PHYSICO-CHEMICAL, FUNCTIONAL AND ANTIOXIDANT PROPERTIES OF NEGRO PEPPER (XYLOPIA AETHIOPICA) SEEDS, PODS AND CALYX

Abstract

Three different parts (seeds, Pod and Calyx) were separated from a freshly harvested matured stalk of Negro pepper (Xylopia aethiopica) plant to prepare powders. The plant parts were sorted, oven dried at a temperature of 500C until adequately dried and milled into powders. The nutritional potentials of three different parts of this Nigerian medicinal plant (Xylopia aethiopica) used by pregnant women in the Western part of Nigeria were evaluated. The chemical composition, amino acid, mineral content and antioxidant properties of the samples were carried out using standard methods. The results revealed the presence of bioactive constituents comprising saponins (35.91 to 166.01mg/g), phytic acid (7.68 to 34.61mg/g), flavonoids (0.09 to 0.36mg/g), tannis (0.01 to 0.41mg/g), oxalate (0.99 to 1.80mg/g), alkaloids (0.20 to 0.41mg/g), total phenol (14.38 to 46.88mg/ml); Also, Fe2+ chelating; 1, 1- diphenyl-2 picryl-hydrazyl free radical scavenging ability and ferric reducing antioxidant properties of 5.56 to 73.61g/100g; 81.55 to 94.71 g/100g and 0.11 to 0.96mg/ml respectively. Significantly, the full fat samples were higher of antioxidants than the defatted. The medicinal plant parts contained a range of total essential amino acid (18.70 to 33.80mg/g). The crude fat, protein and fibre of the seed was significantly higher than the other two parts which may be due to the fact that it was an oil seed and the seed had a hard covering shell, while the defatted were significantly higher in crude protein, total ash, crude fibre and carbohydrate than the full fat. The result of the functional properties revealed that the defatted samples have higher values ofwater absorption, oil absorption and foaming capacities, foaming stability than the full fat samples which may be due to the fact that oil is an antifoaming agent. However, the full fat samples were significantly higher in bulk density than the defatted samples. These herb parts are good sources of mineral element such as Ca, P, K, other mineral elements detected in reasonable amounts were Mg, Na, Fe, and Zn. While some other non-environmentally friendly heavy metals such as cadmium, chromium, Selenium and Lead were not detected. The result for the antinutritional composition show that calyx had the highest saponin both in the full fat and defatted samples than the seed and the pod which may be attributed to the distinct bitter taste of the calyx and the results of this research indicated that the three plant parts have nutritional qualities that could provide the users with additional nutrients