Omodara, N. B; Olabemiwo, O. M; Oyebade, A and Adekunbi, E. A.
Department of Chemistry, Adeyemi college of education, Ondo
Abstract: Analysis of fresh and smoked mud fish sold and consumed generally in the western part of Nigeria were purchased in Ondo and smoked at different time intervals for 1hr, 2hr, 3hr and 4hr at a temperature range of 200 oC – 210 oC with the use of firewood and charcoal. About 10 g of sample was taken from the homogenized sample and extracted with ultrasonicator using methanol, methanol : dichloromethane (1 : 1 v/v) and dichloromethane. The extracts were separated by column chromatography using n-hexane, n-hexane: dichloromethane (2 : 3). The aromatic fractions were subsequently analyzed with Gas Chromatography (GC/FID). The result showed that 24 PAHs were detected in all the samples except in FSMF 1hr and CSMF 1hr – 4hr where benzo (j)fluoranthene was below detection limit. The total PAHs concentrations in all the processed samples were higher than the unprocessed sample and the CSMF PAHs were significantly higher than FSMF PAHs. The phenanthrene/anthracene ratio for FSMF ranged from 0.2650 – 9.0146 and 0.7181 – 1.6545 for CSMF which suggests the source of the PAHs was pyrolitic. Also, Fluoranthene/fluoranthene + pyrene ratio ranged from 0.00297 – 0.5408 in FSMF and 0.00704 – 0.9859 for CSMF samples which equally suggest a pyrolytic source. From the proximate analysis results, the crude protein for the UPMF was 28.266 which increasesd gradually to 47.7 % in FSMF 4hr and increased to 65.94 % in CSMF 4hr. The crude fiber of all the samples both processed and unprocessed were generally low than expected. The percentage composition of fat was 1.01 % unprocessed to 6.04 % CSMF 4hr.
Keywords : GC/FID, smoked, extract, ultrasonication, processed