Polycyclic Aromatic Hydrocarbons formed during Roasting Process in Arabica Coffee Beans

Abstract

Roasting is a critical process in coffee production, as it enables the development of flavor, colour and aroma, and may lead to the formation of non-desirable compounds, such as polycyclic aromatic hydrocarbons (PAHs). Among the number of PAHs, sixteen of them have been classified as priority pollutants by United State Environmental Protection Agency (USEPA) are of special concern due to their carcinogenic and mutagenic properties. In this regard, Arabica coffee beans were roasted under controlled conditions to monitor the formation of PAH during the roasting process. Soxhlet extraction method was used for the extraction of PAHs. Five to eleven PAHs from list of 16 PAHs (USEPA) were found to be present. Concentrations of total PAHs in green and roasted coffee beans was found to be vary from 30.0-955.8 μg/kg. Benzo[a]pyrene (2A: probable human carcinogen) was not detected in any roasted coffee sample. However, 2-ring PAH viz., naphthalene (2B: possible human carcinogen) was found to convert into higher ring PAHs, as a result its concentration gradually decreases and becomes undetectable in coffee beans after 100oC of roasting temperature.