Question

The temperature at which the granules begin to swell rapidly and loose birefringence is called .......

• A. Retrogradation temperature
• B. Gelatinization temperature
• C. Cooking temperature
• D. Boiling temperature

Hint:

Remember: Loss of Birefringence = Gelatinization.
This is one of the most fundamental reactions of carbohydrates in food processing and is crucial for baking, thickening, and starch paste stability.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Starch granules are insoluble in cold water and possess a highly ordered, semi-crystalline structure that exhibits a characteristic optical property known as birefringence under polarized light.
Key Principle:
When starch is heated in the presence of excess water, the intermolecular hydrogen bonds holding the amylose and amylopectin chains together are disrupted, allowing water to penetrate the amorphous regions.

Step 2: Detailed Explation:
As heating continues, the starch granules absorb water and swell irreversibly.
During this swelling process, the crystalline regions are dismantled, resulting in the permanent loss of the radial micellar structure.
This loss of order is observed microscopically as the loss of birefringence (disappearance of the Maltese cross under polarized light).
The temperature at which this structural collapse begins and proceeds rapidly is defined as the gelatinization temperature.
This temperature range is characteristic of the botanical origin of the starch (e.g., corn, potato, wheat).
Retrogradation is the opposite process, where starch molecules reassociate upon cooling to form a semi-crystalline gel structure.

Step 3: Fil Answer
Thus, the gelatinization temperature is the correct term for the temperature at which starch granules swell rapidly and lose their birefringence.