Polarity-dependent interactions and structural organization in konjac glucomannan blends with pectin, carboxymethyl cellulose and ethyl cellulose

Polysaccharides are widely used in food and biomaterial systems, yet their structural complexity and hydration sensitivity complicate compatibility and stability assessment. This study investigated compatibility and structural organization of konjac glucomannan (KGM) blended with pectin (PEC), carboxymethyl cellulose (CMC) and ethyl cellulose (EC) using a multiscale characterization approach. Dispersions with varying KGM-to-polysaccharide ratios were analyzed by particle-size analysis, rheology, Turbiscan, FTIR, XRD and SEM, together with a lab-designed horizontal casting system coupled with near-infrared spectroscopy (CAST-SPECT) to assess spatial uniformity. The optimal formulations K9P1, K8C2 and K7E3 exhibited favorable size distributions, lower Span values and improved uniformity, indicating dispersibility and compatibility. Rheological measurements showed higher storage modulus and viscoelastic transition temperature with increasing KGM content, while three-interval thixotropy testing revealed composition-dependent structural rebuilding after high shear. Most KP and intermediate KC blends recovered close to their initial low-shear viscosity, whereas KE blends showed incomplete or recovery exceeding 100% depending on composition. Turbiscan confirmed kinetic stability of optimal formulations through lower TSI values and stable backscattering profiles. CAST-SPECT showed relative roundness errors below 0.20% after 120 h, consistent with near-infrared spectral correlation coefficients above 0.99. FTIR indicated composition-dependent hydrogen-bond rearrangement, while XRD revealed distinct crystalline reorganization among KP, KC and KE films. SEM showed smooth and compact morphologies in the optimized formulations, whereas excessive additive incorporation caused structural heterogeneity. Compatibility exhibited a polarity-related trend, with highly hydrophilic PEC requiring a lower incorporation level than CMC and EC. These findings provide insight into polarity-related interactions and structural organization in mixed polysaccharide systems.