Which of the following sources of protein has the highest digestibility?

• A. Lentils
• B. Wheat gluten
• C. Soybeans
• D. Egg white

Answer: (D)

Verified step by step guidance

1. Understand the concept of protein digestibility: Protein digestibility refers to how efficiently the body can break down and absorb the amino acids from a protein source. Proteins with higher digestibility are more readily utilized by the body.
2. Learn about the Protein Digestibility-Corrected Amino Acid Score (PDCAAS): PDCAAS is a method used to evaluate protein quality based on both digestibility and amino acid composition. Egg white has a PDCAAS score of 1.0, which is the highest possible score, indicating excellent digestibility and amino acid profile.
3. Compare the digestibility of the given protein sources: Lentils, wheat gluten, and soybeans have lower PDCAAS scores compared to egg white. Lentils and soybeans are plant-based proteins, which often contain antinutritional factors like phytates that can reduce digestibility. Wheat gluten is also less digestible due to its amino acid composition.
4. Recognize why egg white is the most digestible: Egg white is a complete protein, meaning it contains all essential amino acids in the right proportions. It is also free from antinutritional factors, making it highly digestible and efficient for the body to use.
5. Conclude that egg white has the highest digestibility among the options provided, based on its PDCAAS score, amino acid profile, and lack of antinutritional factors.