2024-03-29T08:48:48Zhttps://riubu.ubu.es/oai/requestoai:riubu.ubu.es:10259/60882022-11-08T13:31:41Zcom_10259_4244com_10259_5086com_10259_2604col_10259_4245
Subcritical water extraction of phenolic compounds from onion skin wastes (Allium cepa cv. horcal): effect of temperature and solvent properties
Benito Román, Oscar
Blanco Alcalde, Beatriz
Sanz Díez, Mª Teresa
Beltrán Calvo, Sagrario
Onion
Extraction
Subcritical water
Quercetin
Polarity
Valorization
Ingeniería química
Chemical engineering
The valorization of onion skin wastes (OSW) through the extraction, identification,
and quantification of phenolic compounds was studied in this work, using subcritical water in a
semicontinuous extractor (2.5 mL/min; 105–180 C; 5 MPa). The extraction of flavonoids resulted to
be fast (<30 min) and temperature sensitive (maximum at 145 C; total flavonoids, 27.4 0.9 mg/g
dry OSW (DOSW)). The experimental results were fitted to theWeibull model. The influence of the
solvent properties on the flavonoids quantification was found to be critical. A precipitate was formed
once the extracts cooled down. If removed, a significant fraction of the high temperature extracted
flavonoids (as much as 71%, at 180 C) was lost. Such a condition a ected especially those compounds
that show extremely low solubility in water at room temperature, whereas quercetin glycosylated
derivatives were less a ected by the polarity change of the medium induced by the temperature
change. It was demonstrated that it is necessary to re-dissolve the subcritical water extracts by
the addition of ethanol, which led to a medium with a polarity equivalent to that obtained with
water at high temperature. At 145 C, quercetin (15.4 0.4 mg/g DOSW) and quercetin-40-glucoside
(8.4 0.1 mg/g DOSW) accounted for the 90% of the total flavonoids identified. By recovering high
added value bioactive compounds from OSW the principles of circular economy were fulfilled,
providing a new use for this agricultural waste.
Junta de Castilla y León (JCyL) and the European Regional Development
Fund (ERDF)) through projects BU301P18 and BU050P20, and by the Agencia Estatal de Investigación through
grant number PID2019-104950RB-I00/AEI/10.13039/501100011033. OBR’s postdoctoral contract was funded by
JCyL and EDRF through project BU301P18.
2021-11-04T09:22:56Z
2021-11-04T09:22:56Z
2020-12
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
2076-3921
http://hdl.handle.net/10259/6088
10.3390/antiox9121233
eng
Antioxidants. 2020, V. 9, n. 12, 1233
https://doi.org/10.3390/antiox9121233
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2019-104950RB-I00/ES/VALORIZACION DE SUBPRODUCTOS MARINOS MEDIANTE TECNOLOGIAS DE FLUIDOS SUB- Y SUPERCRITICOS PARA LA OBTENCION DE BIOCOMPUESTOS VALIOSOS
info:eu-repo/grantAgreement/Junta de Castilla y León//BU301P18
info:eu-repo/grantAgreement/Junta de Castilla y León//BU050P20
Atribución 4.0 Internacional
http://creativecommons.org/licenses/by/4.0/
info:eu-repo/semantics/openAccess
application/pdf
MDPI