A perspective on pea allergy and pea allergens

Abstract

BackgroundPeas contain comparatively high levels of protein. With the recent trend for the development of alternative, high-protein food sources, pea flour, pea protein concentrate, and pea protein isolate have been incorporated into an increasing number of foods. Marketing materials sometimes claim that peas are hypoallergenic. Among the legume family, peanuts and soybeans are considered as commonly allergenic and regulations in many countries require special labeling and manufacturing control measures for foods containing peanuts or soybeans or ingredients derived from those two legumes. Peas are also legumes but are not on the lists of priority allergenic foods, so special labeling and manufacturing control measures are not needed for peas or pea-based ingredients. The increasing use of high-protein, pea-based ingredients in processed foods may necessitate further review of the placement of peas on the lists of priority allergenic foods. Additionally, peas are definitely allergenic and should not be marketed as hypoallergenic. Scope and approachThe clinical allergy literature was searched for publications describing allergic reactions to peas, including both garden peas and field peas. The identification and characteristics of pea proteins are reviewed. The potential cross-reactivity of pea proteins with known allergens from peanut and soybean is assessed using a bioinformatics comparison. Key findings and conclusionsAllergies to both garden peas and field peas are well documented. As consumer exposure to pea protein increases, an increase in allergies to peas should also be anticipated. Several allergenic proteins have been identified among the pea protein fractions. Pis s 1, a vicilin in the globulin fraction, appears to be the immunodominant allergen but additional studies on pea allergens are warranted. Pis s 2, a convicilin from the globulin fraction, is also identified as a pea allergen. The albumin fraction contains the two less well characterized allergenic albumin protein(s) known as PA1 and PA2. Furthermore, a non-specific lipid transfer protein (nsLTP), a member of the pathogenesis-related protein family (PR14) involved in plant defenses has been identified as an allergen. Strikingly, pea seeds do not contain the classical type of 2S albumin proteins, with the conserved Cys motif, of high allergenic potency found in peanut (such as Ara h 2, 6, and 7), soybean (Gly m 8), and certain tree nuts, e.g. Ber e 1 in Brazil nut, Ana o 3 in cashew, and Jug r 1 in walnut. The effects of processing on the allergenicity of peas have not been thoroughly evaluated, although some evidence indicates that the allergenicity of peas can be reduced by blanching for at least some pea-allergic individuals and that the pea albumin allergens have some limited heat stability.