Question

Given below are two statements:
Statement (I) : Creaming is a phenomenon in which milk fat globules rise during cold storage of milk as per stoke’s law.
Statement (II) : Immunoglobulins increase the rate of creaming by forming fat globule clusters, a phenomenon called ‘cold agglutination’.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are true.
• B. Both Statement (I) and Statement (II) are false.
• C. Statement (I) is true but Statement (II) is false.
• D. Statement (I) is false but Statement (II) is true.

Hint:

Cold agglutination is driven by immunoglobulins (antibodies) in raw milk.
Homogenization and high-heat pasteurization denature these proteins and disrupt this clustering, which is why processed milk does not cream as rapidly.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Creaming is the upward movement of fat globules in milk due to gravity, as milk fat is less dense than the continuous skim milk phase.
This gravity-driven separation can be mathematically modeled by Stoke's Law.

Step 2: Detailed Explanation:
Let us evaluate the statements:
- Statement (I): According to Stoke's Law, the rising velocity of a fat globule is proportional to the square of its radius.
During cold storage of raw, unhomogenized milk, fat globules rise to the surface to form a cream layer.
Thus, Statement (I) is true.
- Statement (II): In cold, raw milk, immunoglobulins (specifically IgM, along with helper lipoproteins) adsorb onto the surface of fat globules.
These immunoglobulins act as cryoglobulins, causing the fat globules to cluster together.
This clustering process is known as 'cold agglutination' or 'flocculation'.
Because a cluster of globules has a much larger effective radius than individual globules, Stoke's Law predicts a vastly increased rate of rising.
This explains why raw milk creams very rapidly at low temperatures.
Thus, Statement (II) is true.
Therefore, both statements are true.

Step 3: Final Answer:
Both Statement (I) and Statement (II) are true, corresponding to option 1.