Plant food allergens: either protective or storage proteins
population. A European-funded project was set up to improve the
understanding of factors that may be important in predisposing
certain plant food proteins to becoming allergens. Read about their
revelations here.
Food allergies are a consequence of inappropriate immune responses to some food proteins resulting in a generation of antibodies (immunoglobulin E, or IgE). The main foods responsible for the majority of food allergies are peanuts and tree nuts, wheat, soya, cow's milk, egg, shellfish and fish. It has been estimated that 1-2 per cent of adults and 5-7 per cent of children actually have confirmed allergies to foods.
Flair-Flow 4, a network that disseminates food research results to consumer groups, health professionals and the food industry in 24 European countries, set up a project to improve the understanding of factors that may be important in predisposing certain plant food proteins to becoming allergens and reducing or removing allergenic determinants through processing.
Plant proteins may be divided into 3 sub-classes: structural and metabolic proteins; protective proteins (which defend a plant against invasion by pathogens or feeding by pests); and storage proteins (which act as a nutrient store to support germination in seeds).
According to a recent study update, it appears that almost all plant food allergens are either protective or storage proteins. It is also clear that those proteins that trigger the development of an allergic response through the gastrointestinal tract belong primarily to two large protein families: the cereal Prolamin Superfamily and the Cupin Superfamily. Proteins within each family are all similar in their molecular structure.
Other significant results from the study are the development of technologies to reduce or to remove the allergens, or the active sites (the epitopes), of the allergenic proteins. The work has concentrated on 3 technologies: removal of the epitopes (e.g. peeling of peaches removes a considerable part of allergenicity); their destruction (e.g. through heat treatments to unfold and deactivate them or through their hydrolysis by proteases); and their masking (e.g. by cross-linking the epitopes by transglutaminase or by other enzymatic reactions).
Further information about the project can be obtained from the project website or from a synthesis report that Flair-Flow will soon be publishing.
