Question

During the process of freeze drying, ice crystals from the food are removed by the process known as :

• A. Sublimation
• B. Vaporization
• C. Re-crystallization
• D. Reverse osmosis

Hint:

Freeze drying is unique because it completely bypasses the liquid water phase, preventing product shrinkage and preserving structural texture.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Freeze drying (lyophilization) preserves food structure and nutrients by freezing water within the food and removing it under vacuum.

Step 3: Detailed Explanation:
During freeze drying:
1. The food is cooled to freeze its moisture content into solid ice.
2. The food is placed inside a low-pressure vacuum chamber.
3. Under high vacuum, gentle heat is applied. The ice crystals transition directly from the solid state to vapor without melting into liquid.
This direct phase change from solid to gas is called

sublimation.
Thus, ice is removed via sublimation.

Step 4: Final Answer:
The correct option is 1, which corresponds to Sublimation.