The rate of retrogradation can be modified by changing the storage temperature for
nucleation, propagation, and maturation of starch crystallites (Slade and Levine 1987). The
nuclei of the starch crystallites form more rapidly at a lower temperature (close to the glass
transition temperature), whereas the propagation of the starch crystallites is greater at a
higher temperature (close to the melting temperature). Water molecules are required as
plasticizers to lower the glass transition temperature of the starch molecules and to increase
the mobility of starch molecules (Zeleznak and Hoseney 1987, Jang and Pyun 1997, Liu and
Thompson 1998). The maximum degree of starch retrogradation is achieved at an
intermediate moisture content (50-60%).