Refining and characterization of Parinari polyandra Benth seed oil for industrial utilization

Abstract

Parinari polyandra Benth oil was extracted and refined using the methods of degumming, neutralisation and bleaching with acid activated bleaching earth. The physico-chemical properties of the refined oils were carried out using standard methods and compared with those of the crude. The oils were further characterized by infra-red (IR), atomic absorption spectrometry (AAS) and gas chromatography – mass spectrometry (GC-MS). The refractive index, iodine value and mean molecular weights increased after refining while the saponification and acid values decreased after the successive degumming, neutralization and bleaching steps. The reduction in the intensity of the band at 3330-3545 cm-1 on the IR spectra indicated reduction in free fatty acid content. The GC-MS spectra of the refined oil indicated there are only minimal changes in the composition of the oil after refining. The high content of polyunsaturated fatty acids indicated by the GC-MS spectra and the relatively higher iodine value of 179.66g I2 /100g after refining suggests the quality of the oil can be enhanced for industrial application in alkyd resins and epoxies. The study shows that the refining procedures did not have an unfavourable effect on the composition of the fatty acids.