Proximate and phytochemical composition of selected indigenous leafy vegetables consumed in Malawi

Abstract

Indigenous vegetables are very important in nutritional wellbeing of low resource rural communities especially in developing countries. Most indigenous vegetables are also believed to contain health promoting compounds such as antioxidants. In this study, nutrient composition of three commonly consumed indigenous leafy vegetables in Malawi namely Amaranth (Amaranthus species), Black jack (Bidens pilosa) and Mwamuna aligone/gallant soldier (Galinsoga parviflora) was determined. Results showed that crude protein expressed on dry weight basis ranged from 15.83±0.19 to 19.04±0.33 with B. pilosa registering the highest value and G. parviflora the lowest. Results on mineral content showed that G. parviflora had the highest (18.84±0.40% DW) p<0.05 mineral/ash content compared to B. pilosa (13.35±0.07% DW) and Amaranthus spp. (15.48±0.14%). Amaranthus spp. had the highest crude fat (13.17±0.20%) content compared to B. pilosa and G. parviflora which had 9.00±0.29 and 8.97±0.25%, respectively. Antioxidant capacity in mg vitamin C Equiv./g DW, ranged from 49.403±0.105 to 59.186±0.0608 with G. parviflora registering the highest value compared to the other two indigenous vegetables. Total phenolic content ranged from 22639±26.0 to 28672±45.1 mg GAE/kg with Amaranthus spp. registering the highest value and G. parviflora the lowest. Results on anti-nutrient content with respect to phytic and oxalic acids showed that all the three indigenous vegetables contained low and safe levels of antinutrients. The study results have demonstrated the significance of these indigenous vegetables in human nutrition and health for rural people in Malawi.   Key words: Indigenous vegetables, proximate composition, total phenolic compounds, antioxidant capacity, phytochemicals.