Screening Of Active Peptides From Quinoa And Construction And Evaluation Of Nanoemulsion

Food-derived bioactive peptides have attracted more and more attention due to their mild effect and small toxic and side effects.However,their low bioavailability hinders their application in the development of food and drug to a large extent.Quinoa protease hydrolysate(< 3k Da component)has been confirmed to have the functions of lowering blood pressure,lowering blood glucose and resisting oxidation,but the structure and molecular action mechanism of the active peptide are still unclear.Therefore,in this study,we aimed to screen peptides with antihypertensive,hypoglycemic and antioxidant activities from quinoa protein.The action targets and mechanisms of quinoa active peptides were explored by combining network pharmacology with molecular docking technology.The bioavailability of the active peptide is improved by embedding the active peptide through nano emulsification.The main research contents and results of this paper are as follows:In Chapter 1,online tool Peptide Cutter was used to conduct simulated enzymolysis on quinoa protein,and online tool Peptide Ranker,Admetsar were used to screen the active peptides and predict their biological activity,toxicity and water solubility.Taking ACE,alpha-amylase,and Keap1 protein as receptors,and screening by molecular docking to obtain an active peptide which is tightly combined with the receptor;The in vitro activity of the screened active peptides was verified.Finally,quinoa active peptide FPW with ACE inhibition,alpha-amylase inhibition and antioxidant activity was screened out,and the IC50 for ACE was 15.7 μM and the IC50 for alpha-amylase was 48.4 μM,and the peptide had good antioxidant activity.In Chapter 2,the online tool Swiss target prediction was used to predict the possible target genes of FPW,which was compared with the gene banks of hypertension,hyperglycemia and oxidation in Genecards.The protein network interaction was analyzed by STRING database and Cytoscap software,and the potential action mechanism was further explored by GO functional enrichment analysis and KEGG pathway mapping,finally the key targets were verified by molecular docking technology.The study found that among 100 potential targets of FPW,36,29 and 35 targets in hypertension,hyperglycemia and oxidation pathways were overlapped respectively.Mapping analysis of GO functional enrichment and KEGG pathway indicated that FPW might play a major role in the process of lowering blood pressure through the Ras signaling pathway.It may play a major role through the lipid and atherosclerosis signaling pathways during the hypoglycemic process.FPW may play a major role in the antioxidant process through the neutrophil extracellular trap formation-related pathway and the relaxin signaling pathway.Molecular docking results indicated that FPW was strongly associated with matrix metallopeptidase 9(MMP9),tyrosine-protein kinase SRC(SRC),matrix metallopeptidase 2(Matrix metallopeptidase 2,MMP2),Plasminogen,PLG),and peroxisome proliferatoractivated receptor gamma showed good binding affinity.In Chapter 3,the solubility of FPW in various excipients was used to preliminarily screen the oil phase,surfactant and cosurfactant of nanoemulsion.The oil phase,surfactant,cosurfactant and the ratio of surfactant to cosurfactant(Km)of nanoemulsion were determined by plotting the pseudo-ternary phase diagram and comparing its area.The formulation was optimized by central composite design and response surface methodology with particle size and embedding rate as indexes.The nanoemulsion was prepared with the optimal formula,and characterized for its stability.The experiment proved that when the ratio of oleic acid in nano-emulsion phase was14.96%,the ratio of active agent PEG40 was 18.91%,and the ratio of cosurfactant propylene glycol was 18.91%,the maximum embedding rate of 77% and the minimum particle size of 16.7 nm could be achieved.The turbidity of the nanoemulsion was 23.52,the p H was 7.02,and the potential was-20.51.The appearance,particle size and embedding rate of nanoemulsion were almost unchanged under the dilution,alkaline and refrigerated environments.In the acidic and frozen environment,stratification occurred,the particle size became larger,and the embedding rate decreased.In addition,the storage stability of the nanoemulsion was good,and the properties were almost unchanged after 35 days of storage at room temperature.