Nutritive and anti-nutritive qualities of mostly preferred edible woody plants in selected drylands of Iringa District, Tanzania

Abstract

Nutritional and anti-nutritional factors of preferred woody plants were evaluated in selected drylands of Iringa District. Vangueria infausta (Burch.) and Vitex mombassae (Vatke.) identified as source of edible fruits; Adansonia digitata (L.) and Sterculia africana (Lour.) were preferred for oil products whereas Opilia amentacea (Roxb.) and Maerua angolensis (DC.) were used as sources of vegetables. The nutrients and anti-nutrients were evaluated using laboratory standard methods. Results show that there were significant differences (p<0.05) in percentage moisture content, dry matter, crude protein, crude and carbohydrates in all species used as sources of oils, vegetables and fruits. Percent ash content was different among the preferred species for vegetables and fruits. S. africana as oil producing plants had higher protein content (<25%). O. amentacea and M. angolensis had higher crude protein percent (14-34%) than other species. Crude fiber for all preferred species ranged from 9-27.6% on dry weight basis. The crude lipid content of preferred species ranged from 1.2% for fruit plants to 6.80% for oily plants. V. infausta and A. digitata had high Carbohydrates whereas all edible plants had higher values of Potassium and low Copper, Iron and Zinc content. A. digitata seeds had the highest value of Vitamin C (57.31 mg/100 dry weight) and low levels of tannins and phenols. This study concludes that wild plants are nutritious and have adequate nutrients and levels of anti-nutrients are below the toxic levels. Consequently, use of wild food plants could provide a possible source of food security in Iringa District.