Effect of pH and Monovalent Ions on Composite Gels from Seaweed, Rice Protein, and Insoluble Fiber

The physicochemical properties of a composite gel composed of seaweed, rice protein, and date fibers are influenced by pH levels and the presence of monovalent cations. This investigation primarily aimed to examine the effects of pH variations (4, 6, and 8) and potassium ions (K+) on the functionality of seaweed-based composite gels. No syneresis was observed across any of the formulations. The hardness of the gel increased with the addition of KCl, suggesting that K+ ions reinforce the gel network. Similarly, moisture content was elevated in the presence of K+ ions, indicating an enhanced capacity of the gel network to retain water. Microstructural and rheological analyses support the formation of brittle gels when K⁺ ions are present at all tested pH levels (4, 6, and 8). Formulations lacking K⁺ ions produced less brittle and more deformable gels, consistent with microstructural images showing smaller and more uniform pores. The color of the gels was influenced by date fibers and varied with pH modifications. This research advances the understanding of composite gel formation and underscores the potential of date fruit fiber as an ingredient. Future investigations will aim to optimize the interactions between seaweed, rice protein, and date fibers under varying ionic conditions to further enhance the functional properties of these gels for diverse food applications.