College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Key Laboratory of Fermentation Engineering (Ministry of Education), College of Bioengineering, Hubei University of Technology, Wuhan 430068, China.
Food Res Int. 2023 Feb;164:112306. doi: 10.1016/j.foodres.2022.112306. Epub 2022 Dec 7.
For the limitation of poor solubility and interfacial adsorption capacity of rice protein isolates (RPI), in this work the effects of pH-shifting treatments on the emulsifying properties of RPI were investigated. The results showed that the particle size of the emulsion stabilized by alkaline pH-shifting treated RPI was smaller than that stabilized by acid pH-shifting treated RPI. In addition, the RPI-10 stabilized emulsion showed a more uniform particle size distribution, which was explained by its high emulsifying activity and stability (EAI: 49.5 m/g, ESI: 59.5 min). The interface rheology results showed that the alkaline pH-shifting treatment could promote the protein rearrangement and subsequently formed interface film with higher rate of protein penetration and rearrangement. The quantitative analysis of adsorbed proteins in the RPI-10 stabilized emulsion showed that glutelin-type isoforms as major proteins in RPI were increased at the oil-water interface for their balanced distribution of the hydrophilic and hydrophobic amino acid group. These quantitative and interfacial rheology analysis could improve deep understanding of the interfacial properties of pH-shifting treated RPI, and promote the development of application in grain protein stabilized emulsion.
由于大米蛋白分离物（RPI）的溶解度和界面吸附能力较差，本工作研究了 pH 值变化处理对 RPI 乳化性能的影响。结果表明，由碱性 pH 值变化处理稳定的乳液的颗粒尺寸小于由酸性 pH 值变化处理稳定的乳液。此外，RPI-10 稳定的乳液表现出更均匀的粒径分布，这可以用其高乳化活性和稳定性（EAI：49.5 m/g，ESI：59.5 min）来解释。界面流变学结果表明，碱性 pH 值变化处理可以促进蛋白质的重排，随后形成具有更高蛋白质渗透和重排速率的界面膜。对 RPI-10 稳定乳液中吸附蛋白质的定量分析表明，由于亲水和疏水氨基酸基团的平衡分布，RPI 中的谷蛋白型同工型作为主要蛋白质增加了在油水界面的吸附。这些定量和界面流变学分析可以提高对 pH 值变化处理的 RPI 界面性质的深入理解，并促进谷物蛋白稳定乳液的应用发展。
