Question

The number of milligrams of potassium hydroxide required to neutralize the free fatty acids present in one gram of ghee sample is known as

• A. Degree of acidity
• B. Kirschner value
• C. Acid value
• D. RM value

Hint:

The Acid Value directly measures hydrolytic rancidity in fats. It differs from the saponification value, which measures both free and esterified fatty acids in the sample.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Hydrolytic rancidity in dairy fats like ghee is caused by the lipase-mediated cleavage of ester bonds in triglycerides, releasing free fatty acids (FFAs).
Determining the concentration of these free fatty acids is important for assessing fat quality, processing history, and shelf-life stability.

Step 2: Detailed Explanation:
The concentration of free fatty acids in fat is measured using several standardized chemical values:
Acid Value: This is defined as the number of milligrams of potassium hydroxide (\(\text{KOH}\)) required to neutralize the free fatty acids present in one gram of fat.
The neutralization reaction is represented as:
\[ \text{R-COOH} + \text{KOH} \rightarrow \text{R-COOK} + \text{H}_2\text{O} \] Degree of Acidity: This is a related measure expressed as the volume of \(1\,\text{N}\) alkali solution (in milliliters) required to neutralize the free acids present in \(100\,\text{g}\) of fat.
Reichert-Meissl (RM) Value: This measures the quantity of steam-volatile, water-soluble fatty acids (primarily butyric and caproic acids) in a fat sample.
Kirschner Value: This measures the steam-volatile, water-soluble fatty acids that form soluble silver salts, specifically isolating butyric acid.

Step 3: Final Answer:
Therefore, the number of milligrams of \(\text{KOH}\) required to neutralize the free fatty acids in one gram of ghee is the acid value.