Screening and Characterization of Phenolic Compounds and Their Antioxidant Capacity in Different Fruit Peels

Abstract

Fruit peels have a diverse range of phytochemicals including carotenoids, vitamins, dietary fibres, and phenolic compounds, some with remarkable antioxidant properties. Nevertheless, the comprehensive screening and characterization of the complex array of phenolic compounds in different fruit peels is limited. This study aimed to determine the polyphenol content and their antioxidant potential in twenty different fruit peel samples in an ethanolic extraction, including their comprehensive characterization and quantification using the LC-MS/MS and HPLC. The obtained results showed that the mango peel exhibited the highest phenolic content for TPC (27.51 ± 0.63 mg GAE/g) and TFC (1.75 ± 0.08 mg QE/g), while the TTC (9.01 ± 0.20 mg CE/g) was slightly higher in the avocado peel than mango peel (8.99 ± 0.13 mg CE/g). In terms of antioxidant potential, the grapefruit peel had the highest radical scavenging capacities for the DPPH (9.17 ± 0.19 mg AAE/g), ABTS (10.79 ± 0.56 mg AAE/g), ferric reducing capacity in FRAP (9.22 ± 0.25 mg AA/g), and total antioxidant capacity, TAC (8.77 ± 0.34 mg AAE/g) compared to other fruit peel samples. The application of LC-ESI-QTOF-MS/MS tentatively identified and characterized a total of 176 phenolics, including phenolic acids (49), flavonoids (86), lignans (11), stilbene (5) and other polyphenols (25) in all twenty peel samples. From HPLC-PDA quantification, the mango peel sample showed significantly higher phenolic content, particularly for phenolic acids (gallic acid, 14.5 ± 0.4 mg/g) and flavonoids (quercetin, 11.9 ± 0.4 mg/g), as compared to other fruit peel samples. These results highlight the importance of fruit peels as a potential source of polyphenols. This study provides supportive information for the utilization of different phenolic rich fruit peels as ingredients in food, feed, and nutraceutical products.

Industrial Fruits By-Products and Their Antioxidant Profile: Can They Be Exploited for Industrial Food Applications?

“…The identification was performed by a comparison of their retention times and MS/MS fragmentation patterns with standards. The hydroxybenzoic acids are widely distributed in nature and have been identified by other authors in citrus and apple fruits and products [ 38 , 39 , 40 ]. On the other hand, protocatechuic acid has been described in apple fruits and less in citrus.…”

High-Throughput Screening and Characterization of Phenolic Compounds in Stone Fruits Waste by LC-ESI-QTOF-MS/MS and Their Potential Antioxidant Activities

“…LC-ESI-QTOF-MS/MS characterization of the phenolic compounds in stone fruits waste was performed by Agilent 1200 series HPLC (Agilent Technologies, CA, USA) equipped with an Agilent 6520 Accurate-Mass Q-TOF LC/MS (Agilent Technologies, CA, USA) by following the protocol of Suleria, et al [ 39 ]. The separation of compounds is achieved by using Synergi Hydro-RP 80A LC reverse phase column with an internal diameter of 250 mm × 4.6 mm and particle size of 4 µm (Phenomenex, Torrance, CA, USA).…”

Screening of Phenolic Compounds in Australian Grown Berries by LC-ESI-QTOF-MS/MS and Determination of Their Antioxidant Potential

“…Extensive characterisation of phenolic compounds of four different berries were carried out using the LC-ESI-QTOF-MS/MS and method followed as described by Suleria, Barrow and Dunshea [ 17 ]. An Agilent 1200 series of HPLC (Agilent Technologies, Santa Clara, CA, USA) connected via electrospray ionisation source (ESI) to the Agilent 6530 Accurate-Mass Quadrupole Time-of-Flight (Q-TOF) LC/MS (Agilent Technologies, Santa Clara, CA, USA).…”

“…Identification, quantification and characterisation of phenolics extracted from berries can be achieved by different developed analytical methodologies [ 14 ]. Liquid chromatography integrated with electrospray-ionization, triple quadrupole and two mass spectrometry (LC-ESI-QTOF-MS/MS) is a highly sensitive tool used to identify various phenolic compounds, while high-pressure liquid chromatography (HPLC) combined with photodiode array detector (PDA) is mostly used for quantification purposes of bioactive compounds [ 17 ]. Previously, HPLC and LC-MS analysis of strawberries and blueberries showed the presence of some phenolic compounds including p -coumaric acid derivatives, pelargonidin, quercetin, myricetin, kaempferol and cyanidin [ 18 ] whereas, raspberries and blackberries are rich sources of ellagic acid [ 19 ].…”