Sistematic study of benzo[a]pyrene in coffee samples

Abstract

A method for extracting and quantifying benzo[a]pyrene (B[a]P) was evaluated and improved for samples of green and roasted ground Arabica (Coffea arabica) and Conillon (Coffea canephora) Brazilian coffees. The influence of the roasting process in B[a]P formation was considered too. These samples were extracted with acetone, followed by saponification and cyclohexane extraction. The extracts were cleaned by chromatography on a silica-gel. The quantification was done by HPLC with reversed-phase and fluorescence detection under isocratic conditions. The detection and quantification limits were 0.03 μg kg-1 and 0.10 μg kg-1, respectively. The recovery ranged from 76 to 116% for concentrations between 1.00 and 3.00 μg kg-1. The values obtained for B[a]P concentrations were from 0.47 to 12.5 μg kg-1 for samples of ground roasted coffee. B[a]P was absent in the green coffee samples. The control of the roasting parameters is fundamental for obtaining a good quality product.