Question

Which of the following proteins has highest biological value.

• A. Casein
• B. Soy protein
• C. Whey proteins
• D. Gluten

Hint:

Whey protein is considered a gold-standard dietary protein.
Its biological value of \( >100 \) is the highest of any natural food protein source, surpassing even egg protein (\( 100 \)) and casein (\( 80 \)).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Biological Value (BV) is a measure of the proportion of absorbed protein from a food which becomes incorporated into the proteins of the organism's body.
It reflects how readily the digested protein can be utilized for protein synthesis in the body, which depends heavily on its essential amino acid profile.

Step 2: Detailed Explanation:
Let us compare the Biological Values of the listed proteins:
- Gluten (wheat protein) has a low biological value of approximately \( 50 \) to \( 64 \) due to a deficiency in the essential amino acid lysine.
- Soy protein has a moderate biological value of approximately \( 74 \).
- Casein (the major milk protein) has a high biological value of approximately \( 77 \) to \( 80 \).
- Whey proteins (the soluble proteins of milk, including \(\beta\)-lactoglobulin and \(\alpha\)-lactalbumin) have an exceptionally high biological value of approximately \( 104 \).
They are extremely rich in branched-chain amino acids (BCAAs like leucine, isoleucine, and valine) and sulfur-containing amino acids (cysteine, methionine), which are highly efficient for muscle protein synthesis.
Therefore, whey proteins have the highest biological value.

Step 3: Final Answer:
Whey proteins have the highest biological value among the listed options.