Liu Mengqi, Huang Rumeng, Wang Lifeng, Eid Mohamed, Xiong Wenfei
College of Food Science and Engineering/Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China.
Department of Biochemistry, Faculty of Agriculture, Benha University, Moshtohor 13736, Qaliuobia, Egypt.
Foods. 2025 May 14;14(10):1739. doi: 10.3390/foods14101739.
This study addresses the shortcoming of rice protein, which has limited its widespread use as a food ingredient due to its extremely low solubility in neutral aqueous solution. Herein, rice protein (RP) was dispersed in aqueous solutions with different alkali concentrations (0.075 M0.125 M), and then heat-treated (80 °C, 14 h) to obtain a modified RP. The physicochemical properties of the modified RP in neutral aqueous solution and its performance as a microencapsulated wall material were then comprehensively analyzed. The results showed that the solubility of the RP at pH 7.0 could be increased to more than 56.3% by alkali solution combined with moderate heat treatment for 1 h. Further analysis revealed that the enhancement of the RP solubility performance was mainly due to the depolymerization of rice glutenin cluster aggregates, with the average size decreasing to 140~180 nm, which was also accompanied by an increase in net zeta potential. Structural analysis pointed to a significant decrease in the surface hydrophobicity and free sulfhydryl content of the RP after thermal treatment in alkaline solution, while degradation of glutenin subunits (especially for the results of alkaline treatment at higher concentrations) and an increase in random coil content occurred. These physicochemical properties and conformational transitions of the modified RP contributed to its excellent emulsification properties and microencapsulation ability (encapsulation efficiency > 97%). Nevertheless, the redispersing properties of microcapsules prepared with the modified RP as a wall material were significantly weaker than those of sodium caseinate. These findings provide new guidance and insights into the modulation of functional properties and applications of RP.
本研究解决了大米蛋白的缺点，由于其在中性水溶液中的溶解度极低，限制了其作为食品成分的广泛应用。在此，将大米蛋白（RP）分散在不同碱浓度（0.075 M0.125 M）的水溶液中，然后进行热处理（80°C，14小时）以获得改性RP。然后全面分析了改性RP在中性水溶液中的物理化学性质及其作为微胶囊壁材的性能。结果表明，通过碱溶液结合1小时的适度热处理，RP在pH 7.0时的溶解度可提高到56.3%以上。进一步分析表明，RP溶解性能的提高主要归因于大米谷蛋白簇聚集体的解聚，平均尺寸减小到140~180 nm，同时净zeta电位增加。结构分析表明，碱性溶液热处理后，RP的表面疏水性和游离巯基含量显著降低，同时谷蛋白亚基发生降解（特别是较高浓度碱性处理的结果），无规卷曲含量增加。改性RP的这些物理化学性质和构象转变有助于其优异的乳化性能和微胶囊化能力（包封率>97%）。然而，以改性RP作为壁材制备的微胶囊的再分散性能明显弱于酪蛋白酸钠。这些发现为RP功能特性的调控和应用提供了新的指导和见解。
