Milk is converted to curd by certain bacteria called Lactic Acid Bacteria (LAB). Lactobacillus comes under this category. These bacteria, during the process of curdling of milk, also increase its nutritive value by increasing the content of Vitamin-B12.

Lactic acid bacteria (LAB) and their role in milk fermentation

Lactic acid bacteria (LAB) are a group of bacteria that play a crucial role in the fermentation of milk. They convert lactose, the natural sugar present in milk, into lactic acid through a process called lactic acid fermentation. This fermentation process gives milk its characteristic tangy flavor and transforms it into curd or yogurt.

Conversion of milk into curd

LAB are naturally present in raw milk or can be added as starter cultures. When milk is left at a suitable temperature for fermentation, LAB multiply and convert lactose into lactic acid. The lactic acid lowers the pH of the milk, causing it to curdle and form a solid mass. This solid mass is the curd or yogurt.

Improvement of nutritional quality

LAB not only convert milk into curd but also improve its nutritional quality through various mechanisms:

1. Enhanced digestibility: LAB produce enzymes such as lactase that break down lactose into simpler sugars, making it easier for individuals who are lactose intolerant to digest milk and milk products.

2. Increased protein availability: LAB produce proteases that hydrolyze proteins into smaller peptides and amino acids. This enzymatic action helps in the breakdown of complex proteins, making the amino acids more readily available for absorption in the body.

3. Vitamin synthesis: LAB are capable of synthesizing certain vitamins such as vitamin B12, riboflavin, and folate. These vitamins are essential for various metabolic processes in the body, and their presence in curd enhances its nutritional value.

4. Production of antimicrobial compounds: LAB produce antimicrobial compounds, such as bacteriocins, which inhibit the growth of harmful bacteria. This property of LAB helps in maintaining the hygiene and safety of the fermented milk product.

5. Probiotic effects: Some LAB strains have probiotic properties, meaning they confer health benefits when consumed. They can improve gut health, enhance the immune system, and promote overall well-being.

In conclusion

Lactic acid bacteria (LAB) play a pivotal role in the fermentation of milk, converting it into curd and improving its nutritional quality. LAB enhance the digestibility of lactose, increase protein availability, synthesize vitamins, produce antimicrobial compounds, and exhibit probiotic effects. The consumption of curd or yogurt, rich in LAB, can provide numerous health benefits and contribute to a balanced diet.

Vitamin B12(cyanocobalamine)