Retrogradation is the regression of previously gelatinized starch. This happens mainly with the amylose contained in the starch , as this, unlike amylopectin , is not made up of a three-dimensional glucose network and therefore cannot fix the water as well.
Retrogradation is the primary cause of baked goods becoming stale . In the flour contained starch are thereby physically bound the liquid partially again and goes into a crystalline state (z. B. starch granules). The resulting stale pastries take on a soft, foam-rubber-like consistency.
The retrogradation of starch is strongly promoted by low temperatures. Between –7 and +7 ° C, aging increases by a factor of three. As the retrogradation around freezing point is particularly rapid, fresh baked goods should not be stored in the refrigerator. The hardening effect can be delayed by adding fats, emulsifiers and α-amylase.
- Waldemar Ternes , Alfred Täufel, Lieselotte Tunger, Martin Zobel (eds.): Food Lexicon . 4th, comprehensively revised edition. Behr, Hamburg 2005, ISBN 3-89947-165-2 . Page 1561
- Hans-Albert Kurzhals: Lexicon of food technology. Volume 1: A-K ; Volume 2: L- Z. Behr's Verlag, 2003, ISBN 3-86022-973-7 .