A STUDY ON CHANGES IN AMYLOSE AND RESISTANT STARCH CONTENTS OF SELECTED RICE VARIETIES BY TRADITIONAL COOKING METHODS

Abstract

Resistant starch (RS) is considered to possess several health benefits. The amylose, RS and their relative changes with Total Starch (TS) in different varieties of rice from Northern Sri Lanka with the different traditional cooking methods were determined. For this study seven each of traditional and improved rice varieties were selected. In order to find the effects of traditional cooking methods, three traditional and two improved rice varieties were selected. Traditional rice variety Thattu Wee, contained the highest RS content. Different cooking methods reduced the RS contents of all the selected rice samples. The traditional rice variety Moddakaruppan, lost the highest amylose content except when pre-soaked and cooked without excess water while cooking with and without excess water led to a decrease in amylose related to TS contents except in Periyavellai. Variation in RS related to TS contents showed different changes with cooking methods and rice varieties. RS related to amylose contents decreased by cooking with and without excess water, except in Bw351 cooked without excess water (where there was no change) and with roasting, while pre-soaking and cooking without excess water increased the contents. Among the three traditional rice varieties selected for cooking, Periyavellai lost the least amounts of amylose and RS but the loss was more than that of Bw351.