Effects of Ultrasound Processing on the Thermal and Retrogradation Properties of Nonwaxy Rice Starch

In the present research, nonwaxy rice starch suspension (5%, dry basis) was processed by ultrasound. The relationship between temperature and ultrasonication time of rice starch suspension was investigated, and the effects of ultrasound power and time, intensity on the thermal and retrogradation properties of rice starch were evaluated. Thermal and retrogradation properties of rice starch were determined by a differential scanning calorimetry. The results of temperature values showed that temperature increased with ultrasonication time and power and ultrasound intensity; the higher the ultrasound power and intensity, the higher the temperature of rice suspension. The ultrasound thermal effects cause temperature increase and partly starch gelation during ultrasound processing. High ultrasound power and strong intensity can effectively change the onset temperature and enthalpy of rice starch, and change the retrogradation properties of rice starch; however, the low ultrasound power and intensity have less effects on the granule and properties of rice starch. Practical Applications Ultrasound technology is widely used in starch processing. This article shows the effects of ultrasound time, power and intensity on the thermal and retrogradation properties of nonwaxy rice starch suspensions. Ultrasound processing can significantly change the properties of nonwaxy rice starch, and the ultrasound thermal effects cause the temperature increase and partly starch gelation in nonwaxy rice starch suspension during ultrasound processing. The method of high ultrasound power with strong intensity is potentially very useful to produce high-quality modification starch for the starch industry if the thermal effects of ultrasound are avoided.