Effect of pH and protein to polysaccharide ratio on coacervation of sesame protein isolate-Tragacanth gum: Structure-rheology function.

The electrostatic complexes of sesame protein isolate (SPI) and Tragacanth gum (TRG) as a function of pH (2-8) and biopolymer ratios on their interactions and characterization was investigated. The optimal pH of coacervation was found ~5.0 and ratio of 5:1, which facilitated the strongest electrostatic interactions and highest turbidity for complex formation. Rheological assessments revealed that SPI/TRG coacervates exhibited robust gel-like behavior, characterized by a dominating elastic modulus, indicative of a strong interconnected network structure which was achieved at a ratio of 5:1 SPI to TRG at pH 5.0, suggesting suitability for its bioactive encapsulation. Fourier transform infrared spectroscopy confirmed the presence of both electrostatic interactions and hydrogen bonding during coacervation. Thermal analysis indicated that SPI/TRG coacervates possess enhanced thermal stability compared to the individual components. SEM images and dynamic light scattering provided insights into the morphological characteristics, revealing the impact of hydration and encapsulation on particle size and surface structure. This research contributes to the development of sustainable plant-based ingredients with functional applications in the food industry, paving the way for future studies aimed at optimizing SPI/TRG formulations for specific applications within food systems. The findings underscore the potential of SPI/TRG coacervates as innovative, health-oriented food ingredients.