Quantitative Analysis of Total Carotenoids in Some Vegetables Consumed in Akwa Ibom State, Nigeria

Abstract

The quantitative analysis of total carotenoids in some vegetables consumed in Akwa Ibom State was evaluated using UV-Spectrophotometer and acetone as extraction solvent. Ten different vegetable samples i.e. Carrot (Daucus carota),purpleegg plant(Solanum melongena), green egg plant (Solanum melongena), tomato(Solanum lycopersicum), cucumber(Cucummis sativa),fluted pumpkin (Telfairia occidentalis), spinach(Spinacia oleracea), red pepper(Capsicum annuum, green pepper(Capsicum annuum)and bitterleaf (Vernonia amygdalina)were purchased from local markets in Itam and Ikot Akpaden, both in Akwa Ibom State. The fresh samples were washed with tap water, followed by distilled water. The samples were homogenized separately using sterile mortar and pestle with 10 ml acetone as extraction solvent. The extract was centrifuged at 10,000rpm for 15 mins in 4°C and the supernatant analysed as soon as possible using spectrophotometer (UV-VIS 2500) at 470 nm. The quantification of carotenoids was carried out according to Harbone J B, 1973 andon the basis of Beer Lambert’s equation: A=ƸCL in mol/l and converted to mg/ml. From the result obtained, Capsicum annuum (red pepper) had the highest amount of carotenoids (2.889 mg/ml), Solanum lycopersicum showed the lowest amount of carotenoid (0.260 mg/ml) the deep green vegetables also had high quantity of carotenoids. Carotenoids are important due to the health benefits associated with the pigment acting as provitamin A, a strong antioxidant and gives colouration to plants. It also helps in preventing photo-damage in plants and has some health benefits like improving sight, reducing cancer risk to animals too. Further studies analyzing the individual carotenoids is recommended and investigation on the effect of time on extraction.