{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,14]],"date-time":"2026-07-14T17:14:01Z","timestamp":1784049241270,"version":"3.55.0"},"reference-count":41,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2025,8,29]],"date-time":"2025-08-29T00:00:00Z","timestamp":1756425600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Scientific Research Deanship at the University of Ha\u2019il\u2014Saudi Arabia","award":["RG-24159"],"award-info":[{"award-number":["RG-24159"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Grape stems are an abundant by-product of winemaking and a promising source of phenolic antioxidants representing an underutilized biomass within the circular economy. Seven Vitis vinifera L. cultivars were analysed by HPLC DAD, with Merlot (Me), Cabernet Sauvignon (CS) and Italian Riesling (IR) identified as the richest sources. This comparative screening provided the basis for a multi-index optimization of extraction. A 23 full factorial design (ethanol 30\u201360% v\/v; 30\u201380 min; 25\u201365 \u00b0C) was used for optimization. The optimal green conditions\u201460% ethanol, 80 min, 65 \u00b0C\u2014yielded 1.860 mg\/g CA, 1.098 mg\/g Q-gluc and 0.409 mg\/g Q-glc, with the Merlot stems showing the highest extraction efficiency and Merlot consistently outperforming the other varieties. Kinetic modeling using an unsteady state diffusion model showed excellent agreement (R2 \u2248 0.99, RMS &lt; 2%), suggesting a leaching-diffusion mechanism. The thermodynamic parameters confirmed an endothermic, spontaneous and irreversible process with \u0394H\u00b0 between 19.5 and 36.6 kJ\/mol, \u0394S\u00b0 between 69.1 and 131.6 J\/molK and \u0394G\u00b0 between \u22121.1 and \u22129.2 kJ\/mol, depending on the compound and grape stem variety. This study shows that grape stems can be efficiently utilised as a sustainable source of phenolic antioxidants, with potential applications in the production of functional foods and dietary supplements. This integration highlights the novelty of the study and supports the valorization of grape stems in the framework of sustainability and the circular economy.<\/jats:p>","DOI":"10.3390\/molecules30173546","type":"journal-article","created":{"date-parts":[[2025,8,29]],"date-time":"2025-08-29T16:18:15Z","timestamp":1756484295000},"page":"3546","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Targeted Recovery of Phenolic Antioxidants from Grape Stems: A Sequential Approach"],"prefix":"10.3390","volume":"30","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2180-8303","authenticated-orcid":false,"given":"Violeta","family":"Jevtovic","sequence":"first","affiliation":[{"name":"Chemistry Department, College of Science, University of Ha\u2019il, Ha\u2019il 81451, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2971-7593","authenticated-orcid":false,"given":"Khulood Fahad Saud","family":"Alabbosh","sequence":"additional","affiliation":[{"name":"Biology Department, College of Science, University of Ha\u2019il, Ha\u2019il 81451, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6981-1632","authenticated-orcid":false,"given":"Zoran","family":"Pr\u017ei\u0107","sequence":"additional","affiliation":[{"name":"Institute of Horticulture, Faculty of Agriculture, University of Belgrade, 11080 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9351-331X","authenticated-orcid":false,"given":"Jelena","family":"Nikoli\u0107","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science and Mathematics, University of Ni\u0161, 18000 Ni\u0161, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Reem","family":"Ali Alyami","sequence":"additional","affiliation":[{"name":"Chemistry Department, College of Science, University of Ha\u2019il, Ha\u2019il 81451, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-0024-4459","authenticated-orcid":false,"given":"Maha Raghyan","family":"Alshammari","sequence":"additional","affiliation":[{"name":"Chemistry Department, College of Science, University of Ha\u2019il, Ha\u2019il 81451, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Badriah","family":"Alshammari","sequence":"additional","affiliation":[{"name":"Chemistry Department, College of Science, University of Ha\u2019il, Ha\u2019il 81451, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7921-8576","authenticated-orcid":false,"given":"Violeta","family":"Rakic","sequence":"additional","affiliation":[{"name":"Department of Agriculture and Food Technology Studies Prokuplje, Toplica Academy of Applied Studies, 18400 Prokuplje, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1176-7103","authenticated-orcid":false,"given":"Odeh A. O.","family":"Alshammari","sequence":"additional","affiliation":[{"name":"Chemistry Department, College of Science, University of Ha\u2019il, Ha\u2019il 81451, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Milan","family":"Miti\u0107","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science and Mathematics, University of Ni\u0161, 18000 Ni\u0161, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Jesus, M., Roman\u00ed, A., Mata, F., and Domingues, L. (2022). Current Options in the Valorisation of Vine Pruning Residue for the Production of Biofuels, Biopolymers, Antioxidants, and Bio-Composites following the Concept of Biorefinery: A Review. 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