Effects of Roasting on the Proximate Composition and Levels of Polycyclic Aromatic Hydrocarbons in Some Roasted Nigerian Delicacies

Department of Chemistry, University of Lagos, Akoka-Lagos, Nigeria. Department of Pharmaceutics and Pharm. Tech., University of Lagos, Nigeria. Corresponding Author: T.O. Oluseyi ___________________________________________________________________________ Abstract Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic pollutants which get into foods during processing. In spite of this, only a few studies have been carried out on Nigerian delicacies. Raw and roasted food samples of corn (Zea mays), ripe plantain, unripe plantain (Musa paradisiaca) and yam (Dioscorea sagittifolia) of southwest Nigeria were evaluated for nutritional (proximate analysis and macro nutrients) and anti-nutritional qualities PAHs. The starchy food samples consist mainly of carbohydrate ranging from 35.93 – 55.52%, percentage crude fibre, protein, crude fat and ash content ranged between 0.82 – 14.21%, 3.15 – 8.27%, 1.12 – 19.56% and 1.12 – 2.59% respectively. The gross energy content of the food samples ranged from 777 – 1678 KJ/100g. The concentrations of minerals (macro nutrients) were as follows: Copper (7.05–20.60 ppm), Iron (3.15-28.3 ppm), Magnesium (1.15–4.95 ppm), Manganese (0.70–3.80 ppm) and Zinc (1.05–9.60 ppm). Higher levels of PAHs were found in the roasted samples than the raw samples. The values of total PAHs for raw food samples ranged from 0.19 0.53 ppm with unripe plantain having the least concentration. For roasted food samples the total PAHs concentration ranged from 3.62 – 40.33 ppm, with ripe plantain having the highest concentration. There was no significant difference between the proximate composition of raw and roasted food samples (P<0.05, t-test). These results from this data can be used to determine any potential risk associated with the ingestion of these foods. __________________________________________________________________________________________