Bread in the baking process, the flour amylose part of aging, this is the bread a reason of the elasticity and flexibility of the structure. With the extension of storage time, the straight chain portion of the bread in the branched-chain starch part slowly association, leaving the soft bread gradually hardens, a phenomenon called "change Chen.
Change Chen's speed and temperature. At low temperature (above freezing point) aging rapidly, and bread in the refrigerator than at room temperature to harden the speed is more faster. Therefore, the bread should not be stored in the refrigerator.