However not all proteins have the some biological value. Biological value can be defined as the percentage of the absorbed nitrogen retained in the body.
Protein quality refers to the ability of a dietary protein to supply the amino acid needs of the body. The fact that a specific food is a rich source of protein does not indicate that the food has any particular value in supporting growth or maintenance. Some proteins are rich in certain essential amino acids, and thus have a high biological value, whereas other proteins are devoid of some of these amino acids or contain them in very small amounts.
For example, gelatin is a protein that is sometimes used in cooking. This protein is available in a pure powdered form; however, the use of gelatin as a food and as the sole source of protein cannot supply the body’s amino acid needs.
In those areas of the world where the main protein source is vegetable protein that lacks certain amino acids, protein deficiency diseases often occur, particularly in children.
A protein with biological value of 70 or more is considered capable of supporting growth, assuming caloric value of the diet is adequate. This means that 70% of the nitrogen absorbed is retained.
What is biological value of protein?
