staling

Staling refers to undesirable changes in the texture, flavor, and appearance of baked goods, occurring independently of microbial spoilage. The most noticeable change is the firming of the crumb, where bread loses elasticity and becomes crumbly. This is due to changes in the starch molecules, which aggregate and become more rigid.1

While moisture loss can contribute to this, staling can happen even without significant drying. Heating staled bread to around 60–65°C (140–150°F) can soften it, but it won't fully return to its fresh texture, becoming gummier and more elastic. Starch retrogradation, the cause of staling, can be slowed by adding starch-complexing agents like monoglycerides of fatty acids to the dough.1