The effects of roasting on the allergenic properties of peanut proteins

Background: Because of the widespread use of peanut products, peanut allerg enicity is a major health concern in the United States. The effect or effec ts of thermal processing (roasting) on the allergenic properties of peanut proteins have rarely been addressed, Objective: We sought to assess the biochemical effects of roasting on the a llergenic properties of peanut proteins. Methods: Competitive inhibition ELISA was used to compare the IgE-binding p roperties of roasted and raw peanut extracts. A well-characterized in vitro model was used to test whether the Maillard reaction contributes to the al lergenic properties of peanut proteins. The allergic properties were measur ed by using ELISA, digestion by gastric secretions, and stability of the pr oteins to heat and degradation, Results: Here we report that roasted peanuts from two different sources bou nd IgE from patients with peanut allergy at approximately 90-fold higher le vels than the raw peanuts from the same peanut cultivars. The purified majo r allergens Ara h 1 and Ara h 2 were subjected to the Maillard reaction in vitro and compared with corresponding unreacted samples for allergenic prop erties. Ara h 1 and Ara h 2 bound higher levels of IgE and were more resist ant to heat and digestion by gastrointestinal enzymes once they had undergo ne the Maillard reaction. Conclusions: The data presented here indicate that thermal processing may p lay an important role in enhancing the allergenic properties of peanuts and that the protein modifications made by the Maillard reaction contribute to this effect.