Concept:
Tea processing involves a series of controlled steps to transform green leaves into black tea.
• Withering: Reduces moisture and makes leaves pliable.
• Fermentation (Oxidation): Develops flavor and color.
• Firing: The final heat treatment step.
Step 1: Identifying the role of Firing.
Firing is the process of exposing fermented tea leaves to hot air.
The main objective is to stop the fermentation process by inactivating enzymes.
Step 2: Physical changes during firing.
This process reduces the moisture content of the tea to about 3%.
This allows for long-term storage and prevents microbial spoilage.
Step 3: Terminological equivalence.
In industrial food engineering, the removal of moisture using heat is called Drying.
Therefore, Firing and Drying are synonymous in the context of tea processing.
Final Answer: (D)