Impact of concentration and dispersion rate on particle size distribution, viscoelasticity and physical stability of aqueous citric fibre dispersions

Abstract

This study evaluates the effect of citrus fiber concentration (3.5–6.5 % wt%) and homogenization rate (2000 and 8000 rpm) on the particle size distribution (PSD), viscoelastic properties, and physical stability of aqueous dispersions. The PSD showed a monomodal profile with diameters centered around 100 μm. At 2000 rpm, fiber concentration did not significantly influence the PSD or mean diameters, while at 8000 rpm, a progressive broadening of the distribution with concentration was observed. The viscoelastic behavior showed an increase in the complex shear modulus (G*) and critical stress with increasing concentration and homogenization rate, indicating a stronger three-dimensional network. However, a saturation point was observed in the structural strengthening at high concentrations. Physical stability, assessed by multiple light scattering, revealed that at low concentrations, a higher homogenization rate improves stability, while high concentrations can intensify instability. Overall, the results underscore the importance of balancing fiber concentration and processing conditions to optimize structural and stability properties in citrus fiber-based systems.