Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/18/2007
Publication Date: 10/10/2007
Citation: Chung, S., Champagne, E.T. 2007. Effect of phytic acid on peanut allergens and allergenic properties of extracts. Journal of Agricultural and Food Chemistry. 55:9054-9058. Interpretive Summary: Phytic acid is a natural compound and a chief storage form of phosphate in oilseeds. At a certain concentration, phytic acid binds and makes minerals or proteins insoluble, and as a result, the human body cannot absorb these nutrients. Based on this concept, we hypothesized that adding phytic acid to a peanut extract would lead to the insolubilizing of peanut allergens and a reduction in the allergenic potency of the extract. To support our hypothesis we treated a peanut protein extract with phytic acid monocalcium salt, analyzed the change in levels of peanut allergens, and determined the allergenic potency of the extract using a pooled serum of peanut-allergic individuals. Data showed that the levels of soluble peanut allergens and the allergenic potency of the extract were reduced, following treatment with phytic acid. We concluded that phytic acid insolubilized peanut allergens and caused the extract to be less allergenic or hypoallergenic. Application of phytic acid to a peanut butter slurry presented a similar result, indicating that phytic acid may find use in the development of hypoallergenic peanut-based products.
Technical Abstract: Phytic acid is known to form insoluble complexes with most proteins. Our objective was to determine if phytic acid complexes with major peanut allergens, and results in a peanut extract with a lower level of soluble allergens and allergenic property. Extracts from raw and roasted peanuts were treated with phytic acid at various concentrations and pH for 10 min at 25 C, centrifuged, and then analyzed for allergen levels by SDS-PAGE. Allergenic property or IgE binding of treated extracts was determined in a competitive inhibition ELISA, using a pooled serum (IgE) from peanut allergic individuals. Results showed that phytic acid at a concentration of 2 mM and pH < 8 formed insoluble complexes with major peanut allergens, Ara h 1 and Ara h 2. Succinylation of the allergens inhibited complex formation, indicating that lysine residues were involved. IgE binding was lower in the phytic-treated extracts than in the untreated. We concluded that phytic acid reduced the levels of peanut major allergens, and allergenic properties of extracts by forming insoluble complexes with the allergens. Application of phytic acid to a peanut butter slurry presented a similar result, indicating that phytic acid may find use in the development of hypoallergenic peanut-based products.