared to TM,the protein content of Se-TM was increased,and molecular weight corresponding to 75 ku and 37 ku protein electrophoresis band deepened.The antioxidant activities of Se-TMP and TMP were determined based on DPPH free radical and hydroxly radical scavenging rate,and erythrocyte hemolysis model.Results showed the inhibition rate on hemolysis of Se-TMP was significantly higher than TMP at same concentration.Under 3 mg/mL,the inhibition rates of erythrocytes hemolysis were 88.32% and 86.10%,respectively(control group at 92.89%).Se-TMP had better ability to scavenge DPPH and ·OH free radicals than TMP within certain concentration.Se-TM were hydrolysised by alkaline protease,trypsin and flavor protease,obtaining Se-TMP-J,Se-TMP-Y,Se-TMP-F.Immune activity were tested on macrophages RAW 264.7.NO,TNF-? and IL-6 level by macrophages were determined.The hydrostate with highest immune activity was purified for isolation.Results showed: the immune activity and selenium content were consistent: Se-TMP-J> Se-TMP-Y > Se-TMP-F,and selenium content were 1064.90 ?g/kg,917.7 ?g/kg and 0.8017 ?g/kg respectively.Se-TMP-J was purified by anion exchange chromatography.Four fractions J1,J2,J3 and J4 were obtained,and J4 had the highest immune activity.The concentration of NO,TNF-? and IL-6 treated with 31.25 ?g/mL J4 increased 13.53 ?mol/mL,12.29 ng/mL and 13.15 ng/mL respectively.J4 were further purified using gel column chromatography,J4-1 and J4-2 were obtained.The levels of NO,TNF-? and IL-6 treated with 31.25 ?g/mL J4-1 were increased by 15.20 ?mol/mL,12.82 ng/mL and 14.85 ng/mL more than control groups respectively,and increased 6.67 ?mol/mL,8.96 ng/mL and 11.26 ng/mL compared to the non-purified Se-TMP respectively.