Onion (Allium cepa L.) Skin: A Rich Resource of Biomolecules for the Sustainable Production of Colored Biofunctional Textiles

Abstract

The aqueous extract of dry onion skin waste from the ‘Dorata di Parma’ cultivar was tested as a new source of biomolecules for the production of colored and biofunctional wool yarns, through environmentally friendly dyeing procedures. Specific attention was paid to the antioxidant and UV protection properties of the resulting textiles. On the basis of spectrophotometric and mass spectrometry analyses, the obtained deep red-brown color was assigned to quercetin and its glycoside derivatives. The Folin–Ciocalteu method revealed good phenol uptakes on the wool fiber (higher than 27% for the textile after the first dyeing cycle), with respect to the original total content estimated in the water extract (78.50 ± 2.49 mg equivalent gallic acid/g onion skin). The manufactured materials showed remarkable antioxidant activity and ability to protect human skin against lipid peroxidation following UV radiation: 7.65 ± 1.43 (FRAP assay) and 13.60 (ORAC assay) mg equivalent trolox/g textile; lipid peroxidation inhibition up to 89.37%. This photoprotective and antioxidant activity were therefore ascribed to the polyphenol pool contained in the outer dried gold skins of onion. It is worth noting that citofluorimetric analysis demonstrated that the aqueous extract does not have a significative influence on cell viability, neither is capable of inducing a proapoptotic effect.

HOPS/TMUB1 retains p53 in the cytoplasm and sustains p53‐dependent mitochondrial apoptosis

“…The percentage of PerCP-eFluor 710 positive apoptotic cells was determined by flow cytometry [53,54]. The cells, after treatment, were collected by centrifugation, washed with PBS, stained with Fixable Viability Dye eFluor â 780 (eBioscience, CA) for 30 min and then washed with PBS and Flow Cytometry Staining Buffer.…”

Low-Molecular-Weight Phenols Recovery by Eco-Friendly Extraction from Quercus Spp. Wastes: An Analytical and Biomass-Sustainability Evaluation

“…Phenolic compounds such as gallic acid, catechin, and epicatechin are notoriously endowed with antioxidants, astringents, and antimicrobial activity. Therefore, such species are subject of increasing interest in various fields such as pharmaceuticals, leather tanning, cosmetics, and the food industry [7][8][9][10][11]. Low-molecular-weight hydroxybenzoic acids and some of their derivatives can be obtained from wood extractives and via induced lignin degradation [12,13].…”

Incorporation of yellow onion peel extract into the funoran‐based biodegradable films as an antioxidant packaging material

“…This suggested that YOPE contains considerable amount of quercetin as a major polyphenol. Other studies also reported the presence of quercetin in YOPE (Jeong et al, 2009;Pucciarini et al, 2019). Additionally, the TPC and TFC of YOPE in the films containing YOPE were determined (Table 3).…”