Optimization of Terminalia neotaliala (Madagascar almond) seed oil yield using central composite design and its fatty acid profiling

Abstract

Non-edible oils are an attractive source for production of biodiesel as they do not impede the availability of foods. In this study, central composite design (CCD) was used to explain the effects of solvent:solute ratio, temperature and extraction time on the yield of non-edible oil from Terminalia neotaliala seed. The solvent used was n-hexane, and response surface methodology was applied to define the optimum process conditions that maximize oil yield. The oil obtained under optimum conditions was transesterified to biodiesel using potassium hydroxide catalyst. American Society for Testing and Materials(ASTM) standards were used in determining the oil’s physicochemical properties, and chemical components of the oil and biodiesel were analyzed with Fourier transform infrared spectroscopy and gas chromatography–mass spectroscopy. The model generated for oil yield was significant at p value, R², adjusted R², and predicted R² of <.0001, 0.9044, 0.8565 and 0.6807, respectively. Optimum oil yield was obtained at 90.0 °C, solvent:solute ratio of 6.89 and 181.67 min. Chemical analysis of the oil showed the presence of carbonyl acid and fatty acid methyl ester (FAME). Total saturated fatty acid was 45.76%, while polyunsaturated fatty acid and FAME components were 34.42% and 4.59%, respectively.

Keywords:

• Terminalia neotaliala
• optimization
• seed oil
• biodiesel
• CCD
• RSM

Acknowledgements

The authors thank the Department of Chemical Sciences, Ajayi Crowther University, Oyo, Nigeria, for making technical assistance available in the course of the research.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.