*2.1. Chemicals*

Metaphosphoric acid, 2,2-diphenyl-1-picrylhydrazyl (DPPH), NaOH, nitro-blue tetrazolium, dichlorophenol-indophenol (DCPID), 2,2 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) di-ammonium salt (ABTS•+), 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxyl acid (Trolox), phenazine methosulphate, ethanol, gallic acid, ethylene-diamine-tetra acetic acid (EDTA), ferrozine, 2,4,6-tris (2-pyridyl)-s-triazine (TPTZ), and iron sulphate heptahydrate were purchased from Sigma Chemical Co. (St. Louis, MO, USA). HPLC-grade methanol and acetonitrile (Sigma Aldrich, St. Louis, MO, USA, 99.99%), acetone (Sigma Aldrich, 99.5%), deionized water, formic acid (Carlo Erba, 95%), and hydrochloric acid (Carlo Erba, 37%) were used for sample extraction and HPLC analysis. All chemical standards—gallic acid; protocatechuic acid; procyanidin 1 and 2; syringic acid; *p*, *m*, *o*-coumaric acids; pelargonidin; *trans*-cinnamic acid; bergamottin; cyanidine 3 *O*-glucoside; catechin; vanillic acid; epicatechin; delphinidin; *trans*-4-hydroxycinamic acid; sinapinic acid; 3-hydroxycinnamic acid; myricetin; luteolin; punicalagin; 2,5 dihydroxy benzoic acid; caffeic acid; ellagic acid; naringin; apigenin-7-neohesperosside; spiraeoside; quercetin; kaempferol; tocopherol; chlorogenic acid; vicenin 2; eriocitrine; rutin; vitexin; quercitin-3 beta-D-glucoside; ferulic acid; and apigenin were purchased from Sigma Aldrich, St. Louis, MO, USA. Other chemicals were of analytical grade and purchased from Carlo Erba Reagents s.r.l. (Milan, Italy).

#### *2.2. Pomegranate Peel Preparation and Extraction*

Fruits of the cultivar Wonderful grown in Calabria were washed and hand peeled. The peel of mature Wonderful fruits was dried in different ways: (1) with an innovative process by Gioia Succhi, a Calabrian food transformation industry, that used a physical spray-dried innovative process (PDS) that is held as an industry secret, and (2) stored a −80 ◦C for two days and then lyophilized with a freeze-dry system (Cheimika, SH Top, Pellezzano SA, Italy) at −56 ◦C for 96 h (FD). The dried peels were analyzed for chemical characteristics.

#### *2.3. Sample Extract Preparation*

The extracts were obtained using the method described in Muscolo et al. (2020) [25]. Briefly, lyophilized pomegranate peels were extracted at room temperature (22–25 ◦C) with continuous stirring for 90 min with 15 mL 95% ethanol. The samples were centrifuged (Unicen 21 RT167, Ortoalresa Inc., Madrid, Spain) at 2370× *g* (4000 rpm) for 15 min and the supernatants were filtered with 1 mm Whatman 185 filter paper (Merck, Darmstadt, Germany), evaporated to dryness in a rota-vapor (Diagonal condenser RE 400, Stuart Equipment, ST15, Stone, UK), and re-suspended in a final volume of 3.0 mL 95% ethanol.

Lyophilized pomegranate peels were extracted at room temperature with continuous stirring for 60 min with 2.0 mL dH20 (Intercontinental Mod still 3/ES, Bioltecnical Service, s.n.c., Rome, Italy). The samples were then centrifuged at 590× *g* (2000 rpm) for 10 min and the supernatants were filtered with Whatman 1 filter paper and used for the determination of protein, carbohydrates, and ferrous chelating activity.
