SUPERCRITICAL CARBON DIOXIDE EXTRACTION OF CITRONELLA OIL FROM CYMBOPOGON WINTERIANUS USING TAGUCHI ORTHOGONAL ARRAY DESIGN

Objective: Optimum condition for the extraction of citronella oil from citronella (Cymbopogon winterianus) using supercritical carbon dioxide (SC-CO2) was investigated.Methods: In order to determine the optimum extraction condition, a Taguchi experiment with L9 orthogonal array design was used. Effects of pressure, temperature and dynamic extraction time on citronella oil yield were investigated at levels ranging between 10-15 MPa, 35-45 °C and 60-180 min, respectively.Results: The highest citronella oil yield (3.206%) was achieved at a factor combination of 15 MPa, 50 °C and 180 min. The obtained citronella oil yield from SC-CO2 extraction was higher than that of percolation as the solvent extraction method using ethanol, which gave a citronella oil yield of 1.4%. The experimental oil yield at optimum condition was in accordance to the values predicted by a computational process using Taguchi method. Analysis of variance (ANOVA) with 95% confidence interval indicates that extraction temperature is the most significant factor in maximizing citronella oil yield, followed by dynamic extraction time and pressure.Conclusion: Optimization process for oil yield from SC-CO2extraction of citronella (Cymbopogon winterianus) was successfully performed using Taguchi L9 orthogonal array design. This study demonstrates that Taguchi method was able to simplify the experimental procedure of SC-CO2 process.