Question

The process where two crystals that are in a point of contact, join together into one crystal is called as ............ recrystallization.

• A. Iso‐mass
• B. Surface Iso‐mass
• C. Accretive
• D. Migratory

Hint:

Accretive = Contact/Fusion. Migratory = Small dies, big grows. In frozen foods, temperature fluctuations accelerate both processes, leading to large, crunchy ice crystals.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks to identify a specific type of recrystallization mechanism where physical contact between adjacent crystals leads to their fusion into a single, larger crystal.

Step 2: Detailed Explanation:

• Recrystallization is a physical change in a solid where the number, size, shape, or orientation of crystals changes over time without a change in the total mass of the solid phase.

• It is a major cause of quality degradation in frozen foods (e.g., gritty ice cream).

• Accretive Recrystallization: This happens when two or more crystals touch each other and fuse together to form one larger particle. This "sintering" or joining is driven by the reduction in surface energy.

• Migratory Recrystallization (Ostwald Ripening): This occurs through the growth of large crystals at the expense of smaller ones due to differences in vapor pressure or solubility. The smaller ones disappear, and the larger ones get bigger.

• Iso-mass Recrystallization: This involves a change in the shape or internal structure of a single crystal (e.g., sharpening of edges) while the mass remains constant.

• Since the question specifically mentions "point of contact" and "joining together," Accretive is the correct classification.

Step 3: Final Answer: The fusion of contacting crystals is called Accretive recrystallization.