Quantification of Lycopene from Tomatoes and Watermelons by Using Beer-Lambert Principle

Red tomatoes and red-fleshed watermelons contain a high level of lycopene.  It is well known that lycopene is precursor to vitamin A. In Uganda, and East Africa in general, there are so many tomato and watermelon varieties with little information on their lycopene content. However, no study has been done to estimate the quantity of lycopene in fresh tomatoes and watermelons in Uganda. The objective of this study was to quantify lycopene by using Beer-Lambert Principle. The varieties were bought from Nakulabye market in Kampala, and extracted by using solvent system of acetone/ethanol/ hexane (5ml/5ml/10ml). Stirring on ice was done for 15 minutes. 3 ml of deionized water was added after shaking. Samples were shaken for 5 minutes on ice and then left at room temperature for 5 minutes to allow the separation of phases. The lycopene layer were then separated and scanned in UV-VIS spectrophotometer. The results showed that the lycopene concentration ranged from 27 μg/g to 115 μg/g with % relative error ranged from 2.86 to 3.14, the standard error ranged from ± 0.013to ± 0.015,and standard deviation ranged from 7.38 to 29.5.  Both watermelons and tomato varieties contain the appreciable quantities of lycopene which is the significant nutrient for human body in daily life.

Effects Of Vegetable Drying Techniques On Nutrient Content: A Case Study Of South-Western Uganda

Micronutrient deficiencies are high in Uganda. To the rural poor, the most compelling and long- term strategy to address this problem is dietary diversity. However, post­harvest losses and seasonal variability within key foods still hamper the community­ based efforts to supply local food sources throughout the year. Vegetables are important in most of the daily diets and can be used to alleviate most of the micronutrient deficiencies. Vegetables are only available during the rainy season in rural areas. Therefore, it is necessary to preserve them and use them during the dry season when they are scarce. The objective of this study was to establish food preservation methods that could easily be adopted for preservation of vegetables in order to even out the imbalance of supplies between the rainy and the dry season. In order to achieve the objective, first, a survey was carried out in South Western Uganda, to identify the traditional methods of preservation of food plants. Then, the traditional methods were compared with other methods that can be used for drying vegetables, with respect to retention of nutrients after drying to determine the best method applicable to a rural setting. Sun drying was identified as the only traditional method of preserving foodstuffs in Rukungiri district. The method was cited by all households (n=116) in the drying of grains legumes and cereals such as maize, millet and sorghum. Apart from sun drying, two other methods are applicable to the rural setting; namely oven drying and solar drying. The effects of sun drying, solar drying and oven drying on the nutrient composition of selected vegetables were assessed by proximate analyses and compared with the nutrient content of the fresh vegetables. The results showed that some nutrients were lost during the drying process but in general, the nutrient content remained high. With respect to retention of the nutrient content in vegetables, solar drying was found to be the best of the three methods. Based on this study, solar drying is recommended as a method for vegetable preservation

PCDD/Fs and dioxin-like PCBs in fish species from Lake Victoria, East Africa.

Two commercially important fish species, Nile perch gates niloticus) and Nile tilapia (Oreochromis niloticus) belonging to different trophic levels were collected from the Napoleon Gulf and Thurston Bay in Lake Victoria. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxinlike polychlorinated biphenyls (dl-PCBs) were extracted from the fish muscles and livers using the C-13 isotope dilution method, followed by multiple column chromatography clean-up. Analysis was achieved by a high resolution gas chromatography coupled with a high resolution mass spectrometer. The concentrations of analytes ranged from 0.07 to 0.59 pg g-, fresh weight (fw) and 0.3-19.0 pg g(-1) in L. niloticus and 0.06-0.18 and 0.2-15.7 pg g(-1) in 0. niloticus, for Sigma PCDD/Fs and Edl-PCBs, respectively. Differences in congener concentrations were observed between the two fish species and study sites, and this was attributed to differences in feeding habits and trophic levels. World Health Organization-toxic equivalents (WHO-TEQs) were in the range 0.01-0.16 pg TEQg(-1) for the PCDD/Fs and 0.001-0.74 pg TEQg(-1) for the dl-PCBs. The TEQ values in the present study were lower compared to those of most fish samples reported in literature and were within permissible levels recommended by the European Union, implying that the fish was fit for human consumption

PCDD/Fs and dioxin-like PCBs in surface sediments from Lake Victoria, East Africa.

Surface sediments (<60cm) from the Napoleon Gulf and Thurston Bay on the northern shore of Lake Victoria were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs). Fifteen PCDD/Fs and eleven dl-PCBs were found in 75.5% of the samples. The maximum concentrations of PCDD/Fs and dl-PCBs were 44.1 and 136pgg(-1) dry weight (dw), respectively. Octachlorodibenzo-p-dioxin was the predominant PCDD/F congener at the Napoleon Gulf and Thurston Bay area. Regarding the dl-PCBs, a variation in levels was observed between the mono-ortho PCBs and non-ortho PCBs, with the former having higher levels than the latter. The PCDD/F and dl-PCB levels, in the sediments of Napoleon Gulf, which is near urban centers and industrial areas were markedly higher (α≤0.05) than those from the Thurston Bay, which is offshore, suggesting that human activities could be sources of the pollutants to the surrounding water resources. World Health Organization-toxic equivalency quotients (WHO-TEQs) lay in the range of 0.07-5.53pgg(-1) dw for PCDD/Fs and 0.01-0.23pgg(-1) dw for dl-PCBs. 23.1% of samples from the Napoleon Gulf had their results above the set WHOPCDD/Fs-TEQ value

Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polybrominated diphenyl ethers in sediments and fish species from the Murchison Bay of Lake Victoria, Uganda.

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polybrominated diphenyl ethers (PBDEs) were analyzed in sediments and fish from the Murchison Bay of Lake Victoria by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). Average concentrations of total (Σ) PCDD/Fs and ΣPBDEs in sediments ranged from 68.8 to 479pgg(-1) dry weight (dw) and 60.8 to 179pgg(-1) dw, respectively. Contamination levels of sedimentary PCDD/Fs and PBDEs were low to moderate compared to other urbanized regions worldwide. The concentrations in different fish species (Nile perch; Lates niloticus and Nile tilapia; Oreochromis niloticus) were 5.32 to 49.0pgg(-1) wet weight (ww) for PCDD/Fs and 59.3 to 495pgg(-1) ww for PBDEs. Higher concentrations of the pollutants were found in L. niloticus than O. niloticus, which could be attributed to species differences in feeding habits and lifestyles. World Health Organization-toxic equivalents (WHO2005-TEQs) for PCDD/Fs ranged from 0.08 to 0.33pgTEQg(-1) dw and 0.001-0.14pgTEQg(-1) ww in sediments and fish, respectively. The TEQ values were low compared to the data for fresh water fish reported in literature and within a permissible level of 3.5pgg(-1) ww recommended by the European Commission. Based on the Commission set value and minimum risk level criteria formulated by the Agency for Toxic Substances and Disease Registry, the fish from the Murchison Bay was fit for human consumption