The chestnut tree (Castanea sativa, Mill.) is a widespread plant in Europe whose fruits and wood has a relevant economic impact. Chestnut wood (CW) is rich in high-value compounds that exhibit various biological activities, such as antioxidant as well as anticarcinogenic and antimicrobial properties. These metabolites can be mainly divided into monomeric polyphenols and tannins. In this piece of work, we investigated a sustainable protocol to isolate enriched fractions of the above-mentioned compounds from CW residues. Specifically, a sequential extraction protocol, using subcritical water, was used as a pre-fractionation step, recovering approximately 88% of tannins and 40% of monomeric polyphenols in the first and second steps, respectively. The optimized protocol was also tested at pre-industrial levels, treating up to 13.5 kg CW and 160 L of solution with encouraging results. Ultra- and nanofiltrations were used to further enrich the recovered fractions, achieving more than 98% of the tannin content in the heavy fraction, whilst the removed permeate achieved up to 752.71 mg GAE/g_ext after the concentration (75.3%). Samples were characterized by means of total phenolic content (TPC), antioxidant activity (DPPH· and ABTS·), and tannin composition (hydrolysable and condensed). In addition, LC-MS-DAD was used for semiqualitative purposes to detect vescalagin/castalagin and vescalin/castalin, as well as gallic acid and ellagic acid. The developed valorization protocol allows the efficient fractionation and recovery of the major polyphenolic components of CW with a sustainable approach that also evaluates pre-industrial scaling-up.

In the context of a circular economy, this study explores the valorization of blueberry pomace (BP) as a source of bioactive compounds using sustainable extraction methods. Microwave-assisted extraction (MAE) and microwave-assisted subcritical water extraction (MASWE) were employed to obtain two distinct fractions: MAE 1° and MASWE 2°. The first extract, MAE 1°, obtained at 80 °C, had a high total anthocyanin content (21.96 mg_Cya-3-glu/g_extract), making it suitable as a natural pigment. Additionally, MAE 1° exhibited significant enzyme inhibition, particularly against α-amylase and β-glucosidase, suggesting potential anti-diabetic and anti-viral applications. The second extract, MASWE 2°, obtained at 150 °C, contained a higher total phenolic content (211.73 mg_GAE/g_extract) and demonstrated stronger antioxidant activity. MASWE 2° showed greater inhibition of acetylcholinesterase and tyrosinase, indicating its potential for use in Alzheimer’s treatment, skincare, or as a food preservative. MASWE 2° exhibited cytotoxicity against HeLa cells and effectively mitigated H₂O₂-induced oxidative stress in HaCat cells, with MAE 1° showing similar but less pronounced effects. A tested formulation combining MAE 1° and MASWE 2° extracts in a 3:2 ratio effectively enhanced anthocyanin stability, demonstrating its potential as a heat-stable pigment. The extract characteristics were compared with a conventional method (MeOH-HCl in reflux condition), and the protocol’s sustainability was assessed using several green metric tools, which provided insights into its environmental impact and efficiency.

The disposal of agri‐food biomass waste, such as chestnut wood waste (CWW), poses significant environmental and industrial challenges, contributing to resource depletion and waste accumulation. The development of sustainable strategies for biomass valorization is crucial for reducing waste and promoting a circular economy. In this study, microwave‐assisted subcritical water extraction (MASWE) is investigated as an efficient and environmentally friendly method for the extraction of high‐value bioactive compounds such as condensed tannins (CTs), hydrolyzable tannins (HTs), and low‐weight polyphenols from CWW. The extraction process is followed by sequential membrane filtration and resin purification, adhering to green extraction principles to maximize yield and avoid water wastage. Furthermore, tannins are utilized in the synthesis of biopolymers, offering a promising strategy for developing novel materials with tailored properties. Their antimicrobial activity and enzyme‐inhibiting properties improve biopolymer formulations, unlocking diverse applications in sustainable materials. This approach through advanced extraction and fractionation protocols not only enhances biomass valorization—aligning with the circular economy in agri‐food waste management—but also supports advancements in green technology and the development of eco‐friendly materials.

Introducing SIX Score, an open-access metric that embeds green extraction principles into a standardized, quantitative sustainability assessment for extraction processes.

Curcuminoids from Curcuma longa L. (curcumin, demethoxycurcumin, bisdemethoxycurcumin) are attractive bioactives yet constrained by low water solubility and chemical instability. Herein, we introduce a Supramolecular Deep Eutectic Solvent (SupraDES) as a “Janus” green platform, combining extraction and stabilization with a subsequent solvent-to-material strategy. Eight NaDES/SupraDES formulations based on choline chloride (ChCl) or betaine with glycerol (Gly) or citric acid (CitA), with/without β-cyclodextrin (βCD), were assessed. The extinction coefficients of the most promising solvents were extrapolated at 425 nm for the UV–vis quantification of curcuminoids, to determine extraction performance. The SupraDES ChCl:Gly:βCD gave the best performance during the first solvent screening, improving at the same time the bioactive stability (after 30-day, 47.5% loss vs. 62.8% of ChCl:Gly alone). Subsequent microwave-assisted extraction (MAE) optimization identified 80 °C as the optimal process temperature, with near-equilibrium reached within 15 min (3139.4 µgCurc/gEXT). Peleg modelling (R² = 0.997) indicated a fast extraction rate and limited benefit from longer residence times. Finally, the curcuminoid-loaded SupraDES was incorporated into polyvinyl alcohol (PVA) networks crosslinked with CitA and 2,5-bis(hydroxymethyl)furan (BHMF); thermal analysis confirmed the formation of a stable crosslinked structure. To the best of our knowledge, this is the first report of a βCD-based SupraDES acting as a Janus platform that couples supramolecular extraction of lipophilic bioactives with their direct incorporation into bio-based polymeric materials, exemplifying an integrated green chemistry approach aligned with circular bioeconomy principles.