Résumé
This work aimed at characterizing the viscoelastic behavior and the fouling propensity of orange juice matrices composed of concentrated suspended particles (CSP) with defined size distributions. Small-, medium- and large-CSP (respectively colloids, supra-colloids and large particles) were first isolated and then mixed together according to a mixture design. The shear moduli, the specific resistance to filtration and the compressibility factor of isolated CSP and CSP mixtures were quantified. Small-, medium- and large-CSP were characterized by viscoelastic properties with a predominant solid-like behavior. The deposit layer of large-CSP had the highest shear moduli, while small-CSP presented the highest specific resistance to filtration. Small-, medium- and large-CSP deposit layers were considered as compressible matrices. The rheological behavior and the fouling propensity of mixtures of small-, medium- and large-CSP were analyzed using ternary diagrams. These diagrams revealed that the small-, medium- and large-CSP proportions modulated differently the shear moduli and the fouling propensity of CSP mixtures. Indeed, the solid-like behavior was strongly influenced by large-CSP proportions, the specific resistance to filtration depended mainly on the CSP size polydispersity, while small- or medium-CSP proportions had a major influence on the compressibility factor.