Concentration effect of Quillaja saponin - Co-surfactant mixtures on emulsifying properties

Corina L Reichert; Hanna Salminen; Gabriela Badolato Bönisch; Christian Schäfer; Jochen Weiss

doi:10.1016/j.jcis.2018.01.105

Concentration effect of Quillaja saponin - Co-surfactant mixtures on emulsifying properties

J Colloid Interface Sci. 2018 Jun 1:519:71-80. doi: 10.1016/j.jcis.2018.01.105. Epub 2018 Feb 9.

Authors

Corina L Reichert¹, Hanna Salminen¹, Gabriela Badolato Bönisch², Christian Schäfer², Jochen Weiss³

Affiliations

¹ Department of Food Physics and Meat Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstraße 21/25, 70599 Stuttgart, Germany.
² DSM Nutritional Products Ltd., Research Center Formulation & Application, P.O. Box 2676, 4002 Basel, Switzerland.
³ Department of Food Physics and Meat Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstraße 21/25, 70599 Stuttgart, Germany. Electronic address: j.weiss@uni-hohenheim.de.

PMID: 29482098
DOI: 10.1016/j.jcis.2018.01.105

Abstract

Hypothesis: This study examined the emulsifying properties of mixed surfactant systems of Quillaja saponins 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.

Keywords: Binary surfactant system; Complex; Dynamic interfacial tension; Egg lecithin; Na-caseinate; Oil-in-water emulsion; Pea protein; Quillajasaponin; Rapeseed lecithin.