Elemental composition and nutritional value of the edible fruits of coastal red-milkwood (Mimusops caffra) and impact of soil quality on their chemical characteristics

ABSTRACT

In this study, the elemental distribution of essential and toxic elements in the soil and fruits of the indigenous plant species, Mimusops caffra, from ten sites along the KwaZulu-Natal east coast was investigated using inductively coupled plasma-optical emission spectrometry. This was done to determine the nutritional value of the fruits as well as to evaluate the impact of soil quality on elemental uptake by the plant. The elemental concentrations in the fruits (in descending order) were found to be K > Na > Ca > Mg > Si > Al > Fe > Zn > Mn > Ni > Cr > Cu > Pb > Mo > Sb > As > Se > V > Cd > Co. The results show that approximately 10 g of fruit would contribute more than 85% towards the recommended dietary allowance for Fe and Si for most adults. The proximate chemical composition revealed the fruits to contain approximately 84% moisture, 4.7% ash, 6.9% protein, 1.7% oil and 2.7% carbohydrates. The study indicates that the fruits of this indigenous plant species are a good source of essential elements with low levels of potentially toxic elements (Pb, As and Cd) which makes the plant a good indigenous food source especially for vulnerable communities that need food security.

KEYWORDS:

• Geo-accumulation index
• toxic elements
• nutritional value
• synergy
• antagonism

Acknowledgments

The authors acknowledge the University of KwaZulu-Natal for financial support and laboratory facilities.