Lactobacillus mediated conversion of milk to curd results because of:

Options

A. Coagulation and partial digestion of milk fats
B. Coagulation and partial digestion of milk proteins
C. Coagulation of milk proteins and complete digestion of milk fats
D. Coagulation of milk fats and complete digestion of proteins

Answer

**Step-by-Step Solution:**

1. **Understanding the Role of Lactobacillus:**
- Lactobacillus is a type of lactic acid bacteria that plays a crucial role in the fermentation process of milk into curd.

2. **Lactose Conversion:**
- When Lactobacillus is added to milk, it ferments lactose (the sugar present in milk) and converts it into lactic acid.

3. **Coagulation Process:**
- The lactic acid produced during fermentation lowers the pH of the milk, leading to the coagulation of milk proteins, primarily casein. Coagulation is the process where proteins clump together and form a solid or semi-solid mass.

4. **Partial Digestion of Milk Proteins:**
- Along with coagulation, the action of Lactobacillus also leads to the partial digestion of milk proteins. This process enhances the nutritional value of the curd formed.

5. **Formation of Curd:**
- The combination of coagulation and partial digestion of proteins results in the formation of curd (or yogurt), which has a higher nutritional value compared to milk, particularly in terms of vitamin B12 content.

6. **Evaluating the Options:**
- Now, let's evaluate the provided options:
- **Option A:** Coagulation and partial digestion of milk fats - Incorrect, as fats are not digested in this process.
- **Option B:** Coagulation and partial digestion of milk proteins - Correct, as both processes occur.
- **Option C:** Coagulation of milk protein and complete digestion of milk fats - Incorrect, as fats are not involved.
- **Option D:** Coagulation of milk fats and complete digestion of proteins - Incorrect, as fats are not involved and proteins are only partially digested.

7. **Conclusion:**
- The correct answer is **Option B: Coagulation and partial digestion of milk proteins.**

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