Study On The Preparation And Modification Of Chickpea Peptide

The advantages of chickpea protein were rich in source, low allergic, high biologicaleffect.Chickpea protein is a rare high quality plant proteins, the amino acids, protein efficacyratio and digestive rate is better than other beans. Oxidation was related to many pathogenesisof human disease such as aging, cancer, atherosclerosis, etc. Took in appropriate antioxidantactivity material can reduce the level of free radicals, prevent lipid peroxidation, helps thebody against disease, study on the chickpea antioxidant activity peptide has importantimplications，which provide the theory basis for the development and utilization of chickpearesources. In this paper the chickpea as experimental materials, study on the optimal processparameters of chickpea protein extraction, enzymatic hydrolysis chickpea protein, plasteinreaction, ultrasonic pretreatment chickpea protein, establishes enzyme dynamics model, theresults are as follows:Alkali-Solution and Acid-Sinking process have a significant influence on the extractionof protein from defatted chickpea powder. The influence order of factors to protein extractionrate is: pH> time> liquid–material ratio. The optimum conditions for the extraction ofchickpea protein to be: pH11.0, liquid–materials ratio17.7：1，time88.4min, temperature20℃. Under these conditions, protein extraction rate was up to82.33%. The regression model ofchickpea protein extraction rate was highly significant (R2=0.9630), the experimental andsimulated results were found to be in good agreement, which can be used to forecast.In the5selected enzymes: Papain, Trypsin, Pepsin, Bromelain, Alaclase, Alaclase have higher impacton enzymatic hydrolysis of chickpea protien than others. The influence order of factors to reducingpower is: enzyme content> enzyme digestion time> pH> substrate concentration；Theinfluence order of factors to·OH clearance rate is: enzyme digestion time> enzyme content>pH> substrate concentration；The influence order of factors to·OH clearance rate is: enzymedigestion time>enzyme content>pH>substrate concentration；The influence order of factors topeptide yield is: enzyme content>pH>substrate concentration>enzyme digestion time；Theinfluence order of factors to DH is: pH>enzyme digestion time>enzyme content>substrateconcentration；Consider all above,Optimization parameters of alkaline protease enzyme of chickpea peptides process are pH8.0, time90min, the amount of enzyme5000U/g, substrate concentration2%.Peptides obtained under these conditions, hydrolysis degree20.03%,·OH clearance rate76.96, reducingpower0.687, peptides yeld51.12%.Establish dynamics model of alkali protease hydrolyze chickpea protein, the resultsshowed that when pH9.0, temperature50℃, the initial substrate concentration was35g/L,the greater the initial enzyme concentration, the higher hydrolysis degree; The initial enzymeconcentration was1.75g/L, the greater the initial substrate concentration, the lowwer thehydrolysis degree,under this condition maximum reaction velocity Vmax=0.6556(g/L· min),Michaelis-Menten constant km=63.20g/L; When pH9.0, temperature50℃, hydrolyze for10min, dynamic model was DH=4.1126Log (E0/S0)+12.44, When pH9.0, temperature50℃, hydrolysis degree DH=6.024ln [1+(0.9886E0/S0+0.1632)t], constant of alkaliprotease inactivation kd=1.0428min-1.Carry on plastein reaction modification with hydrolysate from chickpea proteinhydrolysate by alkali protease, prepare highly active antioxidant peptides. With the change offree amino content indicate plastein reaction of the extent of the protein reaction, on the basisof a single factor experiment (temperature, enzyme quantity, substrate concentration),optimize the plastein reaction by the central composite design，the best conditions of plasteinreaction were: enzyme additives for500U/g, temperature30℃, substrate concentration50%,and the reaction time5.6h, Free amino decrease for175.78μmol/g，the decrease achievemaximum.The order of factors influence the plastein reaction was pH> enzyme quantity>substrate concentration. Antioxidant activity analysis results show that reduction force and OH clearance of the3products of the modified reduction force were significantly improved,the maximum of reduction force arrived at2.04, the minimum half inhibitory concentration（IC50）of OH clearance rate is7.57g/L.Ultrasonic pretreatment have influence on the reduction force,· OH clearance rate andhydrolysis degree of oxidation peptide. The influence order of factors to reduction force is:ultrasonic power> size ultrasonic temperature> ultrasonic time, The influence order offactors to· OH clearance rate、DH is: ultrasonic power> size ultrasonic temperature>ultrasonic time. The results show that the optimum conditions of ultrasonic pretreatment are750W,28min and48℃. Under the optimum conditions, hydroxyl radical、reducibility anddegree of hydrolyzing of the antioxidant peptides were95.97%,1.73and25.04%,respectively. Compared with the antioxidant peptides derived from untreated Chickpeaprotein, their half inhibitory concentration(IC50)value of hydroxyl radical decreased from10.58g/L to a8.81g/L; Reducibility increased from1.46to2.16when peptide concentrationis12g/L; Degree of hydrolysis increased from20.03%to25.04%. Over all, the ultrasonic pretreatment can improve both the enzymatic hydrolysis efficiency of Chickpea protein andantioxidant activity of it’s hydrolysates.