title: Prediction of the hydrophilic antioxidant capacity of tomato pastes from the IR and fluorescence excitation-emission spectra of extracts and intact samples.
abstract: The performance of the recently proposed excitation-emission fluorescence method was compared to the method using infrared measurements for the evaluation of the antioxidant properties of intact samples and extracts that had been obtained from tomato pastes. The oxygen radical absorbance capacity assay (ORAC) was applied in order to estimate the antioxidant capacity of the extracts, while the Folin-Ciocalteu reagent was adopted for the evaluation of the total phenolic content. The optimal extraction conditions for tomato pastes (three minutes of sonication under 80°C) were determined using the central composite design. Chemometric models such as the partial least squares regression and its N-way variant were further constructed in order to predict the antioxidant capacity or total phenolic content of the samples using either the IR or fluorescence spectra. The prediction errors that were obtained for the total antioxidant content were evaluated as the Trolox equivalents from the ORAC assay and were found to be equal to 2.011 (14.21%) for the fluorescence and 2.426 (17.15%) for the IR spectra, respectively. The prediction errors of the total phenolic content expressed as gallic acid equivalents were 0.067 (10.78%) for the fluorescence and 0.033 (5.36%) for the IR spectra, which were used as independent variables in the regression models.
authors: Institute of Chemistry, University of Silesia, 9 Szkolna Street, 40-006 Katowice, Poland.
authors: Joanna
authors: J
authors: Orzel
authors: Institute of Chemistry, University of Silesia, 9 Szkolna Street, 40-006 Katowice, Poland.
authors: Ivana
authors: I
authors: Stanimirova
authors: Faculty of Chemistry, University of Wroclaw, 14 Joliot Curie Street, 50-383 Wroclaw, Poland.
authors: Boguslawa
authors: B
authors: Czarnik-Matusewicz
authors: Institute of Chemistry, University of Silesia, 9 Szkolna Street, 40-006 Katowice, Poland. Electronic address: mdaszyk@us.edu.pl.
authors: Michal
authors: M
authors: Daszykowski
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D057927:Hydrophobic and Hydrophilic Interactions; D018551:Solanum lycopersicum / Q000737:chemistry*; D010636:Phenols / Q000032:analysis*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013050:Spectrometry, Fluorescence / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
chemical_list: D000975:Antioxidants; D010636:Phenols; D017382:Reactive Oxygen Species
keywords: Fiber optics probe; IR-ATR; N-PLS; ORAC; PLS; TAC