Question

Which one of the following gases contributes maximum to dissolved gases of milk?

• A. Oxygen
• B. Nitrogen
• C. Hydrogen
• D. Carbon dioxide

Hint:

Dissolved Gases in Fresh Raw Milk: Maximum Dissolved Gas = CARBON DIOXIDE ($\text{CO}_2$, $> 50\%$ of total gas volume) $>$ Nitrogen ($\text{N}_2$) $>$ Oxygen ($\text{O}_2$).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Dissolved gas equilibria in bovine milk: fresh raw milk drawn from the udder contains 6--10% by volume of dissolved gases, dominated by carbon dioxide ($ ext{CO}_2, pprox 50-60\%$ of total dissolved gases 30--40 mg/L).
Key Formula or Approach:
\[ \text{Dissolved Gases in Fresh Milk (Vol \%): } \mathbf{CO_2 \text{ (4.0--6.0\% by vol / 50--60\% of total gases)}} > \text{N}_2 (1.0 - 1.5\%) > \text{O}_2 (0.1 - 0.2\%) \]

Step 2: Detailed Explanation:
In physical chemistry and gas equilibria of fluid milk:
- Fresh raw milk drawn anaerobically from the udder contains approximately $6\% - 8\%$ by volume of total dissolved atmospheric and physiological gases:
1. Carbon Dioxide ($\text{CO}_2$) (D): Contributes maximum to the dissolved gases (accounting for $50\% - 60\%$ of total dissolved gas volume, typically $3.5\text{ to } 6.0\text{ mL } \text{CO}_2 / 100\text{ mL milk}$ or $30 - 50\text{ mg/L}$). It exists in dynamic equilibrium with carbonic acid and bicarbonate buffer ions ($ ext{HCO}_3^-$).
2. Nitrogen ($\text{N}_2$): Contributes $\approx 30 - 40\%$ ($1.0 - 1.5\text{ mL/100 mL}$).
3. Oxygen ($\text{O}_2$): Contributes $< 5 - 10\%$ ($0.1 - 0.4\text{ mL/100 mL}$).

Step 3: Final Answer:
Therefore, Carbon dioxide contributes maximum to dissolved gases of milk, matching option (D).