Characterization of Bioactive Compounds in Tunisian Bitter Orange (Citrus aurantiumL.) Peel and Juice and Determination of Their Antioxidant Activities

Abstract

Citrus aurantium peel and juice aroma compounds were investigated by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS), whereas phenolic compounds analysis was performed by reversed-phase high-performance liquid chromatography (RP-HPLC). Limonene was the major volatile compound of bitter orange peel (90.25%) and juice (91.61%). HPLC analysis of bitter orange peel and juice methanolic extracts indicated that phenolic acids constitute their main phenolic class representing 73.80% and 71.25%, respectively, followed by flavonoids (23.02% and 23.13%, resp.). p-Coumaric and ferulic acids were the most abundant phenolic compounds representing 24.68% and 23.79%, respectively, in the peel, while the juice contained 18.02% and 19.04%, respectively. The antioxidant activities of bitter orange peel and juice methanolic extracts have been evaluated using four in vitro assays, and the results were compared with the standard antioxidants (BHT, BHA, and ascorbic acid). Our findings demonstrated that Citrus aurantium peel and juice possess antioxidant activities which were less effective than those of antioxidant standards. Both extracts may be suggested as a new potential source of natural antioxidant.

Chemical Composition and Antioxidant Activity of Essential Oil Obtained from Bitter Orange Peel (Citrus aurantium L.) Using Two Methods

“…According to previous compositional studies of the bitter orange peel oil, monoterpene hydrocarbon limonene was a major compound. [8,9] These findings agree with our results where limonene was also found to be a dominant component in both samples, i.e. the oil obtained by hydrodistillation (91.1 %) and in the oil obtained by cold pressing method (51.3 %).…”

“…[8][9][10] The absence of hexadecanoic acid from oils in other reports may be due to insufficient running time during GC analysis since hexadecanoic acid, due to hydrophobic interactions, has retention time shifted to higher values. The high percentage of hexadecanoic acid in the cold pressing oil sample may also correlate to concomitant use of a non-polar solvent (diethyl ether) for recovery of essential oil from the mixture.…”

“…[11] Citrus essential oils have a wide range of uses. Because of its pleasant citric fragrance and safety, [9] limonene is commonly used as a flavouring agent in foods, pharmaceuticals and drinks. Due to its high limonene content auranti amari flavedo oil represents a valuable source of limonene.…”

Peels of Lemon and Orange as Value-Added Ingredients: Chemical and Antioxidant Properties

“…No single method can evaluate total antioxidant activity of foods. Two or more methods should always be employed to evaluate the total antioxidative effects of vegetables (Pellegrini, et al, 2003;Nuutila et al, 2003) The antioxidant activity of peel extract might be due to the reduction of superoxide anion, inactivation of free radicals, or complexion with metal ions or their combination (Karoui and Marzouk, 2013). Two complementary test systems: carotenelinoleic acid and DPPH were applied by Moulehi et al, (2012) for evaluating the antioxidant capacities.…”

An effective integrated method for comprehensive identification of eighty-five compounds in Zhi-Zi-Da-Huang decoction by HPLC-DAD-ESI-MS (TOF) and HPLC-DAD-ESI-MS/MS (QqQ) without the help of reference standards

“…52 Peak 65, 74 showed [M + Na] + ions at m/z 750, 726 and [M À H] À ions at m/z 726, 702, respectively, suggesting they were cyclic peptides consisting of several amino acids. Identication of other compounds.…”