Comparison of PAHs Formed in Firewood and Charcoal Smoked Stock and Cat Fish

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are a product of incomplete combustions. Foods prepared via combustion and high temperature are linked with incomplete combustion making them vulnerable to having PAHs in their constituent. Two species of fish: stock fish and cat fish were bought from Ogbomoso and smoked using firewood and charcoal at various time intervals. The processed samples were extracted using ultrasonicator and the extracts separated using n-hexane, mixture of dichloromethane and n-hexane (3:2). The identification and concentration of PAHs were carried out using Gas chromatography coupled with flame ionization detector (GC/FID) while the proximate analysis was done according to the standard described by AOAC, 2002. The GC/FID analysis showed that 24 PAHs were found in all the samples except Naphthalene and benzo (j) fluoranthene which were not detected in firewood smoked stock fish and charcoal smoked cat fish respectively at various smoking time. The total concentration of PAHs in firewood smoked stock fish (FSSF) ranged from 7.36 – 16.84 mg/kg, total concentration in charcoal smoked stock fish (CSSF) ranged from 1352.23 – 1736.06 mg/kg while the total concentration in firewood smoked cat fish (FSCF) ranged from 91.22 – 1248.77 mg/kg and PAHs concentrations in charcoal smoked cat fish (CSCF) ranged from 200.11 – 1847.44 mg/kg. The proximate analysis revealed that, the highest moisture content (63.25 %) in all the samples was obtained in FSCF 1h, highest protein content (65.94 %) obtained in CSSF 4h, highest fat (28.15 %) obtained in FSCF 4h. The molecular indices ratio suggested that the PAHs were from pyrolytic source.