Detection and stability of the major almond allergen in foods

Almond major protein (AMP or amandin), the primary storage protein in almon ds, is the major allergen recognized by almond-allergic patients. A rabbit antibody-based inhibition ELISA assay for detecting and quantifying AMP in commercial foods has been developed, and this assay, in conjunction with We stern blotting analyses, has been applied to the investigation of the antig enic stability of AMP to harsh food-processing conditions. The ELISA assay detects purified AMP at levels as low as 87 +/- 16 ng/mL and can detect alm ond at between 5 and 37 ppm in the tested foods. The assay was used to quan tify AMP in aqueous extracts of various foods that were defatted and spiked with known amounts of purified AMP or almond flour. In addition, AMP was q uantified in commercially prepared and processed almond-containing foods. N either blanching, roasting, nor autoclaving of almonds markedly decreased t he detectability of AMP in subsequent aqueous extracts of almonds. Western blots using both rabbit antisera and sera from human almond-allergic patien ts confirm a general stability of the various peptides that comprise this c omplex molecule and show that the rabbit antibody-based assay recognizes su bstantially the same set of peptides as does the IgE in sera from almond-al lergic patients.