<prompt> Biological value of protein is related toAmino Acid contentEssential amino acid contentN2 contentProtein quality  <response>: The indices are used to assess the nutritional value of proteins. Biological Value BV of Protein : It is the ratio between the amount of nitrogen retained and nitrogen absorbed during a specific interval. Net Protein Utilization NPU: NPU Retained nitrogen intake of nitrogen x 100 Net Dietary Protein Value NDPV: This will assess both quantity and quality of the proteins in the diet. NDPV Intake of N x 6.25 x NPU Protein Efficiency Ratio PER It is the weight gain per gram of protein taken. The essential amino acid content can also be expressed in terms of chemical score mg of amino acid per gram of protein. Ref: Textbook of Biochemistry for Medical Students, 7E DM Vasudevan2013 Pg no 533-534. 