Question

Casein present in milk. What is casein?
A)Bacterium
B)Sugar
C)Protein
D)Fat

Answer 1

Hint: Casein are mainly found in mammalian milk, the highest quantity comprising 80% in cow's milk and between 20% and 45% in human milk. Buffalo and Sheep milk have a higher concentration casein content than other types of milk with human milk having a particularly low concentration of Casein.

Complete answer:
Casein is a group of phosphoproteins (contains phosphorus attached with protein).This component of milk has a wide variety of uses, whether being a major component of cheese or as a food additive. The most common form that is usually present is sodium caseinate. It undergoes phase separation in milk to form colloidal casein micelles, a variety of bimolecular condensate. Casein has a high quantity of the proline residue. There are no disulfide bridges present.

Now let us find solution from given options:
Bacterium : The bacteria namely Lactobacillus is present in the milk. It helps to convert milk to curd when acidic conditions are provided to it.
Sugar : The milk whether its cow milk or mammals milk contains lactose sugar. It is also called milk sugar.
Protein : Protein is a chain of amino acid that is joined by a peptide group. Casein is a group of phosphoproteins (contains phosphorus attached with protein).
Fat : The fat present in the milk is termed as milk fat.

Hence, the correct answer is option (C)

Note: Some important points about Casein are as All three models of casein structure show influence on micelles and depict them as colloidal particles formed by casein aggregates wound up insoluble k- casein molecules.