When starch is mixed with water it swells and forms a gel; with time, the starch components will re-crystallise and squeeze the water out of the gel; this phenomenon is known as retrogradation and is responsible for the staling process in bread.

Gradual irreversible insolubilisation of starch paste with formation of a precipitate or gel depending on concentration. Colloquially known as "set back." Retrogradation is mainly due to the presence of amylose in the starch. The linear amylose molecules are attracted to each other and form bundles of parallel polysaccharide chains by the formation of hydrogen bonds between hydroxyl groups on neighbouring molecules. The tendency of amylose molecules to retrograde is increased by molecular weight reduction to a chain length of around 100 anhydroglucose units. Amylopectin having a branched structure shows little tendency to retrograde.

The act of retrograding, or moving backward.

The periodic geocentrically experienced backward movements of the planets through the zodiac, except for the Sun and Moon.

The state of being retrograde; decline.