RT info:eu-repo/semantics/article
T1 Cascade Valorization of Okara by Subcritical Water Hydrolysis: Assessment of Protein and Amino Acid Profile in Batch and Semi-Continuous Systems
A1 Barea Gómez, Pedro
A1 Illera Gigante, Alba Ester
A1 Candela Gil, Helena
A1 Melgosa Gómez, Rodrigo
A1 Benito Román, Oscar
A1 Sanz Díez, Mª Teresa
K1 Subcritical water
K1 Okara
K1 Isoflavones
K1 Protein
K1 Amino acid profile
K1 Scaling-up process
K1 Productos de la soja
K1 Soybean products
K1 Proteínas
K1 Proteins
AB This study assesses subcritical water hydrolysis (SWH) as a sustainable approach for protein recovery from okara, following isoflavone valorization. The initial extract, obtained at 120 °C, contained over 1200 µg of isoflavones per gram of dry okara. The solid residue underwent a second protein extraction step in both batch and semi-continuous modes. The batch extraction was conducted at 180 °C for 3 h at 5 MPa in a 0.5 L reactor. Under these conditions, total amino acid recovery reached 81 ± 3% (12.6 g/L), with 20 ± 1% of free amino acids, mainly glutamic acid, and a favorable profile of essential amino acids. These results were comparable to protein extraction from untreated okara, indicating that the prior isoflavone extraction did not hinder protein hydrolysis, but rather contributed positively within the cascade framework. Hydrolysis was also performed in a semi-continuous mode in a 2.3 L reactor, with a residence time of 2.75 min, in a two-stage temperature process (180 °C and 270 °C). The second stage yielded a significantly higher extraction than the first one, achieving a total 70.4% protein recovery (1.22 g/L) with 10% of free amino acids, with glutamic acid as the dominant one. Carbohydrate analysis revealed high hydrolysis yields for galactans, arabinans, and xylans, but these exhibited lower thermal stability compared to proteins. Okara emerges as a promising by-product for a bio-cascade process, combining a mild first stage for isoflavone extraction with a more severe second stage for protein extraction/hydrolysis.
PB Springer
SN 1935-5130
YR 2026
FD 2026-05
LK https://hdl.handle.net/10259/11954
UL https://hdl.handle.net/10259/11954
LA eng
NO Open access funding provided by FEDER European Funds and the Junta de Castilla y León under the Research and Innovation Strategy for Smart Specialization (RIS3) of Castilla y León 2021-2027. This work was supported by the Junta de Castilla y León (JCyL) and the European Regional Development Fund (ERDF) [grant number BU027P23]. P. Barea and H. Candela pre-doctoral contracts are funded by JCyL and the European Social Fund (ESF) [ORDEN EDU/1868/2022 and ORDEN EDU/1009/2024, respectively].
DS Repositorio Institucional de la Universidad de Burgos
RD 27-jul-2026