Research The Preparation And Properties Of Rice Bran Protein-whey Protein Modification Graft Material

With the rice bran protein, whey protein as raw material, the alkaline protease for two proteins in restrictive hydrolysis in order to improve the functional properties of rice bran protein and whey protein and reduce the antigenicity of whey protein, The glutaminase (TGase) was carried out in the crosslinking processing for the modification of rice bran protein and whey protein, in order to obtain high features and quality protein polymer hypoallergenic.In order to avoid damaging the rice bran protein structure and producing too much bitter peptides, at the same time improve the solubility and emulsification, emulsifying stability, foamability, foam stability of rice bran protein functional properties, analyzing its functional properties under the low hydrolysis degree (DH< 14); the results show that the rice bran protein functional properties have greatly improved after the limitation of the alkaline protease hydrolysis. Eventually determine DH 4 late rice bran protein modification for the experimental materials, the protein solubility, foaming ability and foam stability, emulsification, emulsifying stability of the rice bran were respectively increasing 34.55%; 100%; 4.35%; 29.1%; 11.23%.In order to improve the functional properties and reduce the antigenicity of whey protein, at the same time avoid damaging the destruction of whey protein structure and produce large numbers of bitter peptides, restrict whey protein hydrolysis (DH) of 14 or less, To explore the changes of its functional properties and antigenicity. Results show that after the limitation of the alkaline protease hydrolysis of whey protein functional properties have been improved, the antigenicity slash. Eventually determine DH 4 whey protein modification for later experiment materials,through the degree of hydrolysis whey protein solubility, foaming ability and foam stability, emulsification and emulsion stability were respectively increased 8.56%; 20%; 11.11%; 46.94%; 11.56%.The antigenicity of A-LA and B-Lg reducing 40.60%,51.82%.Optimized by single factor experiment for TGase crosslinked rice bran protein-whey protein modification conditions, with OPA formaldehyde method (paes) determinate the free amino content as index for crosslinking degree, foaming and emulsifying properties as the characterization of graft material features, optimization of reaction time, enzyme amount. pH value, rice bran protein-whey protein modification ratio, reaction temperature, the optimum reaction conditions, the optimal condition is:the reaction time is 4 h, the adding amount is 20 u/g, pH= 8, rice bran protein, whey protein modification ratio is 2:1, reaction temperature is 45?,In this condition, the properties of the grafted copolymer were:The foaming properties was:53mL; the foaming stability was:77.36%; the emulsifying property was:0.722; the emulsion stability was:65.04%; the degree of cross-link ing was 83.71%.With the Response surface experiment on the basis of single factor optimization of rice bran protein-whey protein modification graft get the best reaction condition, reaction time, proportion of rice bran protein-whey protein modification, pH, reaction temperature as factors; Crosslinking degree as examining index, to get the best preparation conditions as follows:the reaction time is 4.23 h, rice bran protein:whey protein modification ratio is 2:1, pH= 7.58, the reaction temperature is 44.47 ?, the grafting the crosslinking degree of content under the condition is 85.62%.Under the optimum reaction conditions for preparation,Through the process of TGase crosslinking,the properties of rice bran protein-whey protein modification grafted have greatly increased. Immediately the foamability increased by 3.65%; Foam stability increased by 10.84%; Emulsification increased by 34.81; Emulsion stability increased by 26.04%; For the research on the rice bran protein-whey protein modification graft will provide theory basis for application in the field of food processing.With Sepharose CL-6 B gel chromatography system to purificate rice bran protein-whey protein modification graft,Through SDS-PAGE prove that the protein molecular have changed,there have produce a new protein and molecular greatly increased; After SEM, the results showed that rice bran protein-whey protein microcosmic structure have greatly changed; By amino acid analyzer, analysis the nutritional characteristics of new synthetic graft content, the results show that the new synthesis of protein nutritional characteristics than the rice bran protein and whey protein have improved dramatically; DSC prove the denaturation temperature and heat properties have changed.