Kinetic modeling of alkali spreading degree of brown rice flour

This study quantitatively analyzed the alkaline spreading degree of brown rice flour using scanned and binarized images. Transparency increased and the white area decreased over time, enabling the construction of alkaline gelatinization curves. The effects of stirring time, temperature, potassium hydroxide concentration, and moisture content were examined. Gelatinization accelerated with longer stirring and slowed at lower temperatures, while an optimal potassium hydroxide concentration of 3.6 % was identified. Moisture content had little effect, confirming the robustness of the method. The curves were fitted using both sigmoid and exponential models. The sigmoid model yielded K₀ (gelatinization extent), K₁ (half-life), and K₂ (rate constant), while the exponential model provided A (gelatinization extent) and invTau (rate constant). Both models showed high fitting performance (R2 = 0.99, RMSE = 0.71–4.03) and enabled quantitative interpretation of the alkaline gelatinization process. This method enables objective, time-resolved evaluation of alkaline gelatinization behavior, overcoming limits of traditional rice solubility tests.