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Antioxidants 2015, 4(3), 498-512;

HPLC-DAD Phenolic Characterization and Antioxidant Activities of Ripe and Unripe Sweet Orange Peels

Department of Food Science and Technology, Federal University of Technology, P.M.B. 704, Akure 340284, Nigeria
Department of Biochemistry, Federal University of Technology, P.M.B. 704, Akure 340284, Nigeria
Phytochemical Research Laboratory, Department of Industrial Pharmacy, Federal University of Santa Maria, Build 26, Room 1115, Santa Maria, CEP 97105-900, Brazil
These authors contributed equally to this work.
Author to whom correspondence should be addressed.
Academic Editors: Antonio Segura-Carretero and David Arráez-Román
Received: 5 April 2015 / Revised: 19 June 2015 / Accepted: 19 June 2015 / Published: 9 July 2015
(This article belongs to the Special Issue Analytical Determination of Polyphenols)
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Phenolic compounds of unripe and ripe sweet orange peels were determined using a high-performance liquid chromatography separation method with diode array detector (HPLC-DAD). The in vitro antioxidant properties and the EC50 (concentration required to obtain a 50% antioxidant effect) values were also determined. The predominant phenolic compounds were quercitrin, rutin, and quercetin with values of 18.77 ± 0.01 mg/mL, 18.65 ± 0.03 mg/mL, and 10.39 ± 0.01 mg/mL respectively in unripe orange peel and 22.61 ± 0.01 mg/mL, 17.93 ± 0.03 mg/mL, and 14.03 ± 0.02 mg/mL respectively in ripe orange peel. The antioxidant properties revealed 2,2′-azino-bis(3-ethyl benzothiazoline-6-sulfonic acid) diammonium salt (ABTS) scavenging ability of both unripe and ripe orange peels respectively as 14.68 ± 0.01 and 16.89 ± 0.02 mmol TEAC/g, the Ferric Reducing Antioxidant Properties (FRAP) as 70.69 ± 0.01 and 91.38 ± 0.01 mg gallic acid equivalents/100g, total phenol content as 5.27 ± 0.03 and 9.40 ± 0.01 mg gallic acid equivalents/g and total flavonoid content as 3.30 ± 0.30 and 4.20 ± 0.02 mg quercetin equivalent/g. The antioxidant assays showed enhanced potency of extract from ripe orange peel with EC50 values of 2.71 ± 0.03 mg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 0.67 ± 0.03 mg/mL for hydroxyl radicals (OH*), 0.57 ± 0.02 mg/mL for Fe2+ chelation, and 0.63 ± 0.06 mg/mL for malondialdehyde (MDA), and was more potent than unripe orange peel. View Full-Text
Keywords: orange peel; phenolic profile; in vitro antioxidant orange peel; phenolic profile; in vitro antioxidant

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Omoba, O.S.; Obafaye, R.O.; Salawu, S.O.; Boligon, A.A.; Athayde, M.L. HPLC-DAD Phenolic Characterization and Antioxidant Activities of Ripe and Unripe Sweet Orange Peels. Antioxidants 2015, 4, 498-512.

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