Effect of ultrasonic treatment on the hydration and physicochemical properties of brewing rice

Abstract

In this study, the influence of ultrasonic treatment on the hydration and physicochemical properties of rice was investigated. We found that the water absorption velocity of rice was increased obviously accompanied with the raising of ultrasonic power. Low-field nuclear magnetic resonance (LF-NMR) demonstrated that the mobility of water protons in rice was influenced by ultrasonic treatment, and scanning electron microscope (SEM) micrographs of the rice showed the loosening of matrix and the formation of microspores on rice surface, which may lead to accelerated hydration and decreased hardness. X-ray diffraction revealed that ultrasonic treatment didn't alter the crystalline pattern of rice, but slightly decreased the relative crystallinity. Furthermore, we found that the rice treated with ultrasonic had higher water binding capability, shorter cooking time and better gelatinization degree than untreated one. Our study indicates that ultrasonic treatment is benefit for shortening the soaking and boiling time of rice in Chinese rice wine brewing process.