Investigations into the structure-function relationship of plant-based surfactant glycyrrhizin: Interfacial behavior & emulsion formation

This study describes the interfacial and emulsifying properties of a plant-based saponin glycyrrhizin and its aglycone 18β-glycyrrhetinic acid derived from licorice root (Glycyrrhiza glabra L.) to enable first insights into a potential structure-function relationship. First, the surface activity of glycyrrhizin and its aglycone at air-water and oil-water interfaces, and the viscoelastic behavior at an oil-water interface was examined. Second, the emulsifying properties by preparing oil-in-water emulsions (100 g oil/kg emulsion, pH 7) by high-pressure homogenization was evaluated. Both glycyrrhizin and its aglycone reduced surface and interfacial activity only