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oai:riubu.ubu.es:10259/60922023-11-30T23:42:07Zcom_10259_4244com_10259_5086com_10259_2604col_10259_4245

Benito Román, Oscar Blanco Alcalde, Beatriz Sanz Díez, Mª Teresa Beltrán Calvo, Sagrario 2021-11-04T09:49:05Z 2021-11-04T09:49:05Z 2021-11 0960-3085 http://hdl.handle.net/10259/6092 10.1016/j.fbp.2021.09.005 In this work, the intensification of the extraction of flavonoids from dry onion skin wastes (DOSW) by Ultrasound Assisted Extraction (UAE) was investigated. Conventional stirred tank extraction was used to find the optimal temperature (37 °C) and solvent (ethanol 70%, v/v), providing 20.7 ± 0.4 mg QE/g DOSW after 1 h. In the UAE process, the amplitude of oscillation and the solvent-to-solid ratio were key parameters to control the specific energy used. Energies above 10 kJ/g OSW did not increase the extraction yield (maximum flavonoids content was 23.9 ± 0.2 mg QE/g DOSW), which could be obtained using amplitudes of 40%, high solvent-to-solid ratios (30 mL/g DOSW) and extraction times below 5 min. Although both extraction techniques provided similar profiles of phenolic compounds, being quercetin and quercetin-4′-O-glucoside the main flavonoids (7.4 mg/g DOSW and 10.4 mg/g DOSW, respectively), UAE increased the productivity up to 11.6 mg QE/(g DOSW·min), seven times higher than conventional extraction. The extraction kinetics was modeled and studied. The optimum extract was freeze-dried resulting in a solid powder rich in flavonoids (21%) which kept 90% of the antioxidant activity after 180 days of storage at temperatures below 4 °C. Junta de Castilla y León (JCyL) and the European Regional Development Fund (ERDF) [grant numbers BU301P18 and BU050P20] and the Agencia Estatal de Investigación [grant number PID2019-104950RB-I00/AEI/10.13039/501100011033 and PID2020-116716RJ-I00]. OBR’s postdoctoral contract through project BU301P18 is gratefully acknowledged. To JCyL and European Social Fund (ESF) for the contract of D. Benito-Bedoya and D. M. Aymara-Caiza through the YEI program, who participated in this work as technicians. application/pdf eng Elsevier Food and Bioproducts Processing. 2021, V. 130, p. 92-105 https://doi.org/10.1016/j.fbp.2021.09.005 Attribution-NonCommercial-NoDerivatives 4.0 Internacional http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess Onion Extraction Ultrasounds Quercetin Flavonoids Process intensification Ingeniería química Alimentos Chemical engineering Food Freeze-dried extract from onion (Allium cepa cv. Horcal) skin wastes: Extraction intensification and flavonoids identification info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion