Curd is formed from milk.Milk is coagulated and we get milk.It is called curding.M ilk kept for souring when added with lactic acid bacteria becomes curd.T here r also other ways...!!

Formation of Curd

Introduction
Curd is a dairy product that is formed by the coagulation of milk proteins. It is widely consumed and used in various culinary preparations around the world. The formation of curd involves a series of biochemical and microbial processes that result in the transformation of milk into a thick, creamy, and tangy product.

Coagulation of Milk Proteins
When milk is left to stand undisturbed, it undergoes a process called coagulation, which is the first step in curd formation. Coagulation occurs due to the action of enzymes called rennet or lactic acid bacteria present in the milk. The enzymes cause the milk proteins, mainly casein, to aggregate and form a gel-like structure.

Role of Lactic Acid Bacteria
Lactic acid bacteria, such as Lactobacillus bulgaricus and Streptococcus thermophilus, play a crucial role in the formation of curd. These bacteria ferment lactose, the natural sugar present in milk, into lactic acid. The production of lactic acid lowers the pH of the milk, creating an acidic environment that promotes the coagulation of milk proteins.

Acidification of Milk
As the lactic acid bacteria ferment lactose, the pH of the milk gradually decreases. The decrease in pH causes the casein proteins to unfold and form a network of protein strands, resulting in the thickening of the milk. The acidity also inhibits the growth of harmful bacteria, making the curd a safe and stable food product.

Transformation of Milk into Curd
As the milk becomes more acidic, the protein strands continue to intertwine and form a solid mass. This solid mass is the curd, while the remaining liquid is called whey. The whey is a byproduct of the curd formation process and contains water, lactose, minerals, and some proteins. The curd is then separated from the whey through a process known as draining or straining.

Maturation of Curd
After the curd is separated from the whey, it is typically allowed to mature for a certain period. During this maturation, the lactic acid bacteria present in the curd continue to ferment lactose and produce more lactic acid. This further enhances the flavor, texture, and tanginess of the curd.

Conclusion
The formation of curd involves the coagulation of milk proteins, acidification of milk through the fermentation of lactose by lactic acid bacteria, and the subsequent transformation of milk into a solid curd mass. The curd is a nutritious and versatile dairy product that is enjoyed by many cultures worldwide.