Interrelationship between the zeta potential and viscoelastic properties in coacervates complexes

Abstract

The formation of the complex coacervate (CC) phases between gum Arabic (GA) and low molecular weight chitosan (Ch) and the interrelationship between the zeta-potential and viscoelastic properties of the coacervate phase were investigated. The maximum charge difference of biopolymers stock dispersion was displayed in a range of pH between 4.0 and 5.5. Titration experiment between the oppositely charged biopolymers showed that the isoelectric point was found at a biopolymers mass ratio (R[GA:Ch]) of R[5.5:1]. Turbidity, size and ζ-potential of the soluble complexes (SC) showed an interrelation with the complex coacervate yield (CCY). Higher CCY values (82.2-88.1%) were obtained in the range from R[3:1] to R[5.5:1]. Change the R[GA:Ch] in dispersion, make possible to produce CC's phases exhibiting cationic (R[1:1] and R[3:1]), neutral (R[5.5:1]) or anionic (R[9:1] and R[7:1]) charged. All CC's exhibited liquid-viscoelastic behavior at lower frequencies and a crossover between G″ and G' at higher frequencies.