Subtopic: Preservation of food by cooling and freezing
Question Statement:
Cryogenic immersion freezing utilizing liquid nitrogen (boiling point $-196.0^\circ\text{C}$) provides superior product quality compared to slow air-blast freezing because:
Options:
(A) Ultra-fast cooling rates produce numerous microscopic intracellular ice crystals that do not puncture or disrupt delicate cell wall membranes, minimizing drip loss upon thawing
(B) Liquid nitrogen chemically bleaches all off-colors
(C) It eliminates all microbial spores by nuclear radiation
(D) It dissolves all water into gaseous methane
Answer Key:
A
Step-by-Step Solution & Explanation
Extremely high freezing rates promote high ice nucleation rates with minimal crystal growth, creating tiny uniform crystals inside cells. In slow freezing, large extracellular ice crystals grow, puncturing cellular membranes and causing excessive weep/drip loss.