Nutritional characterisation of Baobab (Adansonia digitata l.) fruits based on Africa geographical regions

Abstract

Baobab (Adansonia digitata L.) is an indigenous fruit tree occurring in the savannah drylands of sub-Saharan Africa. A vast population of people in this region suffers from hidden hunger and malnutrition. Baobab fruits are a source of micronutrients, and their utilization in local diets has potential to improve health of the rural poor. The present study was conducted to determine the nutritional characteristics of baobab pulp and seeds across Africa geographical regions. Mature baobab fruits were harvested during the ripening stage from provenances established in Kenya, Tanzania, Zambia, Zimbabwe, Malawi, and Mali. The pulp and seed proximate composition was determined using the standard Association of Official Analytical Chemists (AOAC) methods of analyses. Fatty acids (FA) were analysed as fatty acid methyl esters (FAME) using Gas Chromatography-Flame Ionization detector (GC-FID) whereas, pulp vitamin C was quantified using the dichlorophenolindophenol (DCPIP) method. Fruit pulp and seed mineral elements were analysed using inductively coupled plasma-Atomic emission spectrometry (ICP-AES, 9000). Overall, results showed that the nutritive value of baobab varied with the geographical locations. The highest mean pulp vitamin C content was recorded in Taita (4.34 mgg-1) while the lowest was recorded in Malindi (2.31 mgg-1). Pulp crude protein content levels were lower than 3.5 g100g-1 dw across all provenances. At country level, mean pulp crude fibre content was highest (8.83 g100g-1 dw) in Kenya. The highest mean pulp potassium (22.2 mgg-1) and calcium (4300 mgkg-1) levels were recorded in Malawi. Kenya had the highest mean pulp iron (57.4 μgg-1) and manganese (27.2 μgg-1) content while Mali had the lowest iron and manganese at 13.1 μgg-1 and 8.6 μgg-1, respectively. Seed proximate content varied significantly (P < 0.001) across provenance. At country level the mean seed calcium content was highest (3200 mgkg-1) in Malawi and lowest in Kenya (2000 mgkg-1). Oleic, linoleic, palmitic, stearic and linolenic were the most abundant fatty acids of baobab seed oil. Generally, the study reveals that baobab fruits are nutrient dense, and their consumption could alleviate hidden hunger and malnutrion among the rural poor. Evidence provided in this study demonstartes the existence of significant variation in the nutrient content of baobab pulp and seeds among the selected regions. The variation offers opportunities for selecting provenances to obtain germplasm from elite mother trees for both in situ and ex situ conservation, breeding and domestication of baobab.