Transformation of 3,5-dimethoxy-4-hydroxy cinnamic acid (sinapic acid), sinapaldehyde, sinapine and sinapoyl in the model system containing an enzyme secreted by the fungus Trametes versicolor was investigated. The affinity of this enzyme was highest for sinapic acid followed by sinapaldehyde and sinapine. The optimum temperature and pH for these transformations were 50 degrees C and pH 3.3, 50 degrees C and pH 4.5, 60 degrees C and pH 4.0 for sinapaldehyde, sinapine, and sinapic acid, respectively. The apparent heat of the enzyme-sinapic acid complex formation is -2557.6 J mol(-1). Higher concentrations of sinapine and sinapic acid caused enzyme inhibition. When canola meal was treated with this enzyme the phenolics content in this commodity was decreased by 90%.