The complementary effect of moisture content and water-to-rice ratio: Low hardness, high viscosity are key to regulating Japonica rice eating quality

We investigated the main and interactive effects of moisture content (MC) and water-to-rice ratio (WR) on the eating quality of Japonica rice and examined the underlying regulatory mechanisms. Eight MC gradients and four WR gradients were established. Thermal pasting properties, texture properties, and sensory quality were evaluated. Analysis of variance, quadratic regression, multiple regression, and partial least squares modeling were employed to analyze the response relationships among the indicators. WR significantly impacted hardness, stickiness, maximum viscosity, and breakdown value. MC significantly affected hardness, maximum viscosity, and breakdown value. Significant interactive effects between MC and WR were observed for stickiness, maximum viscosity, and breakdown value. A partial least squares (PLS) model explained 67.71% of the sensory variance, confirming that instrumental pasting and texture properties, including retrogradation tendency, reliably predict eating quality. MC and WR collectively and complementarily determine cooked rice’s sensory quality by regulating starch pasting and texture. Establishing low hardness, high viscosity as the ideal for superior rice eating quality, this study provides theoretical and practical pathways for precisely controlling rice quality and standardizing its production.