2008 Volume 77 Issue 1 Pages 61-68
Starch digestibility and texture of rice were studied in 58 rice cultivars and lines in the IRRI core collection and rice germplasm bank of Gunma Agricultural Technology Center. The principal component analysis was applied to evaluate the in vitro starch digestibility with α-amylase in milled brown rice and physicochemical properties related to texture. Eleven physicochemical properties were analysed by principal component analysis. Of the total variation of 11 characters, 49, 17, 14 and 9% were accounted for by these first 4 principal components, respectively, and so 90% could be explained by the 4 components. The factor loading suggested that the first principal component was a factor which was concerned with starch hydrolysis rate. The second principal component was closely related to the starch degradation rate, the third to the amount of the digestible fraction, and the fourth was to the content of protein in brown rice. The distribution of principal component score showed that the culivars with a low Glycemic Index (GI) have slow starch degrading properties and superior texture. The GI was significantly correlated with amylose content and the peak value measured with a rapid visco analyzer (RVAsuper3). These results contribute to development of the cultivars which have a low GI with good eating quality.
