Question

Lyophilization is the technical term for

• A. Vacuum drying
• B. Freeze drying
• C. Drum drying
• D. Osmotic dehydration

Hint:

Drying Terminology: LYOPHILIZATION = FREEZE DRYING (Sublimation under vacuum). Produces porous, heat-undamaged powders with instant reconstitution.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Cryodesiccation physical chemistry: Lyophilization is the process of dehydrating frozen materials via direct ice sublimation below the triple point of water ($T < 0.01^\circ ext{C}, P < 4.58 ext{ mm Hg} / 0.61 ext{ kPa}$).
Key Formula or Approach:
\[ \text{Phase Transition: Solid Ice} \xrightarrow[P < 611.65\text{ Pa}, \; T < 0.01^\circ\text{C}]{\mathbf{Sublimation \text{ (No Liquid Phase)}}} \mathbf{Water \text{ } Vapour} \implies \mathbf{Lyophilization / Freeze \text{ } Drying} \]

Step 2: Detailed Explanation:
In food dehydration and starter culture preservation technology:
- Lyophilization (derived from Greek lyo - 'to loosen/solvent' and phile - 'loving') is the technical and scientific term for Freeze Drying (B):
1. The liquid product (dairy starter culture, pharmaceutical enzyme, or specialized dairy protein) is first completely frozen below its eutectic/glass transition temperature ($-30^\circ\text{ to } -50^\circ ext{C}$).
2. Deep vacuum is applied below the triple point of water ($< 0.61\text{ kPa}$).
3. Primary drying sublimes frozen ice crystals directly into water vapor without passing through the intermediate liquid phase.
4. It preserves heat-sensitive vitamins, volatile aromas, starter bacterial viability, and protein tertiary structures with instantaneous cold-water rehydration capacity.

Step 3: Final Answer:
Hence, Lyophilization is the technical term for Freeze drying, matching option (B).