Green extraction of isoflavones from okara using subcritical water: Kinetics, optimization, and comparison with other water-based sustainable methods
2025
Barea Gómez, Pedro | Illera Gigante, Alba Ester | Melgosa Gómez, Rodrigo | Benito Román, Oscar | Candela Gil, Helena | Beltrán Calvo, Sagrario | Sanz Díez, Mª Teresa
Water has been explored as a green extraction agent for isoflavone extraction from okara. First, subcritical water (subW) was explored using two different okaras: (1) washed and dried (OKW) and (2) non-pretreated (OKC). Genistein family was the most abundant, with very low quantities in the glycitein family. Kinetic data revealed interconversion of malonyl-glycosides to β-glycosides in subW, with increasing degradation rate constants for all isoflavones with temperature. A maximum of 1229 μg isoflavone/g of dried okara was obtained at 120 °C after 30 min for OKC. Microwave (MAE) and ultrasound (UAE) technologies achieved 72.8 % and 75.4 %, of the yield of subW. Productivity at the maximum was of 41.0, 82.5 and 92.8 μg isoflavone/g dry okara min for subW, MAE, UAE. However, higher fraction of the more bioavailable forms β-glycoside + aglycone was obtained by subW.
Show more [+] Less [-]This work was supported by the Agencia Estatal de Investigación [grant numbers PID2022-136385OB-I00, PDC2022–133443-I00, TED2021-129311B-I00], Junta de Castilla y León (JCyL), and European Regional Development Fund (ERDF) [grant number BU027P23]. A. E. Illera postdoctoral contract was funded by BU027P23. P. Barea and H. Candela pre-doctoral contracts are funded by JCyL and the European Social Fund (ESF) [ORDEN EDU/1868/2022, ORDEN EDU/1009/2024, respectively]. The R Melgosa contract was funded by a Beatriz Galindo Research Fellowship [BG20/00182].
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