Separation of three types of starch fractions in rice and the microstructures of endosperms before and after gelatinization
YANG Ze min 1,WANG Wei jin 1* ,LAN Sheng yin 2,XU Zhen xiu 2,ZHONG Fang xu 2,WANG Meng 2 (1 College of Plant Science and Technology, 2 College of Life Science and Technology, Huazhong Agriculture University, Wuhan Hubei 430070, China)
The rice ( Oryza sativa L. ) powder can be separated into four components: non starch component, amylose, amylopectin and intermediary fraction. The four components were light yellow dense powder, white loose powder, vitrescence and pellicular materials respectively. Scanning electron microscopic images showed that the non starch component as large dense blocks, amylose as small loose granules, and amylopectin was made up of fine particles with narrow cracks on its cross section. The structure of intermediary fraction was between that of the amylose and amylopectin rather than their simple mixture. The intermediary fraction was made up of coarser particles with broader cracks on its cross section as compared with the structure of amylopectin. Starch granules were more compactly arranged and intensively crystallized in both chalkiness and non chalkiness areas of the superior variety than in the inferior variety. Gelatinization was more complete in both dorsal and ventral sides as well as middle part of the superior variety than the corresponding parts of the inferior variety. Varietal difference in gelatinization of dorsal sides was less distinct than that of middle parts and ventral sides. Superior grains showed smaller variations between its different parts in gelatinization than the inferior ones.