Production and Evaluation of African Star Apple (Chrysophyllum Albidum) Seed Oil as a Non-Edible Feedstock for Biodiesel Production

Abstract

The ever-increasing demand for sustainable and renewable energy has intensified research into non-edible oil feedstocks for the production of biofuels. This study investigates the production of biodiesel using African Star Apple (Chrysophyllum albidum) seed oil as feedstock. The seeds were processed to remove the seedcoat while oil was extracted from the cotyledon by superheated solvent extraction at varying seed particle sizes of <0.5, 2.0 and 4.0mm respectively. The extracted oil was subjected to physical (density, colour, odour) and chemical characterisation (free fatty acid and acid value, iodine tests). Biodiesel was produced using the two-step reaction process (acid esterification and transesterification) and was tested for its physiochemical properties (density, kinematic viscosity and cetane number) and microstructural properties following the established ASTM and EN standards. The results show that the oil yield varied significantly across particle sizes, with the highest yield obtained from <0.5mm particle size, with an overall average yield of 8.37%. It was observed that the extracted oil contained 3.948% free fatty acid (FFA) content with saponification value of 201.8 mg KOH/g. Furthermore, the biodiesel properties (Density at 0.88g/cm, Kinematic Viscosity at 4.2mm/s, and Cetane Number at 52) were found to be in compliance with the established fuel standards, thus validating the use of C. albidum seed oil as a potential viable biodiesel feedstock. Overall, the physicochemical profile of C. albidum seed oil proves its effectiveness as a viable, alternative biodiesel feedstock.