Improved extraction of peanut residues from a wheat flour matrix for immunochemical detection

The efficacy of different buffers in extracting peanut from a solid model food incurred with peanut and subjected to processing was evaluated using two commercial ELISA kits: Veratox® for peanut allergen and peanut ELISA from Morinaga. Average percentage recoveries of peanut from unprocessed samples using the kit supplied buffers were 46 ± 5 and 28 ± 2 with the Veratox and Morinaga kits, respectively. However, Na₂CO₃, pH 9.6 and PBS containing 1 M GuHCl recovered 65% ± 4% and 77% ± 10% of peanut, respectively from unprocessed samples with the Veratox kit. These two buffers also performed better than the Veratox buffer with fried, high pressure processed, and baked samples. PBS containing SDS and β-ME, performed significantly better than the Morinaga buffer in recovering peanut from unprocessed, boiled and fried samples. Thus, the use of alternative extraction buffers provides better recovery of peanut residues from a processed solid food matrix.