<P> Amylose and amylopectin are both components of starch and polysaccharides made from D - glucose units . The big difference between the two is that amylose is linear because it only has αlpha - 1, 4 - glycosidic bonds . Amylopectin on the other hand, is a branched polysaccharide because it has αlpha - 1, 4 - glycosidic bonds with occasional αlpha - 1, 6 - glycosidic bonds approximately every 22 D - glucose units . Glutinous rice is nearly 100% composed of amylopectin (one of the two components that makes up starch) and almost completely lacks its counterpart, amylose, in its starch granules . A non-glutinous rice grain contains amylose at about 10 - 30% weight by weight and amylopectin at about 70 - 90% weight by weight . </P> <P> Glutinous or waxy type of starches occur in maize, sorghum, wheat, and rice . An interesting characteristic of glutinous rice is that it stains red when iodine is added whereas non-glutinous rice stains blue . This phenomenon occurs when iodine is mixed with iodide to form tri-iodide and penta - iodide . Penta - iodide intercalates between the starch molecules and stains amylose and amylopectin blue and red respectively . The gelation and viscous texture of glutinous rice is due to amylopectin being more hygroscopic than amylose, so it has a higher affinity for water . Thus, water enters the starch granule causing it to swell, while the amylose leaves the starch granule and becomes part of a colloidal solution . In other words, the higher the amylopectin content, the higher the swelling of the starch granule . </P> <P> Even though the amylopectin content plays a major role in the defined characteristic of viscosity in glutinous rice, factors such as heat also play a very important role in the swelling since it enhances the uptake of water into the starch granule significantly . It is estimated that the swelling increases at about 10% in volume per 10 ° C temperature increase . </P> <P> The high amylopectin content of waxy or glutinous starches is genetically controlled by the waxy or wax gene . Its quality of greater viscosity and gelation is dependent on the distribution of the amylopectin unit chains . Grains that have this gene are considered mutants, which explains why most of them are selectively bred to create a grain that is close to having or has a 0% amylose content . The table below summarizes the amylose and amylopectin content of different starches, waxy and non-waxy: </P>

Where does almost all of the rice that the japanese consume come from