Quantitative Determination of Trypsin Inhibitory Activity in Complex Matrices

Robin E.J. Spelbrink*, Pieter Jan Gerrits, Carina Mooij, Marco L.F. Giuseppin
AVEBE U.A., AVEBE-weg 1, 9607 PT, Foxhol, The Netherlands.

© 2014 Spelbrink et al;

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the AVEBE U.A., AVEBE-weg 1, 9607 PT, Foxhol, The Netherlands; Tel: +31 598 662 730; Fax: +31598664273; E-mail: Robin.Spelbrink@AVEBE.COM


A quantitative assay using azocasein was developed to measure trypsin inhibitory activity in emulsions and other complex systems that are refractory to analysis. The method was tested for reproducibility on pure protein solutions as well as protein-containing material rich in fats and sugars, with special attention to emulsions. In the clean situation, the overall relative standard deviation was less than 6% while for the more complex systems it was less than 16%. The procedure proved robust against deliberate variations of temperature, incubation time and substrate concentration.

Keywords: Azocasein, Emulsion, Trypsin, Protease Inhibitor, Potato Protease Inhibitor, Trypsin Inhibitory Activity.