Rice grain contains mainly starch (-90%) and a small portion of proteins (-6%), lipids (3%) and minerals (-1%). It is the amount and structure of amylose and amylopectin in the starch that mainly influence the cooking and pasting properties of rice. During cooking, in the presence of water, amylose and amylopectin in starch granules interact with lipids and proteins resulting in specific characteristics that are unique to a rice cultivar. Amylose content (AC) primarily controls the texture, appearance and stickiness, while amylopectin dictates the cooking/ gelatinisation temperature of a rice variety. Higher AC (>22%) causes cooked grains to have firm texture and fluffy appearance, with grain remaining separate from each other. Whereas, lower AC (<20%) results in cooked grains to be softer, translucent/ glossy and relatively stickier. In waxy rice, where the AC is <2%, the cooked grains are extremely soft and sticky and hence used only for specialised cuisines. The cooking and eating properties ofa rice cultivar are generally evaluated by analysing its flour gel on a rapid visco-analyser (RVA). Depending upon the type of rice cultivar, with its unique endosperm components, cooked flour-gel shows a specific pasting curve and upon cooling can showdifferent degree of retrogradation, where gelatinised starch reverts back to a semi-crystalline structure (Bao et al, 2006). It has been reported that pasting properties of rice can change if the proportion of lipids, proteins and free-sugars is altered.
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