Study On Functional Properties Of Rice Bran Protein And Its Glycosylation Modification

Rice bran is an important agricultural resource with a large quantity.However,it has been regarded as available feed,resulting in a lot of waste of resources.The rice bran protein extracted from rice bran also has extremely high nutritional value and application potential.In this paper,the ultrasonic-assisted alkali method was used to extract rice bran protein from rice bran that had undergone different stabilization treatments,and the physical-chemical properties of rice bran protein were analyzed.Then,the rice bran protein was compared with soybean protein,which was widely used at present,to study the emulsifying properties and the ability of cadmium adsorption of rice bran protein.Finally,different sugars were used to modify the glycosylation of rice bran protein,and the optimal conditions of the reaction were studied to establish the best method for glycosylation modification of rice bran protein.The results of this study were listed as follows:1.The study found that after ultrasonic treatment,the protein extraction rate of rice bran without stabilization treatment was the highest,which reached 57.89%,while the protein purity of rice bran after microwave heating was the highest,which reached 73.49%.The molecular weight distribution of rice bran protein was not affected by stabilization and ultrasonic treatment.After ultrasonic treatment,the emulsifying stability and oil absorption capacity of rice bran protein could be improved by 16.95%and 10.77%,and the content of sulfydryl was increased by 28.99%.In summary,the ultrasound-assisted alkali method was an effective method for extracting protein from heat-stabilized rice bran,solving the problem that rice bran protein was difficult to extract.2.The study found that in terms of emulsifying properties,the rice bran protein emulsions prepared at two concentrations were more stable than the soybean protein emulsions.When the protein concentration was 2%,the particle size(1030 nm)of rice bran protein emulsion using water as the dispersion was smaller than that of soybean protein emulsion(1762 nm).After 7 days of storage,the creaming index of rice bran protein emulsion was 59.26%,lower than that of soybean protein emulsion(82.35%).The interface protein concentration of rice bran protein emulsion was 5.99 mg/m~2,while that of soybean protein emulsion was 3.14 mg/m~2.The excellent emulsifying properties of rice bran protein made it an effective substitute for soy protein,thus solving the problem of protein shortage.In terms of cadmium adsorption,the sulfhydryl content of rice bran protein was higher than that of soybean protein,as a result,the maximum adsorption amount of rice bran protein(25.13mg/g)was higher than soybean protein(16.43 mg/g),and it was more difficult to remove the cadmium bound to rice bran protein.After oxidizing the sulfhydryl groups,it was found that the adsorption capacity of rice bran protein and soybean protein decreased by 49.6%and43.7%.The excellent cadmium adsorption capacity of rice bran protein made it an effective solution to the increasingly serious cadmium pollution problem.3.The study found that the glycosylation reaction significantly improved the solubility and emulsifying properties of rice bran protein.Inulin had the best modification effect on rice bran protein,with a maximum emulsifying activity of 126.5 m~2/g,and compared with control group,the maximum emulsifying stability was 2.21 times higher.The emulsion was more stable,with an emulsion index of 10.82%after seven days of storage.The best conditions for preparing conjugates were as follows:temperature 90℃,mass ratio 1:1,and reaction time was 60 min.Inulin-rice bran protein complex could fully solve the application limitation of rice bran protein and expand the application space.