Elemental composition and fatty acid profile of the edible fruits of Amatungula (Carissa macrocarpa) and impact of soil quality on chemical characteristics

The Amatungula fruit, from Carissa macrocarpa, is commonly consumed by the local people of KwaZulu-Natal (KZN), South Africa. Levels of elements in the fruit were determined to assess if they conform to recommended dietary allowances (RDAs) and to assess for potential toxicities. Soils and fruit samples from nine sites in eastern KZN were investigated. Concentrations of elements in the fruit were found to be in the order of Ca > Mg > Fe > Mn ≈ Cu ≈ Pb > Se > Cr > Ni > Zn. For the elements in focus, except for Pb, all of the elements found in the fruit contribute significantly towards the RDAs. Lipid profiling was also done to determine the fruits potential as a source of essential fatty acids. The fruit was rich in monounsaturated and essential fatty acids with the linoleic acid to α-linolenic acid ratio conforming to the recommended range for cardiac health. Concentrations of elements in soil had no significant effect on plant concentrations, but competition between elements in soil influenced their availability. Total soil concentrations of most metals studied have significantly correlated Pb availability, indicating the impact of these metals on Pb availability. The Amatungula fruit showed tendency to accumulate Pb, with Pb levels in fruit at all sites being toxic to human health. Site location had a major effect on plant concentrations however uptake and distribution was primarily dependent on the plants inherent controls, as evidenced by the accumulation and exclusion of elements, to meet its physiological requirements.

Impact of soil quality parameters on elemental concentration in the Amatungula fruit.Figure optionsDownload as PowerPoint slideHighlights
► Elements in fruit contribute significantly to the diet of most individuals.
► Plant accumulated Pb at toxic levels, showing influence of site on toxicity.
► Soil concentrations did not affect plant concentrations but site location did.
► Competition in soil influenced metal availability, but uptake depended primarily on plant.