Concentration effect of Quillaja saponin – co-surfactant mixtures on emulsifying properties

Publikations-Art

Zeitschriftenbeitrag (peer-reviewed)

Autoren

Reichert, C.L, Salminen, H., Badolato Bönisch, G., Schaefer, C., Weiss, J.

Erscheinungsjahr

2018

Veröffentlicht in

Journal of Colloid and Surface Science

Band/Volume

519/

DOI

10.1016/j.jcis.2018.01.105

Seite (von - bis)

71-80

Hypothesis

This study examined the emulsifying properties of mixed surfactant systems of Quillajasaponins and food-grade co-surfactants (Na-caseinate, pea protein, rapeseed lecithin, and egg lecithin). We hypothesized to these mixtures may build mixed adsorption layers and thus enhance emulsion stabilization.

Experiments

Oil-in-water emulsions (10%, pH 7) were prepared with different concentrations of co-surfactants (0.1–5.0%) alone or mixed with Quillaja saponins (0.05 or 0.5%). Dynamic interfacial tension measurements were performed to characterize the behavior of the surfactants at an oil-water interface.

Findings

Low Quillaja saponin concentrations led to either no changes or substantial increases in particle sizes of protein stabilized emulsions, but d43-values decreased in lecithin stabilized emulsions at low lecithin concentrations. The dominating effect of Quillaja saponins at high concentrations led to formation of small droplets (d43 ≤ 2 µm) in all emulsions, except with 2.5% pea proteins. All co-surfactants showed synergistic or additive effects with respect to interfacial tension reductions upon addition of Quillaja saponins (except for egg lecithin with 0.005% Quillaja saponin addition). The results indicated a competing effect for saponin–protein interfaces, but formation of mixed saponin–lecithin interfaces, thus showing that the emulsion stabilization and interfacial properties can be tuned by specific binary surfactant mixtures.