Fermentation:
Fermentation is the process by which milk is converted into curd. Lactobacillus bacteria are found in curd.
Lactobacillus bacteria:
- Lactobacillus bacteria are any genus of bacteria that have a rod-shaped body with a non-spore-forming feature and are gram-positive in nature.
- As a byproduct of metabolism, this genus of bacteria can convert glucose into lactic acid.
- This bacterium can be found in a variety of environments, including animal feeds, manure, silage, milk, milk products, and so on.
Fermentation process:
- When one spoon of curd (the precursor curd) is added to milk, the lactobacillus multiplies inside the milk.
- Milk now contains two proteins: whey protein and casein protein.
- When milk is processed into cheese, the whey protein is found in the water, and the casein protein is located in the cheese.
- Casein protein is the globular form of milk protein.
- A chemical reaction occurs during the fermentation process between the lactic acid bacteria and the milk's casein protein.
- Initially, the lactobacillus bacteria use their enzymes to generate ATP from lactose.
- Lactic acid is produced as a byproduct during this process.
- The lactic acid now reacts with the casein protein in milk and denatures it.
- As a result, the globular protein's tertiary and quaternary structures are broken, and the globular protein is converted into a fibrous protein (simple chain protein).
- This fibrous protein begins to thicken the milk, and coagulation of the protein also occurs.
- As a result, the milk turns into curd.