Trace Metal Elements (Pb, Cd and As), 15N Nitrogen and Phosphorus Isotopes Accumulation in Three Varieties of Tomato from Conventional and Agro-Ecological Farming Systems in Burkina Faso

Tomato is a market gardening product that plays an important nutritional and economic role in Burkina Faso. However, the bad use of pesticides for its production could have negative impacts consumers’ health. The objective of the present study was to assess the concentration of trace metal elements (Pb, Cd and As), 15N isotopes (NO2-, NO3-, NH4+) and phosphorus (PO42-) in tomatoes according to cultivation practices. Thus, three tomato varieties (Mongal F1, F1 Cobra 26 and Roma F1) were grown using organic and conventional production methods on 2 sites at Nongr Massom, (commune of Kadiogo province). The trace metal elements were analyzed using atomic absorption spectrophotometry, the isotopes 15N (NO2-, NO3-, NH4+) and phosphorus (PO43-) using standardized methods. Tomatoes from conventional agriculture had higher levels of trace metal elements (0.163 - 0.298 mg/Kg, 0.082 - 0.146 mg/Kg and 0.018 - 0.032 mg/Kg respectively for Pb, Cd and As) than those from organic agriculture samples. Concentration of trace metal is lower for organic production with a reduction of 19.02%, 19.69% and 20.77% for Pb, Cd and As respectively compared to conventional production. High levels were recorded for the Roma F1 variety. The concentrations of trace metal elements in organic production are lower than the codex standards (2010) while those in conventional production are higher. These results could be due to the use of chemical inputs that could have a negative impact on the nutritional quality of these tomatoes. The concentration of trace metal elements in tomato fruits is strongly correlated by production method and less by the variety (genetic).

Physical and Phytochemical Properties of the Rind of Five Watermelon Cultivars

Watermelon is known for its good thirst-quenching power;its important water content is one of its major characteristics. This very juicy character of the fruit associated with an important quantity of by-products constitutes a weak point of profitability to its transformation. Indeed, next to the sweet, juicy, refreshing pulp with exceptional gustative quality, there is a large number of by-products that are not consumed, not valorized, and are considered as waste. This study aims to provide some solutions to this problem, which hinders the processing of watermelon in Burkina Faso. The physicochemical parameters, phytochemical composition, and some biological properties of watermelon rind were evaluated. In other words, substances of nutraceutical interest and their properties were measured in watermelon rind to find useful uses for them. The determination of the dimensions was done by direct measurements. Physicochemical parameters were determined by standard methods. The phytochemical composition was determined by spectrometric methods. The analysis of the samples showed significant variability for the different physical parameters of the fruits. Interesting physical properties such as the water absorption and water holding capacity of the dried rind powder (nearly 1000%) were revealed. Moreover, the fruit rind showed remarkable photochemical composition and antiradical properties. As such, watermelon rind could be incorporated into other culinary preparations, in animal nutrition.