Detection of soybean protein in surimi products by fluorescently-labeled monoclonal antibody

The usage of soybean proteins in surimi products is increasing and becomes a new problem for aquatic products processing.Thus, establishment of an effective detection method for soybean proteins is essential.In the present study, soybean trypsin inhibitor (STI) was purified from soybean meal by a series of pretreatments, including acetone, H2SO4 treatments, ammonium sulfate fractionation and sequential column chromatographies.For monoclonal antibody (A11-6) preparation, purified STI was used to immunize mouse and the serum was purified by a Protein G Sepharose affinity column.Heherobifunctional reagent N-succinimidyl3-2-pyridyldithiopropionate (SPDP) and dithiothreitol (DTT) were used successfully to crosslink anti-STI monoclonal antibody with R-phycoerythrin (R-PE) .Western blot using this fluorescently-labeled antibody was then established and applied to analyze the existence of STI in surimi products.The limit of detection (LOD) of this method was 1.56μg/mL, which was slightly higher than traditional chemiluminescence method.This detection method is convenient, sensitive and safe in usage.