Abstract: To understand the relationship between grain protein content and rice eating quality, changes on RVA viscosity properties of rice were analyzed through protein removal or disulphide bond disruption. Pre-incubation of flour with trypsin decreased viscosity and the slopes of the linear parts of the curves for each variety. Dithiothreitol(DTT) decreased the peak viscosities of flour at different degrees in various rice varieties, and increased the breakdown viscosities in five of the ten tested varieties. It was suggested that protein influenced viscosity curves through binding water, which increased the concentration of the dispersed and viscous phase of gelatinized starch, as well as the agency of a network linked by disulphide bonds. Protein may affect the amount of water absorption early in cooking, which will influence the eating quality of the cooked rice.

Key words: rice, protein, disulphide bonds, starch, viscosity

摘要： 通过分析蛋白酶或还原剂二巯基苏糖醇（DTT）分别去除稻米蛋白质或打破蛋白质二硫键后，稻米RVA（Rapid Visco Analyzer）特征谱形成和特征值的变化，研究蛋白质对淀粉RVA特征谱的影响，以及对米饭食味品质的作用。在淀粉糊化过程中，蛋白质使RVA特征谱的峰值黏度、冷胶黏度等值升高，改变RVA线性上升段的斜率。蛋白质可能通过二硫键结合形成的蛋白质网络本身和通过吸水减少淀粉水合的有效水量，协同提高糊化多相体系的浓度，增强分散相与黏稠相的互作。蛋白质影响米饭食味品质，可能通过改变米粒的吸水性而起作用。

关键词: 水稻, 蛋白质, 二硫键, 淀粉, 黏滞性