TY - JOUR A1 - Mohsin, G. F. A1 - Schmitt, F.-J. A1 - Kanzler, C. A1 - Epping, J. D. A1 - Flemig, Sabine A1 - Hornemann, A. T1 - Structural characterization of melanoidin formed from D-glucose and L-alanine at different temperatures applying FTIR, NMR, EPR, and MALDI-ToF-MS JF - Food Chemistry N2 - The aim of this study was to identify specific chemical bonds and characteristic structures in melanoidins formed from D-glucose and L-alanine between 130 and 200 °C. The results might be used to control the type and amount of melanoidin produced during food processing. For this purpose, complementary techniques, such as FTIR, NMR, EPR, and MALDI-ToF, were employed. At 160 °C color, solubility and UV/Vis absorption change characteristically and consequently, structural transformations could be observed in FTIR and NMR spectra. For example, sharp signals of N-H, C-N, and C-H oscillations in the L-alanine spectrum are prone to inhomogeneous broadening in melanoidins prepared above 150 °C. These changes are caused due to formation of heterogeneous macromolecular structures and occur during condensation reactions that lead to an increasing loss of water from the melanoidins with increasing temperatures. Additionally, MALDI-ToF-MS indicates the polymerization of glyoxal/glyoxylic acid and EPR shows the formation of radical structures. KW - MALDI-ToF-MS KW - Melanoidine KW - Konjugate KW - Lebensmittel KW - MALDI-ToF-MS KW - L-alanine KW - D-glucose KW - Maillard reaction KW - FTIR spectroscopy KW - EPR spectroscopy KW - Melanoidin KW - NMR spectroscopy PY - 2018 DO - https://doi.org/10.1016/j.foodchem.2017.11.115 SN - 0308-8146 VL - 245 SP - 761 EP - 767 PB - Elsevier Science CY - Amsterdam, NL AN - OPUS4-44018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weigel, Sandra A1 - Wetekam, J. A1 - Mollenhauer, K. T1 - Identification and classification of PAH in asphalt binders with FTIR spectroscopy and multivariate analysis methods JF - Fuel N2 - Reclaimed asphalt pavements (RAP) with increased contents of polycyclic aromatic hydrocarbons (PAH) are restricted for reuse due to their harmful effects on humans and the environment. This work investigated whether Fourier transform infrared (FTIR) spectroscopy is suitable for a fast and simple identification and quantification of PAH in binders recovered from reclaimed asphalts. For this, the binders from 34 RAP samples were recovered using a rapid procedure developed at the Universität Kassel and were examined with infrared spectroscopy. The obtained spectra were pre-processed (Standard Normal Variate transformation, 1st derivative) and evaluated using a combination of factor analysis and linear discriminant analysis. The results showed that various PAH groups with differently pronounced aromatic structures are present in the binders. However, with FTIR spectroscopy combined with the multivariate methods, a statistical model was developed allowing for the differentiation between the PAH groups and also for the distinction between PAH contents below or above the threshold of 25 mg/kg valid in Germany. KW - Polycyclic aromatic hydrocarbons PAH KW - Reclaimed asphalt KW - Rapid procedure for binder extraction KW - FTIR spectroscopy KW - Multivariate analysis methods PY - 2023 DO - https://doi.org/10.1016/j.fuel.2022.126845 SN - 0016-2361 VL - 337 SP - 1 EP - 7 PB - Elsevier Ltd. AN - OPUS4-56961 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -