Supercritical SC-CO2 and soxhlet n-hexane extract of Tunisian Opuntia ficus indica seeds and fatty acids analysis

Abstract

The fatty acids profiles of Tunisian Opuntia ficus indica seeds (spiny and thornless form) were investigated. Results of supercritical carbon dioxide (SC-CO2) and soxhlet n-hexane extract were compared. Quantitatively, the better yield was obtained through soxhlet n-hexane: 10.32 (spiny) and 8.91 (thornless) against 3.4 (spiny) and 1.94 (thornless) by SC-CO2 extract (T=40°C, P = 180 bar, time=135mn, CO2 flow rate=15mL·s-1). Qualitatively, the main fatty acids components were the same for the two types of extraction. Linoleic acid was the major compound, SC-CO2:57.60 (spiny), 59.98 (thornless), soxhlet n-hexane: 57.54 (spiny), 60.66 (thornless), followed by oleic acid, SC-CO 2:22.31 (spiny), 22.40 (thornless), soxhlet n-hexane: 25.28 (spiny), 20.58 (thornless) and palmitic acid, SC-CO2:14.3 (spiny), 12.92 (thornless), soxhlet n-hexane: 11.33 (spiny), 13.08 (thornless). The SC-CO 2 profiles fatty acids showed a richness with other minority compounds such as C20:1, C20:2, and C22. The seeds oil was highly unsaturated (US=4.44-5.25), and the rising temperatures donot affect the selectivity of fatty acids extract by SC-CO2: US=4.44 (T=40°C) and 4.13 (T=70°C). © 2012 Nizar Yeddes et al.