Subtopic: Freezing curves and ice crystal morphology
Question Statement:
Which of the following statements regarding food freezing physics is/are TRUE?
Options:
(A) Rapid freezing produces numerous small intracellular ice crystals, preserving cellular membrane integrity and minimizing drip loss upon thawing
(B) Slow freezing forms large extracellular ice crystals that rupture cell walls and cause extensive texture degradation
(C) Freezing point of foods is lower than $0^\circ\text{C}$ due to freezing point depression caused by dissolved solutes (sugars, salts)
(D) Thermal conductivity of ice is approximately 4 times higher than that of liquid water ($2.2\text{ W/m K}$ vs $0.6\text{ W/m K}$)
Answer Key:
A, B, C, D
Step-by-Step Solution & Explanation
All four statements are core principles of food freezing science:
1. Fast freezing yields tiny intracellular crystals (A).
2. Slow freezing yields large intercellular crystals causing cell puncture (B).
3. Solutes depress initial freezing points to $-0.5$ to $-3^\circ\text{C}$ (C).
4. Ice has four-fold higher thermal conductivity than water ($2.22$ vs $0.59\text{ W/m K}$), which is why frozen layers conduct heat faster (D).
All options A, B, C, D are true.