Comparative Evaluation of Lycopene and Heavy Metal Contents Of Two Species of Tomatoes Within Awka Metropolis (Published)
Tomato Species belong to edible vegetable fruit obtained from tomato plant which serves as a food source to people irrespective of culture, religion and belief. Two species of the tomato samples were bought from five different local markets within Awka metropolis, Anambra State. The samples were washed with deionised water, and lycopene content extracted using solvent mixture of n-hexane, acetone and ethanol in the ratio of 2:1:1 respectively. The extract was subjected to Uv spectrophotometer for lycopene content at 503nm. The moisture content was examined via difference in weight in an oven at 1050c. The washed samples were blended and digested with acid mixture of 10ml perchloric acid, 25ml concentrated nitric acid and 4ml sulphuric acid. The level of heavy metal in the digest was evaluated using atomic absorption spectrophotometer. The results showed lycopene range of 18.82mg/kg to 98.52mg/kg. The higher concentration of lycopene was associated with Beefsteak species with average value of 73.13mg/kg, while a lower average level of 40.76mg/kg was implicated in cherry specie. Lead was the metal with lowest average concentration of 0.083ppm. The metal with the highest average concentration in the tomato samples was chromium (0.520ppm). The observed trend in the metal concentration for all the samples was Cr (0.520ppm) > Cu (0.493ppm) > Fe (0.453ppm) > Zn (0.421ppm) > Cd (0.121ppm) > Pb (0.083ppm). Only Pb was within the permissible limit as stipulated by WHO (Pb-0.1mg/L), all other metals were above the permission limit as stated by FAO and WHO of 2011. Expectedly the tomato had high moisture content (95.7%). Statistical treatment of the data showed the existence of a strong inverse correlation between Fe and Pb concentration in the tomato sample (r = -710, p = 0.020). There was no statistical correlation between lycopene content and the total metal concentration (r = -0.349, p = 0.324).
Keywords: Heavy Metal, Lycopene, Tomato, Vegetable, fruits and spectrophotometer