Effect of pH and protein particle shape on the stability of amylopectin-xyloglucan water-in-water emulsions

We studied the incompatibility between the polysaccharides amylopectin (AMP) and xyloglucan (XG) from tamarind seed and also generated a phase diagram of mixtures of these polymers. We evaluated the effect of XG concentration on the stability of water-in-water emulsions. Using protein particles with varying shapes produced from beta-lactoglobulin (microgels and nanofibrils), we measured the stability of AMP and XG emulsions and the particle adsorption at the interface at various pH values. At pH < 5, microgels stabilized the emulsions, while at higher pH values, the interaction between the AMP-rich phase and particles led to the formation of a strong gel phase. Compared to spherical particles used in water-in-water emulsion stabilization, the adsorption of nanofibrils at the interface of AMP with XG occurred at pH 4 and 5 as well as at pH 6 and 7. At the latter pH, AMP droplets were observed in the XG continuous phase for up to 24 h.