Question

A ghee sample, which tested low for RM value (less than 24) and high for Polenske Value (more than 2), is likely to be adulterated with

• A. Groundnut oil and/or sesame oil
• B. Sunflower oil and/or vanaspathi
• C. Vanaspathi and/or mineral oil
• D. Coconut oil and/or palm oil

Hint:

To identify ghee adulterants from chemical values:
- Low RM + Low Polenske \(\rightarrow\) Common vegetable oils (groundnut, sesame) or Vanaspathi.
- Low RM + High Polenske \(\rightarrow\) Coconut oil or Palm kernel oil (due to high lauric/capric acid content).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Ghee (clarified butterfat) is characterized by a high concentration of short-chain fatty acids (like butyric and caproic acids), which are soluble and volatile.
It also contains moderate amounts of medium-chain volatile fatty acids (like caprylic and capric acids), which are insoluble but volatile.
- TheReichert-Meissl (RM) value measures soluble volatile fatty acids (typical range for pure ghee: 26 to 32).
- ThePolenske value (PV) measures insoluble volatile fatty acids (typical range for pure ghee: 1.5 to 3.0).

Step 2: Detailed Explanation:
When foreign fats or oils are added to ghee, they alter these analytical values based on their fatty acid profiles:
-Vegetable oils and Vanaspathi:
Oils like groundnut, sesame, sunflower, or hydrogenated vegetable fats (vanaspathi) consist mostly of non-volatile long-chain unsaturated or saturated fatty acids.
Adulteration with these fats drastically reduces both the RM value and the Polenske value of the ghee sample.
-Coconut and Palm kernel oils:
These oils contain high concentrations of medium-chain fatty acids, particularly lauric, capric, and caprylic acids.
These fatty acids are steam-volatile but insoluble in water.
Consequently, when ghee is adulterated with coconut or palm kernel oil:
1. The RM value decreases significantly (below 24) because these oils have very low butyric acid content compared to butterfat.
2. The Polenske value increases significantly (above 2.0 or 3.0) because of the high concentration of steam-volatile, insoluble medium-chain fatty acids in these oils.
Therefore, a low RM value combined with an elevated Polenske value is a characteristic indicator of adulteration with coconut or palm-derived oils.

Step 3: Final Answer:
The ghee sample is likely adulterated with coconut oil and/or palm oil, which corresponds to Option (D).