Fast profiling of food by analytical pyrolysis

The presence of carbon nanostructures in bakery products induces metabolic stress in human mesenchymal stem cells through CYP1A and p53 gene expression

Ingredients commonly present in processed foods are excellent substrates for chemical reactions during modern thermal cooking or processing, which could possibly result in deteriorative carbonization changes mediated by a variety of thermal reactions. Spontaneous self-assembling complexation or polymerization of partially combusted lipids, proteins, and other food macromolecules with synthetic food additives during high temperature food processing or baking (200-250 °C) would result in the formation of carbon nanostructures (CNs). These unknown nanostructures may produce adverse physiological effects or potential health risks. The present work aimed to identify and characterize the nanostructures from the crusts of bread. Furthermore, a toxicological risk assessment of these nanostructures was conducted using human mesenchymal stem cells (hMSCs) as a model for cellular uptake and metabolic oxidative stress, with special reference to induced adipogenesis. CNs isolated from bread crusts were characterized using transmission electron microscopy. The in vitro risk assessment of the CNs was carried out in hMSCs using an MTT assay, cell morphological assessment, a reactive oxygen species assay, a mitochondrial trans-membrane potential assay, cell cycle progression assessment and gene expression analysis. Our results revealed that bread crusts contain CNs, which may form during the bread-making process. The in vitro results indicate that carbon nanostructures have moderately toxic effects in the hMSCs at a high dose (400 μg/mL). The mitochondrial trans-membrane potentials and intracellular ROS levels of the hMSCs were altered at this dose. The levels of the mRNA transcripts of metabolic stress-responsive genes such as CAT, GSR, GSTA4, CYP1A and p53 were significantly altered in response to CNs.

Metabolism of 1-(4-hydroxy-3-methoxyphenyl)-2-propanone, a smoke flavour ketone, in rat

1. Metabolites of 1-(4-hydroxy-3-methoxyphenyl)-2-propanone (HMP-one), a smoke flavour compound, were isolated from rat urine using hydrolysis, ether extraction, t.l.c. and g.l.c. 2. Three metabolites were identified by mass spectrometry and independent synthesis, namely: 1-(3, 4-dihydroxyphenyl)-2-propanone (Met I), 1-(3, 4-dihydroxyphenyl)-2-propanol (Met II), and 1-(4-hydroxy-3-methoxyphenyl)-2-propanol (Met III). 3. A g.l.c. method for the quantitative determination of the parent compound and metabolites in urine was devised. Unchanged HMP-one accounted for about 74% dose, with Met I 11%, Met II 5%, and Met III 9%. All compounds were excreted both as sulphate and glucuronide conjugates.