A fast and cost-effective procedure for reliable measurement of trypsin inhibitor activity in soy and soy products

Rapid and accurate measurement of trypsin inhibitor is critical for soy processors to assess the quality of soy meal. Currently, trypsin inhibitor activity is measured using the American Oil Chemists' Society (AOCS) and the American Association of Cereal Chemists International (AACCI) approved method. We have modified and improved the AACCI/AOCS approved method resulting in the elimination of several time-consuming steps and drastically reducing the assay volume. By employing our simplified procedure, we have measured trypsin inhibitor activity of several soy and soy products. A side-by side comparison of our simplified procedure with AOCS approved method revealed strikingly similar results indicating that several time-consuming and tedious steps associated with AACCI/AOCS approved methods can be eliminated without sacrificing the accuracy of the assay. Moreover, we demonstrate that our assay can also be carried out in 96-well microplates which will enable high-throughput screening of large number of soy meal samples.