What is retrogradation process in starch?
Starch retrogradation has been used to describe changes in physical behavior following gelatinization. It is the process that occurs when starch molecules reassociate and form an ordered structure. Under favorable conditions, a crystalline order appears and physical phase separation occurs.
What happens to starch during retrogradation?
Starch retrogradation is a process in which disaggregated amylose and amylopectin chains in a gelatinized starch paste reassociate to form more ordered structures.
What is starch gelatinization and retrogradation?
Gelatinized starch, when cooled for a long enough period (hours or days), will thicken (or gel) and rearrange itself again to a more crystalline structure; this process is called retrogradation. During cooling, starch molecules gradually aggregate to form a gel.
What causes retrogradation?
Retrogradation is a reaction that takes place when the amylose and amylopectin chains in cooked, gelatinized starch realign themselves as the cooked starch cools.
What is the difference between syneresis and retrogradation?
High amylopectin starches do not retrograde easily. Bread loses water when it goes stale which is considered retrogradiation. however some retrogradiation can be reversed, e.g the bread can be reheated again to regain some of its original texture. Synerisis is the shrinkage of a gel and subsequent loss of liquid.
What happens during retrogradation?
How does the granule size of starch effect retrogradation?
As gelatinized starch ages, chains (and especially amylose) continue to interact to form stronger bonds that eventually lead to formation of crystals (retrogradation). Retrograded starch is less soluble in water and thus less digestible (resistant starch) than raw starch.
What is meant by gelatinisation?
Recap: the process of gelatinisation occurs when starch granules are heated in a liquid, causing them to swell and burst, which results in the liquid thickening. [Note that gelatinisation is different from gelation which is the removal of heat, such as ice cream is set when it is frozen.]
Why sugar can reduce starch Retrogradation?
The effects of low molecular sugars is mainly due to the strong sugar-starch interactions between sugar and starch molecules chains, stabilizing the amorphous region of starch and inhibiting the crystallization of starch molecules in amorphous region.