Optimization of functional nanoparticles formation in associative mixture of water-soluble portion of Farsi gum and beta-lactoglobulin.

Electrostatic interaction between beta-lactoglobulin (β-Lg) and water-soluble fraction of Farsi gum (WSFPG) was studied under the influence of pH, β-Lg:WSFPG mixing ratio (MR) and total concentration (TC) through performing various experiments such as turbidity, particle size and zeta potential measurements. Changes in the relative viscosity during in-situ acidification were studied at various ionic strengths. Lower amounts of absorbance and sedimentation were observed by decreasing the MR. An increase in the TC increased the absorbance of complexed samples. The smallest particle sizes, obtained at a same MR (1:3), were 108 and 188nm at TCs of 0.1 and 0.3wt%, respectively. The decreased relative viscosity upon acidification was a proof for the wrapping phenomenon in the biopolymer mixture. A further decrease in the relative viscosity was observed at higher ionic strength. The results of this study may facilitate the rational design of functional nanoparticles in associative mixtures of β-Lg and WSFPG.