Influence of ultrasonic enzyme treatment on the cooking and eating quality of brown rice

Abstract

In this study, a novel processing technology was developed to selectively modify brown rice by combining ultrasound and enzyme action. The microstructure of the brown rice surface and the cooking, hydration, pasting, textural properties and sensory attributes of treated brown rice were investigated. The taste value of cooked rice was also studied using a rice taste analyzer. The ultrasonic-enzyme treatment resulted in a loss in the natural morphology of the rice bran, allowing water to penetrate into the rice kernels easily during cooking. Furthermore, the conversion rate of bound to structured water, which is related to the pasting properties of rice, was significantly increased by ultrasonic-enzyme treatment. Brown rice treated with ultrasonic-enzyme provided the lowest cooking time and the highest peak, hold and final viscosities among the groups investigated. Furthermore, the cooked brown rice presented a softer texture and was easier to chew. The taste value of the cooked brown rice increased from 45 to 59 after ultrasonic-enzyme treatment. Sensory analysis showed that odor and flavor of the cooked brown rice were also significantly improved (p < 0.05). All these results indicate a great improvement in eating quality. Thus, ultrasonic-enzyme treatment can be used to produce quick-cooking brown rice with high quality.