This is mainly caused by retrogradation of the amylose. Chemical modification of starches can reduce or enhance the retrogradation. Starch retrogradation is mentioned previously in this paper. Amylose, the linear component of the starch, is more susceptible to retrogradation. Dissolved amylopectin starch has a lower tendency of retrogradation (gelling) during storage and cooling. Waxy starches have less retrogradation, resulting in a more stable paste. Asteroids and Kuiper Belt objects (including Pluto) exhibit apparent retrogradation. Retrogradation can expel water from the polymer network. Additives such as fat, glucose, sodium nitrate and emulsifier can reduce retrogradation of starch . Retrogradation is directly related to the staling or aging of bread.