Cereals: a source of allergenic proteins and their characterization by proteomics

Cereals are sources of essential carbohydrates, nutrients and proteins. The most consumed cereals are wheat, rice and maize. However, cereals cause various allergic reactions which are associated with presence of gluten-based and non-gluten-based allergenic proteins. In addition to traditional methods used for detection of allergenic proteins such as ELISA, Western blotting and 2D immunoblotting, mass spectrometry (MS)-based proteomic approaches are applied for identification of cereal proteomes and to distinguish among highly similar peptide sequences of cereal gluten proteins. Using MS-based proteomics, identification/quantitation of allergenic proteins and discovery of novel epitopes responsible for allergic reactions are possible with high accuracy. This allows for development of precise diagnostic tools and therapy. In this review, the proteins of wheat, barley, rye, rice and maize are described with main focus on their association with IgE-mediated allergy. The methods for cereal protein characterization are discussed and examples of proteomic studies on cereal allergenicity are included.