Question

Which of the following factors does not influence the heat coagulation of proteins during the manufacture of Khoa

• A. Acidity of milk
• B. Concentration of the casein
• C. Salt balance
• D. Amount of fat

Hint:

Remember the difference between chemical coagulation and physical texture:
- Acidity, casein concentration, and salt balance directly regulate the chemical heat-stability of milk proteins.
- Fat acts as a physical lubricant in the product, affecting mouthfeel but not the chemical coagulation of the proteins.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Khoa is a traditional Indian desiccated dairy product prepared by continuously boiling and concentrating milk in an open pan until it reaches a semi-solid consistency.
During this process, the milk proteins (caseins and whey proteins) undergo thermal denaturation and heat-induced coagulation, forming the characteristic grainy texture of Khoa.

Step 2: Detailed Explanation:
Let us evaluate the factors that influence the heat coagulation of milk proteins:
-Acidity of milk:
Increased acidity lowers the net negative charge on the casein micelles, reducing electrostatic repulsion and promoting rapid heat coagulation.
-Concentration of casein:
As water is evaporated during boiling, the concentration of casein increases.
This increases the collision frequency between protein molecules, accelerating their aggregation.
-Salt balance:
The ratio of divalent cations (calcium and magnesium) to anions (phosphate and citrate) regulates the stability of casein micelles.
An imbalance (e.g., high calcium levels) destabilizes the micelles and promotes heat coagulation.
-Amount of fat:
Milk fat exists as dispersed globules surrounded by a fat globule membrane.
While fat contributes to the rich body, yield, and smooth texture of Khoa, it does not chemically influence the heat coagulation kinetics of the proteins.
The proteins undergo thermal coagulation in the continuous aqueous phase regardless of the fat concentration.
Therefore, the amount of fat is the factor that does not influence protein coagulation during processing.

Step 3: Final Answer:
The factor that does not influence the heat coagulation of proteins during Khoa manufacture is the amount of fat, which corresponds to Option (D).