The emulsifying agent present in milk that makes it stable is

Options

A. lactose
B. maltose
C. casein
D. lactic lactic bacilli

Explanation

To determine the emulsifying agent present in milk that contributes to its stability, we can follow these steps:

### Step 1: Understand the Composition of Milk
Milk is an emulsion, specifically an oil-in-water emulsion. This means that fat droplets (oil) are dispersed in a continuous water phase.

**Hint:** Remember that emulsions consist of two phases: the dispersed phase and the dispersion medium.

### Step 2: Identify the Role of Emulsifying Agents
Emulsifying agents are substances that help stabilize emulsions by reducing the surface tension between the two immiscible liquids (oil and water). They prevent the dispersed droplets from coalescing.

**Hint:** Think about what substances can help keep oil and water mixed together without separating.

### Step 3: Recognize the Emulsifying Agent in Milk
In milk, the primary emulsifying agent is a protein known as casein. Casein proteins have hydrophilic (water-attracting) and hydrophobic (water-repelling) parts, which allows them to stabilize the oil droplets in the water.

**Hint:** Consider the types of proteins found in milk and their functions in emulsification.

### Step 4: Evaluate the Options Given
1. **Lactose** - A type of sugar, not an emulsifying agent.
2. **Maltose** - Another type of sugar, also not an emulsifying agent.
3. **Casein** - The correct emulsifying agent present in milk.
4. **Lactic bacilli** - A type of bacteria, not an emulsifying agent.

**Hint:** Look for the option that is a protein and is known for its emulsifying properties.

### Conclusion
The emulsifying agent present in milk that makes it stable is **casein**.

**Final Answer:** Casein