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, ？？=180 bar, time？=？135？mn, CO2 flow rate？=？15？mL·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-CO2:？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-CO2 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). 1. Introduction O. ficus indica is a species of cactus that belongs to the Cactaceae family, the order Centrospermae, and the genus Opuntia. This plant is associated with the semiarid zones of the world mainly in Africa, Mediterranean countries, southwestern United States, northern Mexico, and other areas [1]. In Tunisia, the prickly pear grows everywhere and mainly used for human consumption [2]. In chemistry, the main studies on the Opuntia fruits were the chemical analysis of pulp, skin, and seeds [1]. The proximate composition of O. ficus indica L. has been investigated [1, 3]. Seeds constitute about 10–15% of edible pulp and are usually discarded in the food industry as waste after pulp extraction. Edible oil can be obtained from prickly pear seeds in yield of 5.8–13.6% [1, 4–6]. The oil has a high degree of unsaturation in fatty acids (82%) with a linoleic acid content of 73.4% [5]. According to the investigation of Ramadan and M？rsel [7] using a chloroform/methanol as extraction solvent procedure of total lipids in seeds oil of cactus pear (O. ficus indica L.), linoleic acid was the dominating fatty acid (53.5%), followed by palmitic (20.1%) and oleic acids (18.3%). Two spices of prickly pear from Tunisia, O. ficus indica and O. stricta, were investigated for fatty acid composition seeds by Ennouri et al. [2] with an exceptional level of linoleic acid (up to 70%);
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