Nutrition and food chemistry — Which specific compound present in raw egg whites binds biotin and can cause a syndrome resembling vitamin B (biotin) deficiency if consumed in large amounts without cooking?

Introduction / Context:
Raw egg white contains several proteins with distinct biochemical effects. One of them, avidin, has a high affinity for the B-complex vitamin biotin. Understanding this interaction is important in nutrition and food safety because persistent, heavy intake of raw egg whites can induce signs mimicking a vitamin B (biotin) deficiency.

Given Data / Assumptions:

• The question addresses a compound in raw egg white.
• Biotin is a water-soluble B vitamin (vitamin B7) required for carboxylase enzymes.
• Cooking can denature many egg white proteins.

Concept / Approach:
Avidin is a tetrameric glycoprotein in egg white that binds biotin extremely tightly (sub-nanomolar dissociation). When avidin is intact (as in raw egg whites), it sequesters dietary biotin in the gut, preventing absorption. Over time, in extreme dietary patterns, this can cause clinical signs of biotin deficiency, such as dermatitis, alopecia, and neurological symptoms. Heat from cooking denatures avidin, releasing biotin and preventing this effect.

Step-by-Step Solution:

Verification / Alternative check:
Food science texts and clinical nutrition references consistently cite avidin–biotin binding as the mechanistic basis for the so-called “egg-white injury,” resolved by cooking, which denatures avidin.

Why Other Options Are Wrong:

• Betabindin: not an established egg-white protein linked to biotin binding.
• Ovalbumin: major storage protein; does not tightly bind biotin.
• Albumin (serum albumin): not the specific egg white factor responsible for biotin sequestration.

Common Pitfalls:
Assuming any egg white protein causes the deficiency or overlooking the effect of cooking. Only avidin’s extreme affinity for biotin is responsible, and heat inactivation prevents the problem.

Final Answer:
Avidin