| Chickpea(Cicer arietinum L.)is the third largest legume in the world,second only to soybean and pea.It is also a common medicinal material in Uighur medicine.Chickpea peptides have attracted extensive attention because of their antioxidant,immunomodulatory and hypolipidemic activities.Taking germinated chickpea protein as the research object,the germinated chickpea protein was hydrolyzed by enzymatic hydrolysis,the enzymatic hydrolysis parameters were optimized by response surface methodology,the chemical antioxidant capacity of germinated chickpea protein and its hydrolysate and its effect on the hemolysis inhibition of erythrocytes induced by AAPH were studied by in vitro gastrointestinal digestion experiment,and the chickpea protease hydrolysate was isolated,purified and identified,Finally,chickpea polypeptide Seabuckthorn compound beverage was prepared by compounding the prepared polypeptide with concentrated seabuckthorn juice.The main results are as follows:(1)Preparation of antioxidant peptides from germinated chickpea by hydrolysis with five proteases(neutrase,alcalase).The enzymatic hydrolysis process was optimized by response surface methodology with the yield of peptides and DPPH radical scavenging activity as the indexes.The results showed that the peptide yield and DPPH radical scavenging rate of alcalase hydrolysate were the highest;Design expert 10.0.7software was used to determine that the optimum process condition for hydrolysis was substrate concentration 1%,enzyme dosage 12000 U/g,enzymatic hydrolysis temperature 60℃,enzymatic hydrolysis p H 10.0 and enzymatic hydrolysis time 1.5 h.at this time,the yield of polypeptide was 55.07±3.44%and the DPPH radical scavenging rate was 43.71±2.09%.(2)The chemical antioxidant capacity of CP and HCP and their effects on the hemolysis inhibition of erythrocytes induced by AAPH were studied by gastrointestinal digestion in vitro.The results showed that gastrointestinal digestion had different effects on CP and HCP.Among them,CP is more easily digested by the stomach.After gastrointestinal digestion,the hydroxyl radical antioxidant activity of GI digest of HCP was the strongest,and the DPPH radical scavenging ability of gastric digest of CP was the strongest.However,the GI digestion products of both have good antioxidant activity.In the hemolysis test of erythrocytes induced by AAPH,the GI digests of CP and HCP can protect erythrocytes from hemoglobin oxidation induced by AAPH,and slow down the production of MDA and the depletion of GSH in erythrocytes within a certain period of time.(3)Sephadex gel and LC-MS/MS were used to isolate,purify and identify HCP,and synthesize them to verify their antioxidant activities.The results showed that the chickpea polypeptide was separated by Sephadex G-75 to obtain three components(HCP-1,HCP-2 and HCP-3).The DPPH,hydroxyl and ABTS~+free radical scavenging ability of component HCP-3 was the highest.Five peptide sequences of component HCP-3 were identified by mass spectrometry.Among them,the peptide sequences AGDTHLGGEDFDNR and SDALDKIRFE were found to be new peptides by BIOPEP database.The antioxidant activities of the synthetic peptides were compared and analyzed.It was found that the DPPH and hydroxyl radical scavenging abilities of the two peptides were higher than those of the purified peptides at the same concentration.(4)Taking germinated chickpea polypeptide and seabuckthorn as raw materials,according to the amount of additives in chickpea polypeptide Seabuckthorn composite beverage,the beverage formula with the best taste was prepared and its antioxidant capacity was evaluated.The results showed that the preparation conditions and parameters of germinated chickpea polypeptide Seabuckthorn composite beverage were as follows:sugar addition 9.0%,polypeptide addition 25.0%,seabuckthorn concentrated juice addition 2.0%,citric acid addition 0.35%.The clearance rates of DPPH and hydroxyl radical were 95.31%and 94.53%respectively. |
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