Multi-way chemometrics for mathematical separation of fluorescent colorants and colour precursors from spectrofluorimetry of beet sugar and beet sugar thick juice as validated by HPLC analysis

In previous analyses of colour impurities in processed sugar, a multi-way c hemometric model, CANDECOMP-PARAFAC (CP), has been used to model fluorescen ce excitation-emission landscapes of sugar samples. Four fluorescent compon ents were found, two of them tyrosine and tryptophan, correlating to import ant quality and process parameters. In this paper HPLC analyses are used to chemically verify and extend the CP models of sugar. Thick juice, an inter mediate in the sugar production, was analysed by size exclusion HPLC. Tyros ine and tryptophan were confirmed as constituents in thick juice. Colorants were found to be high molecular weight compounds. Fluorescence landscapes on collected column fractions were modelled by the CP model and seven fluor ophores were resolved. Apart from tyrosine and tryptophan, four of the fluo rophores were identified as high molecular weight compounds, three of them possible Maillard reaction polymers, whereas the seventh component resemble d a polyphenolic compound. It is concluded that the relevance of CP for mat hematical separation of fluorescence landscapes has been justified on two l evels by HPLC; firstly as a screening method of fluorophores in complex sam ples and secondly as a confirmation of peak purity in chromatographic separ ation. (C) 2000 Elsevier Science Ltd. All rights reserved.