title: Comparative Study of Antioxidant Power, Polyphenols, Flavonoids and Betacyanins of the Peel and Pulp of Three Tunisian Opuntia Forms.
abstract: 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)).
authors.affiliation: Laboratory Applications of Chemical Resources, Natural Substances and the Environment (LACReSNE), Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna-Bizerte, Tunisia. nizaryeddes@yahoo.fr.
authors.forename: Nizar
authors.initials: N
authors.lastname: Yeddes
authors.affiliation: Laboratory Applications of Chemical Resources, Natural Substances and the Environment (LACReSNE), Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna-Bizerte, Tunisia. cherif_j2000@yahoo.fr.|Tunis Preparatory Institute for Engineering Studies (IPEIT), Montfleury, University of Tunis, 1008 Tunis, Tunisia. cherif_j2000@yahoo.fr.
authors.forename: Jamila K
authors.initials: JK
authors.lastname: Chérif
authors.affiliation: INRA, Research Unit Cider, Biotransformation of Fruits and Vegetables (URCBFL), B.P. 35327, F-35653, Rennes Le Rheu, France. Sylvain.Guyot@rennes.inra.fr.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Guyot
authors.affiliation: INRA, Research Unit Cider, Biotransformation of Fruits and Vegetables (URCBFL), B.P. 35327, F-35653, Rennes Le Rheu, France. helene.sotin@rennes.inra.fr.
authors.forename: Hélène
authors.initials: H
authors.lastname: Sotin
authors.affiliation: Laboratory Applications of Chemical Resources, Natural Substances and the Environment (LACReSNE), Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna-Bizerte, Tunisia. malikatrabelsi_ayadi@yahoo.fr.
authors.forename: Malika T
authors.initials: MT
authors.lastname: Ayadi
keywords: Opuntia ficus indica; Opuntia stricta; antioxidant activity; cactus fruit; phenolic compounds