Question

The destabilization of cream in hot coffee is commonly known as

• A. Coagulation of cream
• B. Feathering of cream
• C. Clotting of cream
• D. Denaturation of cream

Hint:

Cream Processing Defects: FEATHERING OF CREAM = Curdling/flocculation in hot coffee. Prevented by addition of buffering salts (Dipotassium Phosphate $\text{K}_2\text{HPO}_4$ Sodium Citrate).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Colloidal instability in hot acidic beverages: feathering is the flocculation, curdling, and floating of white flake/feather-like protein-fat aggregates when coffee cream is added to hot, acidic coffee ($T > 80^\circ ext{C}, ext{pH} < 5.0$).
Key Formula or Approach:
\[ \text{Feathering Tendency} \propto \frac{[\text{Ca}^{2+} + \text{Mg}^{2+}]_{\text{Water/Coffee}} \times \text{High Temp}}{[\text{Citrate} + \text{Phosphate}]_{\text{Cream}} \times \text{pH}} \implies \mathbf{Feathering \text{ Defect}} \]

Step 2: Detailed Explanation:
In the physical chemistry of coffee cream and homogenized dairy emulsions:
- Feathering of Cream (B): The specific dairy technical term describing the spontaneous destabilization, curdling, and appearance of floating, serrated, curd-like flakes or 'feathers' when cream is poured into hot coffee.
- It is triggered by the synergistic combination of:
1. High Coffee Acidity (Low pH $< 5.0$): Brewed coffee acids bring micellar caseins close to their isoelectric precipitation threshold ($4.6$).
2. High Water Hardness: Calcium and magnesium ions in brewing water bridge casein phosphoserine residues.
3. High Temperature ($> 80^\circ - 85^\circ ext{C}$): Rapid thermal denaturation accelerates colloidal collapse.
- It is controlled commercially by homogenizing cream in two stages and adding dipotassium phosphate sodium citrate buffer stabilizers.

Step 3: Final Answer:
Therefore, destabilization of cream in hot coffee is known as Feathering of cream, corresponding to option (B).