Enzymatic browning of vegetables. Calibration and analysis of variance by multiway methods

This paper describes the chemometrical aspects of an investigation of the enzymatic browning of vegetables. Enzymatic browning is caused by polyphenol oxidase, PPO. Kinetic UV/VIS spectra and experimental design variables of PPO incubated samples are used for predicting enzymatic activity and substrate consumption. The mathematical models used are multiway PLS (N-PLS) and fiveway PARAFAC, Both methods are available from Internet in MATLAB code. Throughout the results of the multiway methods are compared to competing methods (PLS, PCR, Tucker, feedforward neural networks, locally weighted regression, ANOVA and others). The result of the investigation is, that the multiway methods have clear advantages with respect to predictions and interpretability, both mathematically and technologically.