Question

Given below are four statements:
Statement (I) : Homogenisation breaks down fat globules in milk into smaller entities.
Statement (II) : Homogenisation breaks down fat globules and casein micelles in milk into smaller entities.
Statement (III) : Homogenisation slightly increases viscosity of milk.
Statement (IV) : Homogenisation improves the appearance of milk.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Statement (I) is false, statements (II), (III) and (IV) are true
• B. Statements (I) and (II) are false, statements (III) and (IV) are true
• C. Statements (I), (III) and (IV) are true, Statement (II) is false
• D. Statement (III) is false, Statements (I), (II) and (IV) are true

Hint:

Remember that casein micelles are much smaller than fat globules and are not disrupted by homogenization. Instead, they act as active emulsifiers to coat the newly formed fat surface.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Homogenization is a mechanical process used to reduce the size of fat globules in milk, preventing the separation of a cream layer.
This treatment significantly alters the physical structure and properties of milk.

Step 2: Detailed Explanation:
Let us analyze each statement individually:
- Statement (I): The primary purpose of homogenization is to reduce the average diameter of fat globules from \(3-4\ \mu\text{m}\) to less than \(1\ \mu\text{m}\). This increases the number of fat globules and prevents gravity creaming. Therefore, Statement (I) is true.
- Statement (II): Casein micelles are very small colloidal structures with a diameter of \(0.1-0.2\ \mu\text{m}\). Homogenization pressures do not break down these micelles into smaller units. Instead, casein micelles adsorb onto the newly created, protein-depleted fat globule membranes. Therefore, Statement (II) is false.
- Statement (III): Homogenization increases the total surface area of the fat globules, leading to more adsorption of serum proteins onto the fat surface. This increase in the volume fraction of the dispersed phase slightly raises the viscosity of the milk. Therefore, Statement (III) is true.
- Statement (IV): The increased number of smaller fat globules enhances light scattering, which makes the milk appear whiter and more opaque. Therefore, Statement (IV) is true.
Summarizing these findings, Statements (I), (III), and (IV) are true, while Statement (II) is false.

Step 3: Final Answer:
The correct option is (C), where Statements (I), (III), and (IV) are true, and Statement (II) is false.