Effect of tempering drying on the physicochemical properties of paddy rice

Abstract

To clarify the quantitative relationship between tempering drying parameters and physicochemical properties of paddy rice, as well as optimize the paddy rice drying process, a quadratic regression orthogonal rotational combination test was applied in this study. The initial tempering moisture content of paddy rice, tempering temperature, and tempering duration were test factors, and the amylose starch content, alkali spreading value, and gel consistency were test indicators. It is shown that under the conditions of the initial tempering moisture content of paddy rice was 20.5%, the tempering temperature was 43 °C, and the tempering duration was 3.39 h, the amylose starch content, alkali spreading value, and gel consistency were 17.83%, 7.08 grade and 86.4 mm respectively. The average error between the actual value and the optimized theoretical value was 4.06%, indicating that the regression model was accurate and the physicochemical properties of rice were improved under the optimal process conditions. Then, the visual prediction model for the physicochemical properties of rice was established based on BP (Back Propagation) and GA-BP (Genetic Algorithm-BP) neural networks respectively, and compared with the regression model established by Design-Expert software. The results showed that the root mean square error, mean absolute error, and mean absolute percentage error of GA-BP were lower.