The rise in global energy demand has encouraged exploring into other innovative methods of generating renewable fuels from different forms of waste. Due to its accessibility, culinary used vegetable oil is regarded as a potential source for profitable production of biodiesel. In the present study, the viability of producing biodiesel from used vegetable oil (UVO) by utilizing CaO catalyst (derived from the calcination of chicken eggshell and impregnated with KNO₃ and NaNO₃) was studied. Higher yield of biodiesel was obtained at methanol/oil mole ratio of (9–10) and CaO catalyst concentration of (2.0–3.0) wt/wt% Oil, for the three forms of catalyst used. Also, higher yield of biodiesel was obtained when CaO with impregnated KNO₃ was used, followed by the operation involving CaO with impregnated NaNO₃. At optimum conditions of methanol/oil mole ratio of 9 and catalyst concentration of 2.4 wt/wt% Oil, the yields of biodiesel obtained were 90% (for unimpregnated catalyst), 92% (using CaO impregnated with NaNO₃) and 95% (using CaO impregnated with KNO₃). The higher biodiesel yield obtained for CaO impregnated with KNO₃ (compared to the yield from CaO impregnated with NaNO₃) could be traced to a more reactive nature of potassium and arrangement of electrons of both potassium and sodium. The results of the tests and analysis on biodiesel properties reveal that quality biodiesel were produced from the three forms of catalyst used. This is because, each of the values of the properties considered falls within the ASTM standard.

Utilization of lesser-known food plants through value added processing is a way to develop more sustainable and healthy diets. Pachira glabra seed (Malabar chestnut) was processed into snack (Kuli-kuli) and evaluated for nutrient content and acceptability using standard methods. Proximate composition revealed that P. glabra seed and its seed cake contain 15.75% and 17.50% crude protein and 32.75% and 38.50% carbohydrate, respectively. Mineral constituent of the seed and its seed cake revealed potassium (K) 58.32 mg/kg and 53.01 mg/kg, calcium (Ca) 8.3 mg/kg and 16.9 mg/kg, magnesium (Mg) 10.2 mg/kg and 11.07 mg/kg, respectively. Sensory score shows that P. glabra seed cake was acceptable (p<0.05) in terms of flavour, taste and crispness, compared with groundnut seed cake. The study showed that the seed cake was rich in nutrients. Also, processing of P. glabra into value added product will prevent wastage of natural resource and increase food available for man.

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