Question

Unit operations those are performed for refining of crude vegetable oils includes:
(A). Pasteurization
(B). Winterization
(C). Bleaching
(D). Neutralizing
Choose the correct answer from the options given below:

• A. (B) and (D) only.
• B. (A), (B) and (D) only.
• C. (B), (C) and (D) only.
• D. (C) and (D) only.

Hint:

Eliminate any option containing Pasteurization (A), as it is strictly a preservation technique for aqueous liquid foods (primarily dairy and juices), leading directly to option (C).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Crude vegetable oil contains impurities such as free fatty acids, color pigments, phosphatides, and waxes.
Refining processes are implemented to remove these undesired components to make the oil edible and stable.

Step 3: Detailed Explanation:
The standard processes for refining vegetable oil are:
-

Neutralizing (D): Uses alkali to remove free fatty acids as soapstock.
-

Bleaching (C): Uses bleaching earths/clays to remove natural coloring pigments and trace metals.
-

Winterization (B): A cooling process used to crystallize and remove waxes and high-melting-point triacylglycerols, ensuring the oil remains clear at cold temperatures.

Pasteurization (A) is a thermal preservation treatment used for milk, juices, and liquid foods to kill pathogenic microbes, and is not utilized in vegetable oil refining.

Step 4: Final Answer:
The operations are (B), (C), and (D).