Effect of mild roasting on Arabica and Robusta coffee beans contamination with polycyclic aromatic hydrocarbons

Marta Ciecierska,Beata Drużyńska,Rafał Wołosiak,Ewa Majewska,Jolanta Kowalska,Dorota Derewiaka

doi:10.1007/s13197-018-3532-0

Marta Ciecierska, Beata Drużyńska + Show 4 more

Open Access

https://doi.org/10.1007/s13197-018-3532-0

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Abstract

The aim of this research was to establish the effect of mild roasting on coffee beans contamination level by polycyclic aromatic hydrocarbons (PAHs). The materials investigated were green Arabica and Robusta coffee beans imported from different countries, as well as those already roasted. The experiment was carried out in a coffee-roasting plant, with the use of an electric coffee roaster, at the temperature of 125–135 °C for 25–26 min. PAHs analysis was conducted by means of high-performance liquid chromatography with fluorescence and diode array detectors (HPLC-FLD/DAD). Results had been verified by means of gas chromatography with mass spectrometry. Contamination level for 19 PAHs, 15 of which were heavy PAHs included on the list of European Union Scientific Committee in Food, varied from 4.29 to 16.17 µg/kg in roasted coffee beans, whereas in green coffee beans varied from 8.66 to 76.63 µg/kg. The results of statistical analysis showed that the contamination level in roasted coffee beans was significantly lower than that in green beans. The applied parameters of roasting did not lead to the occurrence of conditions in which PAHs, especially heavy ones, would possibly be formed. On the contrary, the roasting process itself had significantly reduced the PAHs content in the final product. The reason for this phenomenon was relatively high volatility of light PAHs.

Highlights

Polycyclic aromatic hydrocarbons (PAHs) are toxic compounds of various structure existing commonly in the natural environment
The results obtained by HPLC-FLD/DAD method were confirmed with the use of gas chromatography with mass spectrometry (GC/MS) in accordance with the method described by Ciecierska and Obiedzinski (2013a)
In order to examine the effect of mild roasting on the coffee beans’ polycyclic aromatic hydrocarbons (PAHs) contamination, PAHs were determined in green Arabica and Robusta coffee beans and after roasting using an electric coffee roaster

Summary

Introduction

Polycyclic aromatic hydrocarbons (PAHs) are toxic compounds of various structure existing commonly in the natural environment. They originate from the incomplete combustion of organic matter. Heavy PAHs are considerably more toxic than light ones (EFSA 2008; Murkovic et al 2018; Singh et al 2016). As stated in the European Union Commission Recommendation from 4 February 2005, further scientific investigation of these PAHs content in foodstuffs is required (Commission of the European Communities 2005). In 2008 European Food Safety Authority (EFSA) stated that 4 heavy, specific marker PAHs (benzo[a]pyrene (B[a]P), benzo[a]anthracene (B[a]A), benzo[b]fluoranthene (B[b]F) and chrysene (Chr)) are the most suitable indicators of foodstuffs PAHs content, and their presence in food should be monitored. The same was stated in Commission Regulation (EU) No 835/2011 (Commission of the European Communities 2011a; EFSA 2008)

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