Abstract In this work, optimization of oil extraction from the Citrussinensis (C. sinensis) oilseed was carried out. The physiochemical properties of the seed oil were determined for its aptness for industrial application. This was with a view to add value to C. sinensis oil and finding environmentally friendly alternative to conventional oil. sinensis oil seed was obtained from the fruit garden market in Port Harcourt, River State. Nigeria. The seeds were washed to remove dirt, after which the seeds were sun dried until a constant weight was obtained. The dried seeds were de-husked, winnowed, and further sun dried for two days before milling. The oil was extracted using solvent extraction method (n-hexane). For the optimization of the oil extraction, a three-level-three-factors response surface methodology (RSM) and artificial neural network (ANN) were employed. Seventeen (17) experimental runs were generated and were carried out. Independent factor considered were powder weight, solvent volume and extraction time. The physiochemical and other parameters (cetane number, API, aniline point among others) properties were determined using standard methods.
Results showed the that experimental C. sinensis oil yield (CSOY) of 52.64 (% w/w) was obtained, but RSM predicted CSOY of 50.240 (% w/w), validated as 49.98 (% w/w) at powder weight of 40 g, solvent volume of 180 ml and extraction time of 40 min. ANN predicted CSOY of 51.720 (% w/w), validated as 50.85 (% w/w) at powder weight of 43 g, solvent volume of 202 ml and extraction time of 41 min. Physicochemical analysis of CSOY showed the oil to be golden yellowish in colour with specific gravity of 0.9200. The moisture content of 0.0134%, refractive index of 1.5019, FFA of 2.23 which corresponds to acid value of 4.46 mg KOH/g, the saponification value of the oil was 77.14 mg KOH/g while peroxide value of 17.00 was obtained. The iodine value of 78.1 g I2 /100 g with cetane number of 99.48 was obtained for the oil. Higher heating value of the oil was 45.10 MJ/kg. The API gravity of 22.3 and high aniline point of 557.31 of the oil shows that C. sinensis oil is of a better diesel oil. Gas chromatography analysis to determine the free fatty acid of the oil showed the oil to be unsaturated (60.13%).
Hence, the study concluded that C. sinensis oils could serve as feedstock for animals and as lubricant for Industrial purposes.