Increased consumption of plant-based foods and better utilization of by-products could reduce the environmental impact of food consumption. In this study, IDF-SA-PPI ternary composite gels were prepared by a pH-controlled method by adding IDF (insoluble dietary fiber from bamboo shoot by-products) to pea protein isolate (PPI)-sodium alginate (SA) binary gels. The effects of pH and IDF content on the properties of PPI-SA binary gels were systematically investigated. Textural analysis, water retention measurements, and rheological studies showed that the IDF-SA-PPI hydrogels exhibited high gel strength, water retention capacity, and energy storage modulus. Fourier transform infrared (FTIR) spectroscopy indicated the appearance of new absorption peaks in the ternary composite gels, suggesting that hydrogen bonding and electrostatic interactions were the dominant molecular forces. Thermogravimetric analysis (TGA) demonstrated that the addition of IDF enhanced the thermal stability of the gels. Additionally, low-field nuclear magnetic resonance (LF-NMR) analysis revealed that IDF facilitated the conversion of free water to immobilized water within the gel matrix. The advanced ternary composite hydrogel was natural, sustainable, and robust, exhibiting significant potential as a multifunctional material across various applications. Additionally, it could enhance the utilization of bamboo shoot by-products in the food processing industry.
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