Engineering soy protein/konjac glucomannan double network hydrogels with low voltage-electric field: Anisotropic structure and properties

Anisotropic hybrid hydrogels were fabricated from soy protein isolate (SPI) and konjac glucomannan (KGM) by applying an electric field of 2.98  V /cm. These hydrogels formed a double network primarily stabilized through disulfide bonds, hydrophobic interactions, and hydrogen bonds, contributing 38.15 % to 46.16 %, 15.07 % to 18.38 %, and 3.06 % to 13.49 %, respectively, depending on the KGM levels. The resulting hydrogels displayed a highly organized three-dimensional architecture with filamentous KGM chains interwoven within the chains of SPI aggregates. As KGM content in hydrogels increased from 1.0 % to 2.5 %, the pore sizes of hydrogels decreased and lamellar structure became denser, the apparent viscosity and modulus of the blend solutions increased, their hardness declined from 76.62 g to 41.43 g transversely and from 60.03 g to 34.35 g longitudinally. Similarly, chewiness dropped from 121.16 g·s to 62.28 g·s transversely and from 83.21 g·s to 58.39 g·s longitudinally. In addition to anisotropic structure and texture, the hydrogels demonstrated excellent moisture retention stability (89.85–91.07 %) and robust anti-swelling properties, with water-holding stability improving from 69.64 % to 90.12 % as KGM content increased. These results provide valuable insights into customizing novel structures and enhancing the physicochemical properties of food hydrogels using sustainable materials and approaches.