What starch molecule retrogrades during croissant storage?

Amylopectin is the starch molecule that retrogrades during croissant storage. As a croissant cools and ages, its starch chains gradually realign into more ordered, crystalline structures, contributing to firmness.

Croissant dough contains wheat starch alongside gluten, fat, water, yeast, and sugar. Baking gelatinizes the starch: heat and moisture disrupt the original granule structure. During storage, some of the amorphous starch chains reorganize. In the croissant-storage account, amylopectin retrogradation occurs over days to weeks and draws water into the developing crystalline regions.

That water movement affects more than starch. Moisture shifts away from the gluten network and toward starch, while additional moisture migrates from the crumb toward the crust and surrounding air. The result is reduced starch plasticity, a stiffer gluten network, and a pastry that loses its fresh softness.

Amylose is a reasonable distractor because it is the other major starch component and can also participate in bread staling, especially earlier in the process. But for this croissant-storage question, amylopectin is the named molecule associated with the longer-term retrogradation described in the source. Retrogradation is not simply drying: it is molecular reorganization plus moisture redistribution.