**1. Introduction**

Pomegranate (*Punica granatum* L., Lythraceae) is a tree native to the Middle East, now cultivated worldwide, especially in Mediterranean countries, China, Southeast Asia, and other tropical or dry areas [1]. Except for its delightful taste, its peel, fresh seeds, juice and leaves hold a broad gamma of bioactive compounds (phenolics, flavonoids alkaloids, ellagic acid, punicalagin, anthocyanins, and tannins) with antioxidant [2], anti-inflammatory [3], antimicrobial [4], anticancer [5], anti-cardiovascular [6–8], and anti-infective [9] activities. As claimed by in vitro assays, commercial pomegranate juice has three-fold the antioxidant activity of red wine and green tea. In pomegranate anthocyanins predominate over tannins, explaining its high reducing activity. Cyanidin-3,5-*O*-diglucoside and pelargonidin-3,5-*O*-diglucoside are the most representative anthocyanins in the different genotypes of pomegranate. Due to its great contents of different phytochemicals with health-promoting effects [10,11], pomegranate fruit is considered the king of the super fruits group [12], and its extracts are also used by the pharmaceutical industry for creating supplements in capsules [13]. Pomegranate cultivation covers, worldwide, about 300,000 ha, with a production of 3 million tons, of which more than 76% is located in India, Iran, China, Turkey, and the USA. The 500 cultivars of pomegranate that have been identified have different physical–chemical characteristics and produce fruits that differ in the amount and types of bioactive compounds [14,15]. Fruits are of the best quality at a temperature of 38 ◦C under a dry climate; thus, the Mediterranean basin has the appropriate climatic conditions, representing an ideal area for high production of good-quality pomegranate fruits.

**Citation:** Marra, F.; Petrovicova, B.; Canino, F.; Maffia, A.; Mallamaci, C.; Muscolo, A. Pomegranate Wastes Are Rich in Bioactive Compounds with Potential Benefit on Human Health. *Molecules* **2022**, *27*, 5555. https:// doi.org/10.3390/molecules27175555

Academic Editor: Nour Eddine Es-Safi

Received: 4 August 2022 Accepted: 24 August 2022 Published: 29 August 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

Mediterranean pomegranates are mainly based on local cultivars, and their composition can differ from those of Eastern varieties, displaying a large variety of physical–chemical traits and distinct flavor profiles. Wonderful is the most widespread commercial pomegranate cultivar planted in Mediterranean countries and represents the industry standard variety. In the last few decades, around the world, there has been an increasing interest in the use of pomegranate and its parts, justified by an increasing demand from health care consumers and the pharmaceutical and cosmetic industries [13]. Generally, the edible part of pomegranate is directly consumed as food, or used for the preparation of juices, canned beverages, jams, and for the flavoring and coloring of drinks; conversely, pomegranate peel (approximatively 26–30% of the total fruit weight), which currently still represents a waste to be disposed of, is attracting the attention of the scientific community for its high content of phytochemicals that allow it to individuate as a new source of bioactive compounds, such as flavonoids, phenolic acids, and tannins with well-ascertained antioxidant capacity [16–18]. It has been reported that pomegranate by-products, and punicalagins in particular, decrease the level of fats in the blood and have anticancer, antiviral, and anti-inflammatory properties [15,19–21]. The scientific community was previously focused on the chemical characterization and health effects of pomegranate as a fruit or juice and only few studies were recently focused on the amount and composition of the bioactive compounds present in the pomegranate peel, which usually are a mixture, the synergistic effect of which can often cause different physiological responses acting on different organ targets contemporarily.

Based on the above considerations, the aim of the present study was to analyze the pomegranate peel composition of the variety Wonderful cultivated in Southern Italy and treated with an innovative system of dry concentration by the Gioia Succhi food industry. The specific aim was to verify if the growth area, cultivar type, and dry procedure influencing the chemical composition of the peels in terms of valuable bioactive compounds with beneficial effects in the prevention of numerous diseases or metabolic disorders. A comparison between the peel chemical composition of Wonderful cultivated in Southern Italy and treated with a spray-dry system and the peel chemical composition of freezedried Wonderful cultivated in Southern Italy, freeze-dried Wonderful cultivated in South Africa [15,22], and freeze-dried Kullu and Himachal [23,24] cultivated in India and already used in a pharmaceutical scope was carried out.
