Question

Hydrogenation of oils decreases their nutritional quality by -

• A. Increasing unsaturation of fatty acids
• B. Decreasing saturation of fatty acids
• C. Decreasing level of essential fatty acids
• D. Formation of trans-fatty acids

Hint:

To eliminate trans-fats, modern fat-and-oil technology has transitioned from partial chemical hydrogenation to interesterification and fractionated blending of naturally saturated tropical fats (like palm oil) to achieve the desired semi-solid consistency.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Hydrogenation is a chemical process where hydrogen atoms are added across the double bonds of unsaturated liquid oils in the presence of a catalyst (like nickel) to convert them into semi-solid fats (such as margarine or vanaspati).

Step 2: Detailed Explanation:
- During partial hydrogenation, some double bonds are saturated, but others are chemically isomerized.
- The natural, healthy *cis* configuration of the remaining double bonds is converted into the unnatural, stable trans-fatty acid configuration.
- Clinical studies have established that dietary trans-fatty acids significantly increase the risk of coronary heart disease by raising LDL ("bad") cholesterol levels and lowering HDL ("good") cholesterol levels in the blood.
- While hydrogenation does decrease essential fatty acids (such as linoleic acid), the formation of trans-fatty acids is the most significant, hazardous nutritional drawback that has led to strict global regulatory bans on industrial trans-fats.

Step 3: Final Answer:
The nutritional quality is decreased primarily due to the formation of trans-fatty acids, which corresponds to option (D).