Characteristics of Composite Gels Derived From Seaweed, Rice Protein, and Insoluble Dietary Fibers: Effect of pH and Monovalent Ions

ABSTRACT This study investigates the formulation and functionality of composite gels made from seaweed (SW), rice protein (RP), and date insoluble fiber (DIF), focusing on the effects of pH (4, 6, and 8) and monovalent cations (K + via KCl). Three formulations, SW, SW + RP, and SW + RP + DIF, were evaluated for physicochemical, textural, and structural properties. The incorporation of rice protein decreased gel hardness but increased adhesiveness and springiness, indicating enhanced elasticity and cohesive strength. The addition of date fiber further modified the texture by increasing hardness, likely due to matrix reinforcement by fiber particles. No syneresis was observed in any formulation. The addition of K + significantly increased gel hardness and moisture content, indicating the formation of stronger, more water‐retentive networks. Rheological and microstructural analyses confirmed that K + induced the formation of brittle gels with larger pores, whereas formulations without K + produced softer, less brittle gels with more compact and uniform structures. Color properties were also influenced by the addition of rice protein and date fiber, as well as pH, reflecting compositional, and pigment effects. From a sustainable protein perspective, this study demonstrates the potential of combining seaweed, rice protein, and fiber‐rich by‐products to create functional, plant‐based gel systems. The approach supports circular economy principles by utilizing renewable ingredients and food processing residues, offering viable alternatives to synthetic gelling agents and animal‐derived proteins.