Enhancing The Nutrition And Functional Properties Of Rice Protein Via Protein-Protein Interactions

The interactions between proteins determine the structure and properties of the proteins.Toward the improvement of nutrition and functional property of rice protein,this work explored the interaction mechanism between rice protein and proteins which closely related to the food industry.It is expected that the design of the protein-protein complex system will not only strengthen the nutritional value and enhance the health benefits but also improve the originally poor functional properties of rice protein.The main research contents include the interaction mechanism of rice glutelin and casein,the use of glutamine transaminase to prepare casein-glutelin cross-linked products,the preparation of rice protein-wool keratin film the preparation of water-soluble nanoparticles of rice glutelin-glutelin.The results show that:(1)A casein complex own surface dense layer,which is driven by van der Waals forces and hydrogen bonds,is involved in the hydrophobic region of rice glutelin.At the same time,the casein aggregates dissociate to small particle groups including?-casein and ?s2-casein nanoparticles(?20 nm),which are connected by residual calcium phosphate nanoclusters;(2)For cross-linking experiments,when the amount of glutamine transaminase is 15 units per gram of protein,the cross-linking degree of casein-rice glutelin blends is the highest.The digestibility of the cross-linked product is reduced while the rheological properties are more suitable for industrial processing.The blends without transglutaminase treatment are more suitable for dietary formulations,while the prepared cross-linked product is more suitable for drug delivery at specific locations;(3)Rice protein and wool keratin form an anti-folding structure during the adjustment from pH 9 to neutral.The film-forming precursor prepared after adding glycerin still maintains favorable dispersion after thermal treatment,and the film undergoes reorganization of disulfide bonds during the forming process.In terms of mechanical strength,optics,water resistance,and degradation,the rice protein-wool keratin film is superior to the rice protein film prepared under alkaline and the rice protein film incorporated with pectin or malic acid;(4)Rice glutelin extracted from Indica rice and glutelin extracted from Japonica rice were successfully co-dissolved to prepare water-soluble whole glutelin powder(initially 1%,w/v;solubility>90%),it shows favorable reconstitution ability after freeze-drying and simulated spray-drying.The interfacial characteristics and the characterization of the tertiary structure support the proposed solubilization mechanism,that is,the two proteins complete a structural transition from hydrophobic to hydrophilic during the process from strong alkaline to a neutral environment.Studies on protein complexes have shown that there is a diversity of protein-protein interactions both in terms of interface properties and functional properties.This diversity will provide unlimited possibilities for the application of rice protein.