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<dc:title>Onion (Allium cepa L.) Skin Waste Valorization: Unveiling the Phenolic Profile and Biological Potential for the Creation of Bioactive Agents through Subcritical Water Extraction</dc:title>
<dc:creator>Trigueros Andrés, Ester</dc:creator>
<dc:creator>Benito Román, Oscar</dc:creator>
<dc:creator>Oliveira, Andreia P.</dc:creator>
<dc:creator>Videira, Romeu A.</dc:creator>
<dc:creator>Andrade, Paula B.</dc:creator>
<dc:creator>Sanz Díez, Mª Teresa</dc:creator>
<dc:creator>Beltrán Calvo, Sagrario</dc:creator>
<dc:subject>Hydrothermal treatment</dc:subject>
<dc:subject>Onion waste</dc:subject>
<dc:subject>Polyphenols</dc:subject>
<dc:subject>Quercetin</dc:subject>
<dc:subject>Antioxidant activity</dc:subject>
<dc:subject>Antidiabetic potential</dc:subject>
<dc:description>Onion skin waste (OSW), the primary non-edible byproduct from onion processing, offers a renewable source of bioactive compounds. This study aims to valorize OSW through subcritical water extraction (SWE), aligning with a circular economy and biorefinery principles. SWE was carried out at 145 °C and 50 bar for 50 min in a discontinuous reactor, producing a phenolic-rich extract (32.3 ± 2.6 mg/g) dominated by protocatechuic acid (20.3 ± 2.5 mg/g), quercetin-4′-O-glucoside (7.5 ± 0.2 mg/g), and quercetin (3.2 ± 0.6 mg/g). Additionally, the extract contains sugars (207.1 ± 20.3 mg sucrose-Eq/g), proteins (22.8 ± 1.6 mg BSA-Eq/g), and free amino acids (20.4 ± 1.2 mg arginine-Eq/g). Its phenolic richness determines its scavenging activity against ●NO and O2●− radicals and its α-glucosidase and aldose-reductase inhibition without affecting α-amylase. Notably, the extract demonstrates significant α-glucosidase inhibition (IC50 = 75.6 ± 43.5 µg/mL), surpassing acarbose (IC50 = 129.5 ± 1.0 µg/mL) in both pure enzyme and cell culture tests without showing cytotoxicity to AGS, HepG2, and Caco-2 human cell lines. The extract’s bioactivity and nutritional content make it suitable for developing antioxidant and antidiabetic nutraceutical/food components, highlighting SWE’s potential for OSW valorization without using organic solvents.</dc:description>
<dc:date>2024-03-08T08:01:31Z</dc:date>
<dc:date>2024-03-08T08:01:31Z</dc:date>
<dc:date>2024-02</dc:date>
<dc:type>info:eu-repo/semantics/article</dc:type>
<dc:identifier>2076-3921</dc:identifier>
<dc:identifier>http://hdl.handle.net/10259/8778</dc:identifier>
<dc:identifier>10.3390/antiox13020205</dc:identifier>
<dc:identifier>2076-3921</dc:identifier>
<dc:language>eng</dc:language>
<dc:relation>Antioxidants. 2024, V. 13, n. 2, 205</dc:relation>
<dc:relation>https://doi.org/10.3390/antiox13020205</dc:relation>
<dc:relation>info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-116716RJ-I00/ES/TECNOLOGIAS DE FLUIDOS PRESURIZADOS PARA LA VALORIZACION DE SUBPRODUCTOS DE LA INDUSTRIA AGROALIMENTARIA: RECUPERACION DE PECTINA Y OTROS COMPUESTOS BIOACTIVOS DE ALTO VALOR/</dc:relation>
<dc:rights>http://creativecommons.org/licenses/by/4.0/</dc:rights>
<dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
<dc:rights>Atribución 4.0 Internacional</dc:rights>
<dc:publisher>MDPI</dc:publisher>
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