Studies on the chemical composition and physicochemical properties of the seeds of baobab ( Adasonia digitata)

Abstract

The seeds of baobab used in preparation of local condiments was analysed to establish the proximate composition and the physico-chemical characteristics of the oil and effect of storage on the oil. Results obtained showed that the saponification value (SV), iodine value (IV), peroxide value (PV), acid value (AV), percentage free fatty acid (%FFA) and refractive index of the oil are 196 ± 0.05 mg/KOH, 87 ± 0.02 g/100 g, 4.5 ± 0.06 mEq/kg, 0.33 ± 0.03 mgKOH/g, 0.45 ± 0.08 and 1.459 ± 0.13, respectively. Proximate analysis showed that protein (21.75 ± 0.12 g/100 g), ash (5.01 ± 0.07 g/100 g) and fiber (6.71 ± 0.003 g/100 g) were comparable to Prosopsis africana seeds (20.54 ± 0.18, 6.67 ± 0.08 and 5.51 g/100g), which is used for the same purpose. The crude lipid content (12.72 ± 0.01 g/100 g) was almost equal to that of P. africana seeds (12.74 g/100 g). The major mineral elements present in the seeds included phosphorus,
calcium and potassium (6.00 ± 0.02, 58.90 ± 2.34 and 280.00 ± 1.34 mg/100 g, respectively), thereby suggesting that the baobab seeds could contribute partially to the overall daily intake of these
elements. The vitamins (A and C) found present in baobab seeds are higher than that of P. africana seeds. The antinutritional factors including oxalate, phytate, saponin and tannin (10.31 ± 1.00, 2.00 ±
0.31, 7.16 ± 0.01, 2.84 ± 0.30%, respectively) are also comparable to that of P. Africana. The storage property of the oil from baobab seeds studied over a period of four weeks under conditions of light
(ambient), darkness (ambient), and refrigeration showed that the iodine value of the oil decreased in all cases but much more so on exposure to light. In contrast, the peroxide value of the oil showed very
little change under conditions of darkness and refrigeration over the same period, thus indicating that the oil can withstand storage.