Community Medicine (PSM) · Nutrition (Macro/Micronutrients, RDA, PEM, Nutritional Programmes)

In assessing the protein quality of a food source, the ratio of essential amino acids to total nitrogen in the food compared to that of a reference protein (usually egg protein) is measured by the:

  • A Chemical score (CS) / Amino acid score
  • B Net protein utilization (NPU)
  • C Protein efficiency ratio (PER)
  • D Biological value (BV)
Correct answer: A. Chemical score (CS) / Amino acid score

Explanation

The Chemical Score (CS) or Amino Acid Score compares the essential amino acid profile of a test protein against that of a reference protein (egg or FAO reference pattern); the limiting amino acid determines the score. Biological Value (BV) measures nitrogen retained/nitrogen absorbed (accounts for digestibility and nitrogen balance). Net Protein Utilization (NPU) = Nitrogen retained/Nitrogen intake (= BV × digestibility). Protein Efficiency Ratio (PER) = weight gain per gram of protein consumed and is used primarily for rat feeding experiments. Chemical score is the simplest, most widely used measure for comparing protein quality in plant vs. animal sources.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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