This work is part of The FrureFinery project (2024-2026), founded by the European Union’s PR FESR 2021-2027, which aims to promote circular economy practices within the Emilia-Romagna agri-food sector by developing sustainable strategies to convert fruit waste into high-value resources [1]. Fruit processing generates a significant amount of leftovers and organic waste, which still contain valuable compounds such as lipids, fibers, and other bioactive molecules (including polyphenols and antioxidants). Recovery of these compounds from agri-food by-products offers promising significant potential for applications in food, oleochemical, cosmetic and pharmaceutical industries. Agricultural and industrial residues are attractive sources of antioxidants and dietary fiber, besides reducing environmental pollution in a circular economy framework [1].
This study aimed to assesses the polyphenolic content and antioxidant potential of selected fruit by-products (apple, watermelon, melon, avocado, coconut, kiwi, pineapple, pomegranate, mango, ginger). The amount of polyphenols in fruit waste was determined using the Folin-Ciocalteu method, and antioxidant activity was assessed using the 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Subsequently, the phenolic profile was investigated using untargeted UHPLC-HRMS analysis. Chromatographic separations were performed in untargeted mode in Data Dependent Acquisition (DDA), and the large datasets were further processed using Compound Discoverer 3.3 software followed by statistical evaluation.
Hierarchical clustering showed three groups: i) polyphenol-rich (pomegranate, avocado, coconut, mango), ii) intermediate (apple, kiwi), and iii) polyphenol-poor (melon, ginger, watermelon, pineapple). Polyphenol-rich fruits, such as pomegranate and avocado, can be exploited to support dietary strategies for oxidative stress management and the development of functional foods or natural antioxidants. In contrast, polyphenol-poor fruits (e.g., watermelon, melon) may serve as potential carriers or diluents in formulations where a milder phytochemical profile. This work clearly highlights the potential of fruit leftovers as valuable resources, offering them a second life through sustainable reuse.
Ibrahim, U. K., et al. "Local fruit wastes as a potential source of natural antioxidant: an overview." IOP conference series: materials science and engineering. Vol. 206. No. 1. IOP Publishing, 2017. DOI: 10.1088/1757-899X/206/1/012040.