Normal starch consists of two glucans: amylopectin and amylose. Amylopectin is highly
branched molecules with -(14) glycosidic-linked short linear chains connected by -
(16) glycosidic linkages. Amylose is comprised of primarily linear molecules with -
(14) glycosidic linkages; some consist of a few branches. The branch chains of the
amylopectin are packed into a semi-crystalline structure of double helices in the starch
granules (Figure 1) (Jane et al 1997). Amylose is present in an amorphous form intertwined
and interspersed with the amylopectin (Jane et al 1992). Amylopectin and amylose are
synthesized side by side by different enzymes, which are soluble starch synthase and granular
bound starch synthase, respectively (Nakamura 2002). Granular bound starch synthase is
also responsible for the biosynthesis of super-long branch chains of the amylopectin, which
have properties similar to amylose (Yoo and Jane 2002, Inouchi et al 2005). A