Antigenicity

The capacity of a substance to act as an antigen — provoking an antibody-mediated or cellular immune response. In food allergy, the antigenicity of proteins from peanut, milk, egg, soy or shellfish determines their power to sensitise and then trigger reactions. Processing changes it: heat can destroy conformational epitopes while creating new ones through Maillard chemistry, and hydrolysis generally reduces it. Regulators therefore require antigenicity assessment for novel foods, genetically modified crops and new protein ingredients, using sera from allergic patients and animal models to judge whether a new protein poses an allergy risk.