Avidin

Avidin is a glycoprotein fraction occurring in egg whites that binds the B-vitamin biotin with extraordinary strength, one of the strongest non-covalent bonds known in nature. Eating large amounts of raw egg white can therefore reduce biotin availability and, in extreme cases, contribute to deficiency. Cooking denatures avidin completely and eliminates the concern, which is why the issue applies only to raw-egg consumption, such as in homemade mayonnaise or protein shakes, and not to cooked eggs. In laboratories, the avidin-biotin bond is exploited in sensitive diagnostic assays, including ELISA formats used in food-allergen and pathogen testing, where its strength gives exceptionally stable detection complexes.