foods Article Screening and Characterization of Phenolic Compounds and Their Antioxidant Capacity in Different Fruit Peels Hafiz A. R. Suleria 1,2,* , Colin J. Barrow 2 and Frank R. Dunshea 1,3 1 School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3010, Australia;
[email protected] 2 Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, VIC 3217, Australia;
[email protected] 3 Faculty of Biological Sciences, The University of Leeds, Leeds LS2 9JT, UK * Correspondence: hafi
[email protected]; Tel.: +61-4-7043-9670 Received: 6 August 2020; Accepted: 28 August 2020; Published: 1 September 2020 Abstract: Fruit peels have a diverse range of phytochemicals including carotenoids, vitamins, dietary fibres, andphenoliccompounds, somewithremarkableantioxidantproperties. 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.