STARCH RETROGRADATION

Starch granules heated in excess water undergo an order-disorder phase transition called gelatinization (1) over a temperature range charact eristic of the starch source. This phase transition is a nonequilibriu m process associated with the diffusion of water into the granule, hyd ration and swelling of the Starch granules, uptake of heat, loss of cr ystallinity, and amylose leaching (1-3). On cooling, the starch chains (amylose and amylopectin) in the gelatinized paste associate, leading to the formation of a more ordered structure. These molecular interac tions are termed collectively ''retrogradation'' and have important te xtural and dietary implications (not covered in this review). This rev iew summarizes the present knowledge on amylose gelation and amylopect in crystallization, and on the factors that influence starch retrograd ation.