All-natural plant-based HIPE-gels simultaneously stabilizing with Quillaja saponin and soy protein isolate: Influence of environmental stresses on stability

All-natural plant protein-based high internal phase emulsion gels (HIPE-Gels) have attracted increasing attention recently in food, cosmetic, pharmaceutical, and other fields. Herein, HIPE-Gels were simultaneously fabricated by natural Quillaja saponin (QS) and soy protein isolate (SPI), and investigated the effects of environmental factors i.e., storage, acidic, ionic strength, heating and freeze-thawing on their physical stability. The combination of SPI and QS enabled the highly stable O/W emulsion gels with a shear-thinning behavior. At the appropriate concentration (i.e., 1.5% SPI and 0.09% QS), the emulsion gels exhibited high tolerance toward long-term storage and destabilizing environments. Although poor stability at a pH close to the isoelectric point of SPI, incorporating QS provided excellent acidic stability of plant-based emulsion gels. The strong electrostatic repulsion provided by QS would reduce the aggregation between droplets under acid environment and the electrostatic shielding of salt ions, improving the acid tolerance and salt tolerance of SPI-based emulsion gels. In addition, QS had also improved their thermal stability and freeze-thaw stability. These findings demonstrated that the combination of SPI and QS could provide an effective strategy to fabricate all-natural plant protein-based mayonnaise to withstand several environmental factors, developing label-friendly novel food products.