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Benzo[a]pyrene (BaP) was dissolved in glyceryl trioctanoate, heated in a glass reaction vessel within temperature range 297.95–361.85 K with heating rate of 1 K/min and simultaneously exposed to UV light at wavelength λ = 365 nm at radiation power 20 mW cm−2 in order to study the decrease of BaP concentration due to its photooxidation. The concentration of BaP was determined by HPLC-FD periodically in 5 min intervals. As observed, the BaP concentration decreased from 62.2 μg L-1 to 19.8 μg L-1. From the experimental results, the parameters characterizing the non-isothermal kinetics of BaP photooxidation have been obtained. The parameters were tested at two various isothermal conditions (290.16 and 323.26 K) to verify a suitability of derived parameters. Comparing calculated and measured data of half-lives of BaP decrease at mentioned temperatures it was found that calculated half-lives are in a good accordance with those experimentally obtained values, when relative standard deviations at 290.16 K were 17.0% and 5.4% at 323.26 K, respectively. The kinetic parameters enable the calculation of the rate constant for any temperature in isothermal regime and make possible to model, in general, the kinetics of such processes without a deeper insight into their mechanisms. [ABSTRACT FROM PUBLISHER]

A new rapid, one-step semi-quantitative HPLC-MS method applicable for the separation and characterization of the group of total 10 BaP hydroxyderivatives (1-hydroxy benzo[a]pyrene, 2-hydroxybenzo[a]pyrene, 3-hydroxybenzo[a]pyrene, 4-hydroxybenzo [a]pyrene, 7-hydroxybenzo[a]pyrene, 8-hydroxybenzo[a]pyrene, 9-hydroxybenzo[a]py rene, 10-hydroxybenzo[a]pyrene, 12-hydroxybenzo[a]pyrene and benzo[a]pyrene-9,10-dihydrodiol) was developed, involving electrospray ionization technique (ESI) in positive mode. Its qualitative and quantitative characteristics were selected by the analysis of the model OH-BaP mixture consisted of compounds mentioned above. The model system offered the linear response in the whole concentration range used (50–1000 ng.mL−1) as well as the resolution sufficient for semi-quantitative purposes (RS > 0.5). Subsequently, the suitability of the developed method was tested on BaP decomposition products to be formed during photooxidation at λ = 365 nm. These analyses confirmed the applicability of the proposed method, succeeding in the identification of 5 BaP hydroxyderivatives formed upon the BaP photooxidation experiment. [ABSTRACT FROM PUBLISHER]

Decomposition of benzo[a]pyrene (BaP) was studied at two different light wavelengths, i.e. 254 nm and 365 nm in a non-polar medium (n-hexane) at concentrations 50, 100 and 150 µg⋅l-1. At chosen time intervals, BaP concentration was measured by HPLC using fluorescence detection. Comparing rate constants k and half-lives τ½ it was found that decomposition at 365 nm was 15.3 times faster in comparison with the decomposition at 254 nm. The decompositions obey the first order kinetics. Considerable effect had addition of food antioxidants, 2,6-di-tert-butyl-4-methylphenol (BHT) and o-methoxyphenol (guaiacol), which both accelerated the rate of BaP decomposition -- BHT by 1.17 times and guaia col even 1.45 times. This means that both antioxidants had pro-oxidant effects on BaP. These findings may represent a basis for a new approach to decrease PAH content in foods, where their presence is due to the applied production technology. [ABSTRACT FROM AUTHOR]

Possibly harmful compounds (acrylamide, 5-(hydroxymethyl)-2-furfural -- HMF), markers of the Maillard reaction extent (furosine, fluorescence, browning, colour), as well as beneficial radical-scavenging capacity were determined in fried fine bakery products, rosquillas, at different heat treatment and dough formulation. In different simplified recipes, saccharose was substituted by glucose and fructose, and a raising agent was added while different temperature and time regimes were applied. Duration of frying from 4 min to 8 min increased the acrylamide content from (43 ± 8) µg⋅kg-1 to (159 ± 12) µg⋅kg-1 at 180 °C, and from (94 ± 3) µg⋅kg-1 to (366 ± 5) µg⋅kg-1 at 200 °C. Sodium hydrogen carbonate addition resulted in an only weak (13%) decrease in the acrylamide content, but in a more pronounced (80%) suppression of HMF formation. Substitution of saccharose for the mixture of glucose and fructose caused a decrease in acrylamide contents instead of its expected increase, but HMF formation was strongly supported by the presence of fructose. On the other hand, beneficial properties, such as radical-scavenging capacity, browning, colour, and fluorescence parameters were developing with the advance of Maillard reaction. Colour parameters were in good correlation with radical-scavenging capacities of final products prepared from saccharose (correlation coefficients, 0.779-0.981) as well as with acrylamide contents in samples made under all recipe modifications (correlation coefficients, 0.882-0.979). [ABSTRACT FROM AUTHOR]

Benzo[a]pyrene (BaP) was dissolved in glyceryl trioctanoate, heated in a glass reaction vessel within a temperature range of 303.15-473.15 K at the heating rates 0.1, 0.2, 0.5, 1 and 2 K⋅min-1, respectively, and simultaneously exposed to UV light at the wavelength λ = 365 nm at the radiation power of 20 mW⋅cm-2 in order to study the decrease of BaP concentration due to its photooxidation. The reaction mixture was sampled at temperature increments of 10 K and the concentration of BaP was determined by HPLC with fluorescence detector. As observed, the BaP concentration decreased from initial 100 µg⋅l-1 in dependence on the heating rate. From the experimental results, the kinetic parameters of the first-order kinetic equation (A = (2.8 ± 5.9) x 10-14 min-1, D = (5.86 ± 0.43) x 10-2 K-1) describing the kinetics of BaP photooxidation were obtained. Knowing the kinetic parameters, modelling of the photooxidation for any time/temperature regime is feasible without a deeper insight into the mechanism of the process. The advantage of the multiple heating rate approach lies in the fact that a larger part of the kinetic hypersurface is mapped so that the kinetic parameters obtained are more reliable and trustworthy as when obtaining the kinetic parameters just from a single kinetic curve. [ABSTRACT FROM AUTHOR]