Question

The process involving reversal of a dispersed amorphous state of starch to an insoluble aggregated or crystalline condition is called ________ .

• A. Gelatinization
• B. Retrogradation
• C. Syneresis
• D. Dextrinization

Hint:

Retrogradation occurs much faster at low temperatures (just above freezing) than at room temperature.
This is why storing bread in the refrigerator accelerates staling compared to storing it in a breadbox.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Starch is a polymeric carbohydrate consisting of amylose and amylopectin.
When starch is heated in water, it undergoes physical transitions that alter its structure and texture.
Understanding these structural changes is essential for controlling food texture and storage stability.

Step 2: Detailed Explanation:
When starch is heated in the presence of water, it undergoes gelatinization.
During gelatinization, the starch granules absorb water, swell, and disrupt their crystalline structure to form an amorphous paste.
As this gelatinized starch paste cools, the kinetic energy of the molecules decreases.
This allows the linear amylose chains (and, to a lesser extent, amylopectin) to realign and form hydrogen bonds.
This realignment causes the starch to transition from a dispersed, amorphous state back to an ordered, crystalline condition.
This process of crystallization and aggregation is called retrogradation.
Retrogradation makes the starch less soluble and can lead to water exclusion from the gel network, a phenomenon known as syneresis.
It is also the primary reaction responsible for the staling of bread and the firming of cooked rice during storage.
Therefore, the reversal to a crystalline condition is retrogradation.

Step 3: Final Answer:
The process involving the transition of dispersed amorphous starch to an insoluble crystalline state is Retrogradation.