The antioxidant activity and the chemical composition of methanol extracts from peel and pulp belonging to two species of Tunisian prickly pears Opuntia ficus indica (spiny and thornless forms) and Opuntia stricta have been studied. The antioxidant capacity was measured by DPPH radical scavenging activity. The total phenolic compound (TPC) and the total flavonoid content were determined by the Folin–Ciocalteu method and colorimetric method, respectively. The phenolic compounds were identified and quantified by high-performance liquid chromatography (HPLC) coupled with an electrospray ionization mass spectrometry (ESI-MS). The results showed that O. stricta fruits present the best antioxidant activities than the two forms of O. ficus indica, while the TPC was more important in O. ficus indica than in the O. stricta fruits. The peels have higher flavonoids than pulp, and the thornless variety has more flavonoid than the spiny. The RP-HPLC and ESI-MS analysis detected two classes of phenolic compounds and betalain pigments. Isorhamnetin derivatives are the dominant flavonol glycoside identified in O. ficus indica (spiny: 65.25 μg·g−1; thornless: 77.03 μg·g−1) and O. stricta peels (19.22 μg·g−1).

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 = 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).

The antioxidant activity and the chemical composition of methanol extracts from peel and pulp belonging to two species of Tunisian prickly pears Opuntia ficus indica (spiny and thornless forms) and Opuntia stricta has been studied. The antioxidant capacity was measured by DPPH radical scavenging activity. The Total Phenolic Compound (TPC) and the total flavonoid content were determined by the Folin-Ciocalteu method and colorimetric method, respectively. The phenolic compounds were identified and quantified by High Performance Liquid Chromatography (HPLC) coupled with an electrospray ionization mass spectrometry (ESI-MS). The results showed that O. stricta fruits present the best antioxidant activities than the two forms of O. ficus indica while the TPC was more important in O. ficus indica than in the O. stricta fruits. The peels have higher flavonoids than pulps and the thornless has more flavonoid than the spiny. The RP-HPLC and ESI-MS analysis detected two classes of phenolic compounds and betalain pigments. Isorhamnetin derivatives are the dominant flavonol glycoside identified in O. ficus indica (spiny: 65.25 μg g(-1); thornless: 77.03 μg g(-1)) and O. stricta peels (19.22 μg g(-1)).

No abstract

No abstract