Question

Polenske value of ghee represents

• A. Steam volatile and water insoluble fatty acids
• B. Water soluble saturated fatty acids
• C. Steam volatile and water soluble fatty acids
• D. Water insoluble unsaturated fatty acids

Hint:

Reichert-Meissl (RM) value = Steam-volatile + Water-soluble fatty acids (C4, C6). Polenske value (PV) = Steam-volatile + Water-insoluble fatty acids (C8, C10, C12).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The purity and authenticity of milk fat (ghee) are evaluated using several physical and chemical constants.
Among these, the Reichert-Meissl (RM) value and the Polenske value (PV) are important chemical indices.
These values measure the content of volatile fatty acids present in the fat.
Specifically, they differentiate between volatile fatty acids that are soluble in water and those that are insoluble in water.

Step 2: Detailed Explanation:
Milk fat contains a unique and high proportion of short-chain and medium-chain fatty acids (C4 to C14).
When the fat is saponified and acidified, these fatty acids are liberated and can be distilled with steam.
During the distillation process, volatile fatty acids are carried over in the steam.
The Reichert-Meissl value represents the volume of 0.1 N alkali required to neutralize the steam-volatile, water-soluble fatty acids (primarily butyric acid, C4, and caproic acid, C6).
The Polenske value represents the volume of 0.1 N alkali required to neutralize the steam-volatile, water-insoluble fatty acids (primarily caprylic acid, C8, capric acid, C10, and lauric acid, C12).
This distinction is crucial because vegetable fats or animal body fats contain very low amounts of these volatile fatty acids.
Therefore, the Polenske value is a measure of steam-volatile and water-insoluble fatty acids.

Step 3: Final Answer
The Polenske value of ghee represents the steam-volatile and water-insoluble fatty acids.