Food allergies of type-I-
allergy are
immunoglobulin E (
IgE) mediated and caused by certain
proteins or
glycoproteins, which are called food
allergens. An analytical marker of
allergens is the
IgE-reactivity to these substances. Normally food
allergens are minor components in allergenic source material, which consist of a huge number of chemical different substances. Thus
allergen extraction, separation and immunological detection methods are described which identify and characterize individual food
allergens by a minimum of manipulation. Favoured separation methods of allergenic extracts are electrophoretic ones allowing the combination of highly resolved
protein separations with immunological detection methods subsumed by the term immunoblotting. These techniques are a useful basis to characterize
allergens by chemical methods. Once the primary protein structure of a food
allergen is established, the way is cleared for the identification of
epitopes.
Epitopes are immunological detectable parts of a
protein or
glycoprotein generating the interface between chemical structure and immune-system. The nature of
epitopes may differ, for instance, can be conformational, continuous, or built up by
glycoconjugates, which determine the stability of food
allergens, especially in the case of food processing. Progress in identification and characterization of food
allergens will improve diagnostics and
therapy of
food allergy.