Question

Assertion (A): Amylose is more susceptible to retrogradation. Reason (R): It is not due to its linear structure.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Understanding the structural differences between amylose and amylopectin is key to explaining their behavior during retrogradation processes.

Answer 1

The Correct Option is C

Step 1: Concept
Amylose and amylopectin are two main components of starch. Amylose consists of linear chains of glucose units linked by α(1→4) glycosidic bonds, while amylopectin has a branched structure with additional α(1→6) linkages. Retrogradation is the process where cooked starch molecules rearrange to form hydrogen-bonded structures, leading to a decrease in solubility and an increase in viscosity over time. This phenomenon is crucial for understanding changes in food texture after cooking.

Step 2: Meaning
Assertion (A): Amylose is more susceptible to retrogradation. Reason (R): It is not due to its linear structure.

Step 3: Analysis
Amylose, being a linear polymer of glucose units, has fewer hydrogen-bonding sites compared to amylopectin, which has a branched structure. The lack of branching in amylose means that the chains can pack more closely together, facilitating retrogradation and leading to faster and more pronounced changes in texture upon cooling. However, Reason (R) states that retrogradation is not due to its linear structure, which contradicts the established understanding of starch chemistry. Therefore, Reason (R) is incorrect as it fails to explain why amylose is more susceptible to retrogradation based on its structural characteristics.

Step 4: Conclusion
The assertion (A) is correct because amylose is indeed more prone to retrogradation due to its linear structure allowing for easier hydrogen-bonding and close packing. However, the reason provided in (R) does not correctly explain this phenomenon. Final Answer: (C)