abstract
To examine the impact of structural characteristics of cooked rice grains on their starch digestibility, a
simulated in vitro gastro-small intestinal digestion technique was applied to intact and homogenised
cooked rice samples. The starch hydrolysis percentage increased during simulated small intestinal digestion,
in which approximately 65% and 24% of the starch was hydrolysed within the first 5 min, for homogenised
and intact cooked rice, respectively. The kinetic constant of homogenised cooked rice, which was
regarded as an estimated digestion rate, was 8 times higher than the intact cooked rice. The homogenised
and intact samples were also examined for any microstructural changes occurring during the
in vitro digestion process using fluorescent and scanning electron microscopy. In the intact samples,
the aleurone layers of the endosperm remained as thin-film like layers during in vitro digestion and thus
may be regarded as less digestible materials that influence cooked rice digestibility.