Question

Milk of very low heat stability due to a high concentration of \(\text{Ca}^{2+}\) arising from low citrate content is termed as:

• A. Recknagel phenomenon
• B. Utrecht phenomenon
• C. Eutrecht phenomenon
• D. HCT phenomenon

Hint:

Remember: Utrecht phenomenon = Low Citrate \(\rightarrow\) High Free \(\text{Ca}^{2+}\) \(\rightarrow\) Extremely Low Heat Stability.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The heat stability of milk is governed by the salt balance among calcium, magnesium, phosphate, and citrate ions.
An imbalance can lead to rapid coagulation of milk proteins during thermal processing.

Step 2: Detailed Explanation:
- The Utrecht phenomenon describes a specific physiological anomaly in milk characterized by extremely poor heat stability.
- This condition occurs when the milk contains an abnormally high concentration of ionic calcium (\(\text{Ca}^{2+}\)), which is often caused by a deficiency in citrate or phosphate ions.
- Citrate normally acts as a chelating agent that sequesters calcium ions.
- When citrate is low, the excess free \(\text{Ca}^{2+}\) ions neutralize the negative charges on casein micelles, reducing their electrostatic repulsion and making them highly susceptible to heat-induced coagulation.
Let us clarify other terms:
- Recknagel phenomenon: The gradual increase in the specific gravity of freshly drawn milk over several hours due to air escape and fat crystallization.
- HCT phenomenon: Refers to the Heat Coagulation Time profile of milk.

Step 3: Final Answer
This specific low heat stability condition is known as the Utrecht phenomenon.