A preliminary investigation into the biofuel characteristics of tigernut (Cyperus esculentus) oil

Laboratory scale experiments were carried out to produce and characterise biofuel from tigernut (Cyperus esculentus) oil. Transesterification of tigernut oil afforded methyl and ethyl esters, which had fuel properties similar to common biofuels, hence tigernut could be utilised as an alternative renewable energy resource.

Chemical composition of seeds and oil of Xylopia aethiopica grown in Nigeria

The chemical composition and mineral constituents of Xylopia aethiopica, which is valued as a spice in Nigeria, were determined along with the physicochemical characteristics of the seed oil. The seeds had the following chemical compositions moisture (8.43 g/100 g), ash (5.89 g/100 g), crude lipid (9.58 g/100 g), crude protein (12.45 g/100 g) crude fiber (8.66 g/100 g) and carbohydrate (63.65 g/100 g). Calcium and potassium were the major minerals in the seed. The extracted lipid was examined for fatty acid composition. Linoleic (45.1 g/100 g) and oleic (26.5 g/100 g) acids were the predominant unsaturated fatty acids, while palmitic acid (18.0 g/100 g) was the major saturated acid. The iodine value of 97 g/100 g indicates that the seed oil is a non-drying type.

Nutrient content of Prosopis africana seeds

The proximate and mineral compositions of Prosopis africana seeds used in the preparation of a local condiment in Nigeria and as animal feed were investigated. The proximate analysis showed that protein, ash and fiber values were comparable to Parkia africana seeds. However, the crude lipid content was lower than Parkia filicoidea seeds and decorticated groundnut. Phosphorus, potassium and calcium were the major mineral elements of the seeds, thereby suggesting that they could contribute partially to the overall daily intake of these elements.

Mineral composition of non-conventional leafy vegetables

Six non-conventional leafy vegetables consumed largely by the rural populace of Nigeria were analyzed for mineral composition. Mineral contents appeared to be dependent on the type of vegetables. Amaranthus spinosus and Adansonia digitata leaves contained the highest level of iron (38.4 mg/100 g and 30.6 mg/100 g dw, respectively). These values are low compared to those for common Nigerian vegetables but higher than those for other food sources. All the vegetables contained high levels of calcium compared to common vegetables, thus they could be a rich source of this mineral. Microelement content of the leaves varied appreciably. Zinc content was highest in Moringa oleifera, Adansonia digitata and Cassia tora leaves (25.5 mg/100 g, 22.4 mg/100 g and 20.9 mg/100 g dw, respectively) while the manganese content was comparatively higher in Colocasia esculenta. The concentrations of the mineral elements in the vegetables per serving portion are presented and these values indicate that the local vegetables could be valuable and important contributors in the diets of the rural and urban people of Nigeria. The mean daily intake of P, Mg, Ca, Fe, Cu and Zn were lower than their recommended dietary allowances (RDAs). However, the manganese daily intake was found not to differ significantly (p = 0.05) from the RDA value.