Nutritional Study of Four Leafy Vegetables Produced and Sold in the Southern Zone of Brazzaville (Republic of Congo)

Abstract

Generally overlooked by consumers, many local leafy vegetables in the Republic of Congo are considered to be part of the rural way of life and “poor man's food”. In order to promote their consumption, this study was carried out to assess the nutrient composition of four leafy vegetables (Amaranthus hybridus L, Basella alba, Solanum nigrum L and Ipomea batatas L). The leafy vegetables were collected from two markets and two market garden sites. The pH and the contents in moisture, protein, ash, lipids and minerals (Ca, P, Fe and Mg) were determined using standard analytical methods (Association of Official Analytical Chemists). The results indicate that the four leafy vegetables have a pH of between 6 ± 0.03 and 7 ± 0.04, high moisture content (81.43 ± 0.20 to 94.89 ± 0.12 g/100g FW), high protein content (21.95 ± 0.05 to 32.59 ± 0.07 g/100g FW) and high ash content (13.32 ± 0.05 to 25.78 ± 0.03 g/100g FW). All the vegetables were low in lipids (between 2.73 ± 0.23 and 4.81 ± 0.20 g/100gDW). The investigations also show that the four vegetables studied have high levels of phosphorus (389.27 ± 3.23% to 875.22 ± 3.16 mg/100 g DM), iron (70.29 ± 0.15 to 180.06 ± 1.21 mg/100 g DM), calcium (106.78 ± 3.25 to 3404.57 ± 8.07 mg/100 g DM) and magnesium (679.20 ± 2.25 to 2331.25 ± 3.26 mg/100 g DM). In addition, the vegetables collected at the market garden site of the municipal garden had the best a best Ca/P ratio (2.56 to 4.59). These findings suggest that these leafy vegetables represent a genuine alternative source of protein and especially micronutrients (iron, phosphorus, calcium, magnesium) for human nutrition, health and food safety.