Optimization of Oil Extraction from Jojoba Seeds of Mesaoria Plain in Screw Expelling Using Taguchi Design

Abstract

Jojoba oil is widely used in cosmetic, pharmaceutical and lubricant applications. It can also be used as a feedstock in biodiesel production or as a substitute to fuels to improve their properties. Due to its unique characteristics, the present study was focused on the optimization of the oil extraction yield from jojoba seeds in a screw expeller while retaining the oil quality. The seeds used were harvested from the new experimental jojoba plantation grown on Mesaoria Plain of Cyprus Island. The effects of the seed size, humidity level and temperature together with residual discharge opening of the expeller were studied in details and optimized using Taguchi method. The larger-the-best signal to noise ratio (S/N ratio) analysis together with the analysis of variance (ANOVA) were used during optimization. The order of influences was found as (1) seed temperature, (2) seed size, (3) seed humidity level and (4) residual discharge opening according to the S/N ratio analysis. The ANOVA yielded a comparable result however, seed size and temperature exchanged places in the sequence due to slight differences. The optimized extraction conditions were found when seed size was halved, seed temperature was kept at 22°C, no drying was applied on the seeds prior to extraction and residual discharge opening was adjusted to its fully open position. The optimum conditions were verified with the confirmation experiments. The kinematic viscosity and lubricity remained almost unchanged during the experiments.