Effects of toasting procedures on the levels of polycyclic aromatic hydrocarbons in toasted bread

Ledicia Rey-Salgueiro; Mercedes Sonia García-Falcón; Elena Martínez-Carballo; Jesús Simal-Gándara

doi:10.1016/j.foodchem.2007.11.026

Effects of toasting procedures on the levels of polycyclic aromatic hydrocarbons in toasted bread

Food Chem. 2008 May 15;108(2):607-15. doi: 10.1016/j.foodchem.2007.11.026. Epub 2007 Nov 22.

Authors

Ledicia Rey-Salgueiro¹, Mercedes Sonia García-Falcón¹, Elena Martínez-Carballo¹, Jesús Simal-Gándara²

Affiliations

¹ Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E32400 Ourense, Spain.
² Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E32400 Ourense, Spain. Electronic address: jsimal@uvigo.es.

PMID: 26059139
DOI: 10.1016/j.foodchem.2007.11.026

Abstract

Some polycyclic aromatic hydrocarbons (PAHs), particularly those with a high molecular weight, have been classified as probably carcinogens to humans by the International Agency for Research on Cancer (IARC). The significance of the determination of PAHs is reflected by the special attention of the European Union, which is paying to regulate the maximum allowed levels of PAHs in foodstuffs such as smoked foods. Like other thermally processed foodstuffs, toasted bread can contain these carcinogenic chemicals, not only due to a contamination at source but also during toasting. In order to check PAHs generated from toasting in sandwich bread, several treatment conditions were evaluated: direct toasting (flame-toasting, coal-grilling or gas oven-toasting) or indirect toasting (electric oven-toasting). PAHs were extracted by solid-liquid extraction (SLE) and determined by liquid chromatography with fluorescence detection (LC-FD). Based on the results, the used toasted technique would strongly affect in PAH levels in the final product. No samples obtained by electric oven and toaster were polluted; otherwise the samples toasted by charcoal and flame grilling presented very important levels. Up to 350μg/kg of total PAHs were detected in toasted samples by wood flame. Differences between different ways of toasting could be ascribed to deposition of PAHs from smoke. Finally, several commercial toasted samples of bread were tested to determine PAHs. Overall, the PAH levels were very low. Benzo[a]pyrene ranged from no detectable to 0.23μg/kg.

Keywords: Activated carbon; Fluorescence spectrophotometry; Indirect and direct toasting; Liquid chromatography; PAHs; Toasted bread.