Efficient preparation and decolorization of water-soluble walnut meal protein: Characterization of structure and...

Walnut meal protein development is limited by low solubility, low recovery rate and intense pigment. This study optimized the walnut meal protein extraction process. Under optimal preparation conditions, the recovery rate of walnut meal protein (G-WP) reached 78.92 ± 0.30% (only 6.16 ± 0.31% at room temperature), and the solubility of G-WP exceeded 98%. Then, decolorization of G-WP using D392 macroporous resin yielded DG-WP, with a decolorization rate of 67.82 ± 0.07%. G-WP and DG-WP exhibited increased β-turn and random coil content. The surface hydrophobicity of G-WP and DG-WP was improved by 2.04 and 2.14 times, respectively. The combination of the above structural characterization, free sulfhydryl content, and microstructures revealed that the decolorization treatment did not induce significant structural differences between G-WP and DG-WP. And they demonstrated superior functional properties with no significant differences. This study provides a novel approach for the efficient preparation of decolorized water-soluble walnut meal protein.