Rice contains two types of starch; amylose and amylopectin. High amylose starch is reported to be more resistant than amylopectin to starch digestion because of its compact linear structure.
The molecular weight of amylose is less than 500, 000 while that of amylopectin ranges from 10 to 500 million, Because of the highly branched nature of amylopectin, its properties differ from those of amylose. For example retrogradation is slowed, and gel formation is delayed or prevented.
The amylose/amylopectin ration in milled rice greatly affects the texture and fluffiness of cooked rice. Amylose s a long, straight starch molecule that does not gelatinize during microwave cooking, and hence rice with a greater amylose content tends to be fluffy with separate grains, while low amylose rice are sticky when cooked.
Amylose and amylopectin in rice
