Valorization of coffee industry wastes: Comprehensive physicochemical characterization of coffee silverskin and multipurpose recycling applications. (10th October 2022)

• Record Type: Journal Article
• Authors: Nolasco, Agata; Squillante, Jonathan; Velotto, Salvatore; D'Auria, Giovanni; Ferranti, Pasquale; Mamone, Gianfranco; Errico, Maria Emanuela; Avolio, Roberto; Castaldo, Rachele; Cirillo, Teresa; Esposito, Francesco
• Is Part Of: Journal of cleaner production. Volume 370(2022)
• Publication Date: 2022-10-10
• Subjects: Silverskin -- Coffee by-products -- Recycling -- Integument -- Agro-food waste; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2022.133520
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Every year, the coffee supply chain produces tons of waste materials from the processing of the coffee bean. Coffee silverskin (CS) is the only waste product from the coffee bean roasting phases but as roasting is a key step in obtaining the coffee beverage, there are tons of CS collected and thrown away by coffee roasting industries. This study is based on the characterization of this integument, with a view to its use in nutritional, nutraceutical and industrial fields. From the results obtained, silverskin can be used in the food sector for its nutritional profile with a good amount of protein (18.9%) and total dietary fiber (34.7%) andits low-fat content (3.0%). Food safety was also determined by evaluating the low levels of contaminants such as ochratoxin A (OTA) and acrylamide (AA), with values < 0.1 mg/kg and <0.02 mg/kg respectively. Low concentrations of heavy metals and polycyclic aromatic hydrocarbons (PAHs) completed the safety-related overview in terms of CS contamination. For the nutraceutical aspect, an in-silico analysis of the peptide fraction was proper to evaluate the presence of angiotensin-converting enzyme (ACE) inhibitory peptides, antioxidants and dipeptidyl peptidase (DPP) IV inhibitors with promising uses for the treatment of diabetes and its side effects. Finally, through morphological-structural characterization of CS, the main constituents such as lignin, cellulose and hemicellulose were identified spectrally by Fourier transform infrared spectroscopy (FT-IR) and solid-state CP/MAS 13 C NMR spectroscopy. The CS thermostability was monitored by thermogravimetric (TG) analysis, and the tegument surface was evaluated by Scanning Electron Microscopy (SEM) and volumetric nitrogen adsorption analysis. This information provides a broader view of the possible uses of CS as a filler for biocomposite materials. Therefore, from the perspective of recovering waste materials from food supply chains, coffee silverskin could be a good product to focus on. Highlights: Tons of coffee silverskin (CS) are produced each year by coffee roasting plants. CS generates handling problems and disposal costs. Physico-chemical characteristics make it suitable for its use in the food sector. Its peptidic fraction might show inhibitory activities toward key enzymes. CS could be suitable for applications as eco-friendly product.