Brown rice (Oryza sativa L.) was subjected to ultrasonic treatment (UT) and three enzymatic treatments (ET) with cellulase, glucoamylase and α‐amylase. All treatments changed pasting properties of brown rice flour and structure of brown rice grain surface, but only UT and α‐amylase treatment (AT) significantly affected starch granules inside the grain. During cooking, water uptake and volume expansion of UT brown rice were higher than those of ET. Both UT and ET decreased hardness of the cooked brown rice from 206.05 N to 192.22–154.02 N in which the AT cooked rice was the softest. Although UT reduced hardness and increased volume expansion, the brown rice from AT had the highest liking score. Principle component analysis also visualized the preferable brown rice from AT. Therefore, AT was considered to potentially become a novel technology for development of high‐quality brown rice. Practical applications Brown rice is normally soaked in water before cooking. Modifying the structure of brown rice by ultrasonic or enzymatic treatment could improve water uptake, volume expansion and texture of the cooked brown rice. Therefore, enzymatic treatment by α‐amylase was recommended to produce the soften brown rice without soaking before cooking.

Brown rice (Oryza sativa Linn.) was subjected to ultrasonic treatment (UT) and enzymatic treatment (ET) with cellulase (CT), glucoamylase (GT), and α‐amylase (AT). UT showed no significant effect on thermal properties, crystalline pattern and, glycemic response of brown rice. AT decreased gelatinization enthalpy from 7.19 g/J (control) to 5.31 g/J and reduced degree of crystallinity from 23.06% (control) to 21.02%. These changes significantly increased glycemic index of AT brown rice. CT and GT had insignificant effect on crystallinity and thermal properties of rice. Both UT and ET decreased hardness of cooked rice from 206.05 to 189.63–148.87 N in which the AT cooked rice was the softest. Both AT and UT were potentially used as novel processes to develop the soften brown rice. However, UT brown rice had lower glycemic response, required shorter cooking time, and was more practically produced in industrial scale than ET brown rice. Practical applications Soaking is the hydration process, which is normally used for brown rice before cooking. However, it is inconvenient and time‐consuming. Results of this study revealed the effects of enzymatic and ultrasonic treatments (UTs) on modifying of the bran layer and changing of physiochemical properties of rice grains. These changes promoted water uptake, reduced hardness, and improved cooking properties of brown rice. In consideration of glycemic response, UT represents good practice in the production of soften brown rice without soaking before cooking.