OP10: Quality Grain, Health, and Nutrition Melting the secrets of gelatinization temperature in rice

Gelatinization is the irreversible melting process of starch. It is an endothermic process, and the peak temperature at which starch absorbs heat is called gelatinization temperature (GT). GT is one of the key traits measured in breeding programs in rice. It is important because it affects the texture of cooked rice and it is said to be related to the cooking time of rice. Given the number of times that rice is cooked in the world every day, selecting rice varieties with low GT represents huge potential savings in fuel consumption. There are several ways to measure GT. The most common method is alkali spreading value (ASV), for which the degree of disintegration of milled rice is graded after immersion in potassium hydroxide for 24 hours. A more modern assay is by differential scanning calorimetry (DSC). This detects the peak temperature absorbed by the flour-water mixture during gelatinization and is thus more precise than ASV. GT has been linked to starch synthse IIa (SSIIa) in numerous studies (Nakamura et al 2002). In starch synthesis, crystalline regions of amylopectin consisting of short chains of DP 6–12 are first elongated by starch synthase I (Fujit