Question

Decrease in smoke point is the indication of

• A. High shelf- life oil
• B. Low quality of oil
• C. High quality of oil
• D. No relation with quality

Hint:

The smoke point of an oil is inversely proportional to its free fatty acid (FFA) content.
High FFA levels lower the smoke point, indicating that the oil has degraded and is of low quality.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The smoke point is the temperature at which an oil or fat begins to break down, producing a continuous, visible bluish smoke.
It is a key quality and safety parameter for culinary fats, particularly during deep-fat frying.

Step 2: Detailed Explanation:
During heating, frying, or improper storage, vegetable oils undergo chemical degradation through oxidation, polymerization, and thermal hydrolysis.
In the presence of moisture from food, triglycerides are hydrolyzed to produce free fatty acids (FFAs), diacylglycerols, and monoacylglycerols.
Free fatty acids have a much lower molecular weight and a significantly lower boiling point than intact triglycerides.
As the concentration of free fatty acids increases in the oil, the smoke point drops significantly.
Therefore, a lower smoke point is a direct indicator of thermal degradation, hydrolytic rancidity, and overall low oil quality.
Using oil with a decreased smoke point can produce unpleasant off-flavors, generate harmful volatile compounds like acrolein, and increase the risk of fire.
Thus, a decrease in the smoke point indicates low oil quality.

Step 3: Final Answer:
A decrease in the smoke point is a reliable indicator of low quality in edible oils.