Development of Resistant Milled Rice

Abstract

The study of development of resistant milled rice aimed to evaluate effects of cooking method, degree of cooking and storing at chilling temperature on qualities and resistant starch content of high amylose rice (variety RD 31). Milled rice was boiled and cooked using rice cooker until 30% and 90% degree of cooking, storing at chilling temperature (4±2 ^oC) for 0, 3, 7, 14 and 21 days and dried at 50 ^oC using hot air tray dryer. Resistant rice grain had bulk density of 0.74-0.84 g/cm³, which was close to milled rice. Cooking time and whiteness index were less than those of milled rice. Whereas water absorption and cooked rice hardness were more than those of milled rice. Reduction of paste viscosity was observed. Changes of viscosity were comparable to those of pre-gelatinized flours except resistant rice grain cooking with rice cooker at 30% degree of cooking. Cooking and drying processes decreased resistant starch content (RS) of milled rice from 15.40 g/100g to 5.61-7.08 g/100g. However, storing cooked rice at chilling temperature for 21 days before drying enhanced RS to 21.32 and 21.67 g/100 g for resistant rice grain prepared by boiling and cooking with rice cooker, respectively. Cooking at 30% contributed higher RS than those of 90%.