Comparison of beta-Glucan Content in Milled Rice, Rice Husk and Rice Bran from Rice Cultivars Grown in Different Locations of Thailand and the Relationship between beta-Glucan and Amylose Contents

beta-glucan is a dietary fiber that is beneficial to human health, and its content varies according to its different parts, type of cereal grain, and growing environment. In this study, the beta-glucan of milled rice, rice husk, and rice bran fractions, as well as the amylose content of milled rice fraction, from 38 selected rice-paddy grains from six regions of Thailand were quantitatively determined. The milled rice of the Sakon Nakhon (SN) cultivar grown in the northeast contained the highest beta-glucan content (0.88 & PLUSMN; 0.03%), followed by the milled rice of the Jow Khao Chiangmai (JKC) cultivar (0.71 & PLUSMN; 0.03%) and rice bran of the Sew Mae Jan (SMJ) cultivar (0.67 & PLUSMN; 0.03%) grown in the north. The results reveal that the rice cultivars from each region showing variation in the beta-glucan level in each fraction, which is mainly found in milled rice and rice bran, are similar to those found in other cereal grains, although low amounts are found in the husk. The amylose and beta-glucan contents in the milled rice fraction showed a strong negative correlation (r = -0.805; p < 0.0001). This new information about the beta-glucan content of Thai rice cultivars could be used for the development of cereal-based functional food.