Study On The Preparation And Properties Research Of Wheat Protein Hydrolysate Rich In Glutamine

Wheat gluten is a kind of rich nutrition and food safety vegetable protein,it is a by-product wheat starch production of rich source and low price.Due to its refractory faults, the application is limited severely, successful preparation of wheat protein hydrolysate rich in glutamine,not only it overcomes the drawback of wheat gluten protein difficult soluble,but also solves the weakness of instability.Besides,making it applied more widely in the field of food,feed and so on.In this paper,using wheat gluten protein as raw material,preparation the wheat protein hydrolysate rich in glutamine by double enzymatic hydrolysis,exploring and study the characteristics of physical-chemical properties and biological function of the enzymolysis products.The main experimental contents and results were as follows:(1) Using optimizing the wheat gluten protein as raw material,selecting the better protease is alkaline protease through four kinds of proteinase on wheat gluten protein.The results from wheat gluten protein by single factor experiments indicated that the optimal conditions were as follows:the substrate concentration 4%,pH8.5,temperature 60℃,enzyme concentration 2%,extraction time 2h.Under the condition of the preparation of wheat protein hydrolysate,the degree of hydrolysis was 21.38%,the protein extraction rate can reach 44.23%,glutamine content is 30.1%.The alkaline protease compound with other protease, through the screening of enzyme solution combination, to find a better combination of alkaline protease and compound protease enzyme solution,wheat gluten protein to make use of this two enzymes compound enzyme,protein extraction rate increased significantly,and through the Box-Behnken central composite design(CCD) and response surface analysis(RSM) to establish the dynamics of wheat gluten protein compound enzyme of quadratic multinomial model:Y=-42.4318+61.9082A+25.1833B+35.0451C-13.2633A2-2.4900AB-18.8733B2-1.7200AC-1.0900BC-7.2468C2,with the model testing results,it has a good application value.Wheat gluten protease solution of the optimization process conditions were as follows:compound protease enzymolysis time 2h,alkaline protease enzymolysis time 0.5h,compound protease and basic protein ratio is 1:2(W/W).The preparation of wheat protein hydrolysate under the optimal condition,the protein extraction rate can up to 47.81% and glutamine content is 31.2%.(2) Analysing the physical and chemical properties of wheat protein hydrolysate,the results showed that wheat protein hydrolysate of trichloroacetic acid nitrogen solubility index(TCA-NSI) is 83.42%,the average length of peptide chain is 4.97,HPLC analysis of wheat protein hydrolysate relative molecular weight distribution of each molecule segment has appeared,the majority of which is less than 3000 Da,accounted for more than half of the total peptides,explaining through double step enzymolysis that wheat gluten protein molecular weight is greatly reduced,by amino acid analysis wheat protein hydrolysate in the composition of free amino acid and hydrolytic amino acid,free amino acid is relatively few,but the composition is very rich,contains 18 kinds of amino acids,which contains essential amino acids,amino acid composition is more balanced,proline and leucine content is higher,the highest content of glutamic acid and reached one-third of the total amount of its content in hydrolytic amino acid, by scanning electron microscopy(SEM) of wheat gluten and wheat protein hydrolysate made comparative analysis of the microstructure of surface with digestion after its surface structure has obviously changed,analysis through the Fourier infrared spectrum,hydrolysis of wheat protein peptide significantly shortened,the characteristics of functional groups,the peak by the amide group is the most significant,proved the hydrolysis of wheat protein rich in Gln.(3) The molecular weight of 3000 u ultrafiltration membranes were used for wheat gluten,conduct preliminary protease solution separation,choosing the best operation parameters were as follows:pressure is 0.10 MPa,material liquid concentration is 2.0%~2.5%,the temperature of 35℃.By using ultrafiltration method of ion exchange resin desalination of Yin and Yang group peptide purification,compared before and after enzymolysis purification material content,amino acid and glutamine,the change of the molecular mass,DPPH free radicals clearance,Fe3+ reducing power,hydroxyl radical scavenging capacity and antioxidant indexes such as super oxygen anion removal ability.The results show that small molecular weight content of glutamine slightly higher and a significant antioxidant activity,has great application value.(4) Using DSS induced mice establish the colitis model,after the completion of colitis model to give nutrient solution of hydrolyzed wheat protein rich in glutamine,mice will be put to death after continuous irrigation seven day.Observation of colitis colonic mucosa pathological tissue changes,by the detection of colon tissue super oxide dismutase(SOD),reduced glutathione(GSH),malondialdehyde(MDA) and so on of activity,using the fluorescent quantitative PCR determination of inflammatory cells in the colon tissue factor expression.The results showed that wheat protein hydrolysate nutrient solution reduced the colonic mucosa pathological damage,colitis colon antioxidant levels and myeloperoxidase activity increases.Rich in glutamine wheat protein hydrolysate nutrient solution plays a part in mice colon injury that induced for DSS.