Effects of Konjac Glucomannan and Chitin Nanowhiskers on Structural and Physical Properties of Soy Protein Isolate Composite Hydrogels

Soybean protein isolates (SPIs) have been widely studied because of their excellent gel-forming properties. However, their unstable gel structures and poor strength limit their applications in the food industry. To address this, konjac glucomannan (KGM) and oxidized chitin nanocrystals (O-ChNCs) were introduced into SPI-based hydrogels to enhance their mechanical properties. The present study investigated the effects of incorporating KGM and O-ChNCs on the physical properties and microstructure of SPI hydrogels, as well as the possible underlying mechanisms. The rheological behavior test of the solution demonstrated that the viscoelastic properties of the sol were enhanced upon incorporating O-ChNCs and KGM. Scanning electron microscopy showed highly compact and uniformly distributed SPI hydrogels with the addition of O-ChNCs and KGM. Gel strength and textural property tests showed that the gel strength and gel hardness of SPI hydrogels with the addition of O-ChNCs and KGM were 102.57 ± 1.91 g/cm² and 545.29 ± 6.84 g. O-ChNCs effectively filled the SPI hydrogel network, while KGM enhanced physical entanglement between SPI molecular chains and formed intermolecular hydrogen bonds. Therefore, this study provides an important basis for the introduction of SPI-based hydrogels in the biomedical and food industries.