Question

The undesirable components which need to be removed during refining of crude vegetable oils include:

(A) Colouring and odouring matters

(B) Free fatty acids

(C) Gums

(D) Waxes

Choose the correct answer from the options given below:

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

Hint:

Think about the full sequence of refining steps, degumming, neutralising, bleaching, deodorising and dewaxing, and what each one takes out.

Answer 1

The Correct Option is B

Step 1: Refining of crude vegetable oil is done in a series of steps, each one targeting a specific unwanted component left over from extraction.

Step 2: Degumming, usually with hot water or acid, pulls out the gums and phospholipids, so (C) Gums is removed.

Step 3: Neutralisation, treating the oil with an alkali like caustic soda, converts free fatty acids into soap, which is then washed away, so (B) Free fatty acids is removed.

Step 4: Bleaching, using activated earth or carbon, adsorbs the natural pigments, and deodorisation, done under vacuum with steam, strips out the volatile compounds that carry smell and taste, so (A) Colouring and odouring matters is removed.

Step 5: Winterisation, or dewaxing, chills the oil so waxes crystallise out and can be filtered off, so (D) Waxes is removed.

Step 6: Since every one of these four, gums, free fatty acids, colour and odour causing matter, and waxes, is taken out at some stage of refining, the correct choice is (A), (B), (C) and (D), option 2.