Question

The reversion process in oil is due to the presence of

• A. Pamitic acid
• B. Oleic acid
• C. Stearic acid
• D. Linolenic acid

Hint:

Edible oils with three double bonds, like linolenic acid (18:3), are highly susceptible to rapid photo-oxidation and flavor reversion, which is why soybean oil requires careful storage away from light.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Flavor reversion is a specific type of oxidative degradation that occurs in refined edible oils when exposed to light, air, or heat.
It is characterized by the development of objectionable off-flavors described as "grassy," "beany," "fishy," or "painty" before the onset of typical rancidity.

Step 2: Detailed Explanation:
Flavor reversion occurs primarily in oils that contain significant levels of linolenic acid, a polyunsaturated fatty acid with three double bonds (\(18:3\)).
Vegetable oils like soybean oil and canola (rapeseed) oil are highly susceptible to flavor reversion because of their naturally high linolenic acid content (typically 7--10%).
Even very low levels of oxygen absorption (as low as 0.1%) can initiate the oxidation of linolenic acid.
This oxidation produces volatile compounds, such as 2-pentenyl furan and various unsaturated aldehydes, which have very low sensory thresholds and produce distinct off-flavors.
In contrast, saturated fatty acids like palmitic and stearic acids, or monounsaturated fatty acids like oleic acid, are highly stable and do not undergo flavor reversion.
Therefore, the presence of linolenic acid is the primary cause of flavor reversion in oils.

Step 3: Final Answer:
The reversion process in edible oils is caused by the presence of linolenic acid.