Starch Pasting Properties and Structure of a High Amylose Rice Mutant Goamy2

A high amylose rice mutant Goamy2 and its wild type Ilpumbyeo were used to analyze starch pasting properties and structure. There were considerable differences in physico-chemical characters and pasting properties between the high amylose mutant Goamy2 and its wild type Ilpumbyeo,as well as their water soluble and insoluble starch structure according to the results of Size Exclusion Chromatography(SEC). The cold water soluble components of rice flour of the mutant Goamy2 were mainly smaller molecules with the degree of polymerization(DP) of DP141 to DP2. The cold water soluble components of the wild type Ilpumbyeo were bigger molecules and the proportion of branched chains with the degree of polymerization of DP4100 to DP64 was high(33.3%). The hot water soluble starch of Goamy2 were mainly amylose,and the ratio of amylose to amylopectin was 4∶1 approximately,whereas for the hot water soluble starch of Ilpumbyeo,amylose and amylopection were both nearly a half. The ratios of long chains to short chains in hot water soluble amylopectin of the mutant and the wild type varied,being 0.67 and 0.32,respectively. The hot water insoluble starch of both two varieties were mostly amylopectin,and the proportion of amylose were less than 5%. The chain of the hot water insoluble amylopectin in the wild type was mainly short chains,with a proportion of short chains of 72.5%,whereas for the mutant,the proportion of long chains was close to the proportion of short chains.