The seeds of C. inophyllum were dried under sunlight for 2–3 days. The kernel was then separated from the shell and found to have high oil content (70%). The ideal conditions to preserve the kernel are 26–27°C and 60–70% humidity. The place in which the kernel is stored must be well ventilated and the storing period should not be too long.

The kernels of the P. edule fruits were obtained manually and cleaned before being dried overnight in an oven at 353 K. Moderate temperature for the drying of the P. edule kernels was used to prevent possible decomposition or oxidation of the kernels at higher temperature (>373 K) at which the properties of the extracted oil could be affected. The dried P. edule kernels were ground to fine particles using food processor and then dried for the second time in the oven to remove excess moisture. The oil extraction process was carried out using Soxhlet apparatus and the duration of each extraction process was set at about 4 h under temperature of 343 K (reflux temperature of the solvent). P. edule oil was obtained after separating the mixture of solvent and oil using rotary evaporator. The resultant P. edule oil was decanted mechanically to remove impurities and other components (glycosides) that may be present in the oil [50].