An experimental design approach for the extraction of volatile compounds from turmeric leaves (Curcuma domestica) using pressurised liquid extraction (PLE)

Pressurised liquid extraction (PLE) was used to obtain an oleoresin from aromatic turmeric leaves. Four major compounds, which constituted 72% oleoresin, were monitored during the optimisation study. Components in the extract were identified using GC/MS and retention indices. Based on maximum extraction of 1,8-cineole, the optimised operating conditions for PLE, were heating at 147 °C, a pressure of 7150 kPa and a static time of 17 min. The results obtained were compared with conventional isolation procedures, hydrodistillation and Soxhlet extraction, whereby the proposed method was found to be better in term of quantity of the targeted oleoresin compounds, namely, α-phellandrene, p-cymene, 1,8-cineole and terpinolene.