Such interface-dominated food systems as plant protein-based emulsions and foams have some problems such as difficulty in preparation, environmental susceptibility and instability, which can be solved using a multi-dimensional strategy of “molecule-interface-droplets/bubbles” based on the interactions between saponins and plant proteins. This review summarizes the interactions in the water phase and at the interface of plant proteins and saponins and their adsorption and stabilization behaviors, and reveals the construction and stabilization of emulsion- and foam-based food systems and the relationship between them at the molecular level and from a macroscopic point of view in order to provide theoretical support for the preparation, stabilization and functional properties of plant-based interface-dominated foods.

In this study, the synergistic effect of Quillaja saponin (QS) and soybean protein isolate (SPI) on stabilizing emulsion gels was used to prepare plant-based mayonnaise (PM) with high protein content and reduced fat content. Comparative characterization of PM and two commercially mayonnaises in terms of appearance, droplet size, texture, rheological properties, thermal and freeze-thaw stability was conducted by static light scattering, laser confocal scanning microscopy (LCSM), small deformation rheology and texture profile analysis (TPA). It was found that high-protein and fat-reduced MP (10% SPI and 50% fat or 11% SPI and 40% fat, m/m) which was compared to commercial mayonnaises in terms of appearance, spreadability, texture and rheological properties was made using 10% SPI and 0.18% QS or 10% SPI, 0.18%QS and 1% SPI gel particles (SGPs) as protein ingredients. In the systems, QS not only endowed a viscosity-thinning texture modifier to protein-rich emulsion products, but also imparted superior thermal stability and freeze-thaw stability to SPI-based emulsion gels. These findings will provide theoretical and technical guidance for the development and application of high-protein and fat-reduced plant-based mayonnaise.