Question

Which one of the following belongs to Lye peeling?

• A. Peeling with knife
• B. Mechanical peeling
• C. Heating in boiling water
• D. Dipping in boiling NaOH

Hint:

"Lye" is the chemical synonym for Sodium Hydroxide (NaOH).
Associating the word "Lye" with "NaOH" instantly points to the correct chemical peeling agent.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Peeling is a crucial unit operation in food preservation and processing to remove inedible or tough skin from fruits and vegetables.
There are several methods, including manual, mechanical, thermal, and chemical peeling.

Step 2: Detailed Explanation:
Let us define the peeling methods:
Peeling with a knife is a manual/hand-peeling method.
Mechanical peeling utilizes machines like abrasive rollers or blades to scrape off the skin.
Heating in boiling water is a thermal peeling method, often called scalding or blanching.
Lye peeling is a chemical peeling method.
It involves dipping fruits or vegetables into a hot, dilute solution of sodium hydroxide (NaOH), which is commonly referred to as "lye".
The concentration of NaOH is usually kept between 1% and 2%, heated near boiling point (around 93--100$^\circ$C).
The alkaline chemical dissolves the pectin in the skin's middle lamella, allowing the skin to wash away easily under high-pressure water jets.
Therefore, dipping in boiling NaOH belongs to lye peeling.

Step 3: Final Answer:
Lye peeling refers to dipping in boiling NaOH.