Egg White Protein Denaturation by Acid: Mechanism and Culinary Applications

Adding acid (vinegar, lemon juice, cream of tartar) to egg white (albumin) causes denaturation and coagulation:

1. pH drop → protonation of carboxyl/side chains → disrupts electrostatic interactions stabilizing native conformation.
2. Unfolding: Globular proteins → random coils; hydrophobic cores exposed.
3. Aggregation: Hydrophobic interactions + disulfide bond rearrangement (SH/SS exchange) → insoluble network.
4. Result: Clear viscous liquid → opaque white gel (coagulum).

Culinary Uses

• Meringue: Acid stabilizes foam (prevents overbeating collapse).
• Poached eggs: Acid in water → faster white setting, neat shape.
• Custards/cakes: Acid modifies texture, tenderness.
• Mayonnaise: Acid (lemon/vinegar) aids emulsion stability + flavor.

Heat accelerates denaturation; acid + heat = faster, firmer set.