Characterizing The Effect Of Sodium Sulfite On Cashew Allergens

Abstract

RationaleSulfites are multipurpose compounds included in the FDAs Generally Recognized as Safe (GRAS) list, but they can cause serious immunologic reactions in some individuals.They are commonly used as preservatives, to prevent enzymatic and non-enzymatic browning, and are found naturally in some foods. Our objective was to characterize the effect of sulfite compounds on cashew allergens.MethodsCashew extracts and purified cashew allergens were treated with sodium sulfite at various concentrations and temperatures and analyzed by SDS-PAGE. LC-MS/MS analysis identified sites of sulfite modification on cashew allergens, and cashew allergen structure was characterized by circular dichroism. IgE binding with cashew allergic patient sera was evaluated by immunoblot and ELISA.ResultsTreatment of cashew extracts with sodium sulfite at concentrations as low as 1 mM (126 ppm) altered migration of Ana o 2 and Ana o 3 on SDS-PAGE. LC-MS/MS and circular dichroism studies indicate that sodium sulfite targets the disulfide bonds of Ana o 3 disrupting its structure. Sodium sulfite treatment of cashew extracts reduced IgE binding to the Ana o 2 and Ana o 3 cashew allergens.ConclusionsTreatment of cashew extracts with sodium sulfite disrupts the structure of Ana o 2 and Ana o 3 allergens and reduces IgE binding. It is possible that sulfite treatment may diminish the allergenicity of cashew nuts. The potential creation of sulfite-dependent neo-antigens is unknown. Continued research is warranted to evaluate the inclusion of sodium sulfite or other sulfite compounds in cashew processing steps. RationaleSulfites are multipurpose compounds included in the FDAs Generally Recognized as Safe (GRAS) list, but they can cause serious immunologic reactions in some individuals.They are commonly used as preservatives, to prevent enzymatic and non-enzymatic browning, and are found naturally in some foods. Our objective was to characterize the effect of sulfite compounds on cashew allergens. Sulfites are multipurpose compounds included in the FDAs Generally Recognized as Safe (GRAS) list, but they can cause serious immunologic reactions in some individuals.They are commonly used as preservatives, to prevent enzymatic and non-enzymatic browning, and are found naturally in some foods. Our objective was to characterize the effect of sulfite compounds on cashew allergens. MethodsCashew extracts and purified cashew allergens were treated with sodium sulfite at various concentrations and temperatures and analyzed by SDS-PAGE. LC-MS/MS analysis identified sites of sulfite modification on cashew allergens, and cashew allergen structure was characterized by circular dichroism. IgE binding with cashew allergic patient sera was evaluated by immunoblot and ELISA. Cashew extracts and purified cashew allergens were treated with sodium sulfite at various concentrations and temperatures and analyzed by SDS-PAGE. LC-MS/MS analysis identified sites of sulfite modification on cashew allergens, and cashew allergen structure was characterized by circular dichroism. IgE binding with cashew allergic patient sera was evaluated by immunoblot and ELISA. ResultsTreatment of cashew extracts with sodium sulfite at concentrations as low as 1 mM (126 ppm) altered migration of Ana o 2 and Ana o 3 on SDS-PAGE. LC-MS/MS and circular dichroism studies indicate that sodium sulfite targets the disulfide bonds of Ana o 3 disrupting its structure. Sodium sulfite treatment of cashew extracts reduced IgE binding to the Ana o 2 and Ana o 3 cashew allergens. Treatment of cashew extracts with sodium sulfite at concentrations as low as 1 mM (126 ppm) altered migration of Ana o 2 and Ana o 3 on SDS-PAGE. LC-MS/MS and circular dichroism studies indicate that sodium sulfite targets the disulfide bonds of Ana o 3 disrupting its structure. Sodium sulfite treatment of cashew extracts reduced IgE binding to the Ana o 2 and Ana o 3 cashew allergens. ConclusionsTreatment of cashew extracts with sodium sulfite disrupts the structure of Ana o 2 and Ana o 3 allergens and reduces IgE binding. It is possible that sulfite treatment may diminish the allergenicity of cashew nuts. The potential creation of sulfite-dependent neo-antigens is unknown. Continued research is warranted to evaluate the inclusion of sodium sulfite or other sulfite compounds in cashew processing steps. Treatment of cashew extracts with sodium sulfite disrupts the structure of Ana o 2 and Ana o 3 allergens and reduces IgE binding. It is possible that sulfite treatment may diminish the allergenicity of cashew nuts. The potential creation of sulfite-dependent neo-antigens is unknown. Continued research is warranted to evaluate the inclusion of sodium sulfite or other sulfite compounds in cashew processing steps.