Subtopic: Processing of seeds, spices, fruits and vegetables
Question Statement:
In cryogenic grinding of spices (such as black pepper and cardamom), liquid nitrogen ($-196^\circ\text{C}$) is pre-mixed with spices prior to milling primarily to:
Options:
(A) Embitter the product below its glass transition temperature ($T_g$) to avoid heat-induced loss of volatile aromatic essential oils and screen clogging
(B) Completely freeze-dry the spices by sublimating all water into ice vapor
(C) Synthesize artificial terpene flavoring compounds by chemical catalysis
(D) Sterilize the spice against bacterial endospores without physical crushing
Answer Key:
A
Step-by-Step Solution & Explanation
Liquid nitrogen chills spices below their brittle transition temperature ($T_g$), preventing oily spices from becoming gummy and blinding screens, while eliminating milling heat that evaporates volatile aromatic terpenes and essential oils.