Antioxidant capacity and UPLC–PDA ESI–MS polyphenolic profile of Citrus aurantium extracts obtained by ultrasound assisted extraction

Abstract

This study aimed to evaluate different pretreatments and solvent ratios on the total phenolic content and antioxidant activity of Citrus aurantium (sour orange) peel extracted by ultrasound. A two-factor (2 9 3) factorial design was implemented, with fresh and dry peels as pretreatment conditions, and water (100%), 50% aqueous ethanol (v/v) and 96% aqueous ethanol (v/v) as the solvents. The phenolic compounds were identified and quantified by ultra-performance liquid chromatographyphotodiode array and electrospray ionisation-mass spectrometry, respectively. The compounds were partially purified by advanced automated flash purification. The results indicated that the maximal phenolic content (40.95 ± 3.44 mg gallic acid equivalents/g dry weight) was obtained when fresh sour orange peels were extracted with 50% (v/v) aqueous ethanol while the maximal antioxidant activity (730.04 ± 28.60 lmol Trolox equivalents/g dry weight) was achieved from aqueous extraction of dry sour orange peels. Nine phenolic compounds were identified and quantified. Naringin and neohesperidin predominated in sour peel extracts, whereas, caffeic and chlorogenic acids were the least abundant. Evaluation of the antioxidant activity in the fractions suggested that this activity might be attributed to the synergistic effect of the nine phenolic compounds present in the crude extract. Accordingly, sour orange peel is a potential source of phenolic compounds with antioxidant activity.

The Effect of Drying Temperature on the Phenolic Content and Functional Behavior of Flours Obtained from Lemon Wastes

“…According to our previous work [46], where a phenolic extract of Citrus aurantium was partially purified, a synergic effect of phenolic compounds was suggested after the higher antioxidant activity found in the crude extract in comparison with the purified fractions at a specific TPC. These results were also reported by Shiraishi et al, [47] who evaluated the antioxidant activity of the phenolic compounds in table grapes.…”

Antimicrobial Efficacy of Fruit Peels Eco-Enzyme against Enterococcus faecalis: An In Vitro Study

“…The synergistic effect of the two eco-enzymes increases the potency of their antimicrobial activity against a wide range of bacteria [21]. The high content of polyphenolic compounds and flavonoids in pineapple and orange peel extracts are found to be responsible for their excellent antimicrobial and antioxidant activities [22,23]. Bromelain from pineapple extracts is shown to be effective in killing Enterococcus faecalis by disrupting the peptidoglycan and polysaccharide components of bacterial cell membranes [24].…”

Physicochemical and Optical Characterization of Citrus aurantium Derived Biochar for Solar Absorber Applications

“…In this sense, the valorization of this type of waste is an attractive approach that could offer useful alternatives through the production of value-added chemicals, fuels, and advanced carbon materials [ 1 , 3 ]. In particular, in Mexico, an average of 4.2 million metric ton of citrus is produced per year, from which 90% is dedicated to fresh consumption and 10% is used in the juice and concentrates industry, generating a high amount of waste, where 40−60% of citrus becomes waste, including peels, seeds, and membranes [ 4 , 5 ].…”

“…Among other varieties of citrus fruits, sour orange ( Citrus aurantium ) is less used for fresh consumption due to its sourness; instead, sour orange juice is often used as an ingredient in meat marinades or salad dressings. For the Citrus sinensis variety, current research has shown that sour orange peel (SOP) can be used as a source of added value compounds such as essential oils, pectin, phenolic compounds, and flavonoids, as well as flavoring and acidifying agents for food [ 5 , 7 , 13 , 14 , 15 ].…”