Preparation and characterization of emulsions of soy protein isolate-chitosan quaternary ammonium salt complexes and peppermint essential oil with extended release effect

Abstract

In this study, we report for and first use of soy protein isolate (SPI), chitosan quaternary ammonium salt (HACC), and peppermint essential oil (PMO) to prepare emulsions. Under different SPI/HACC ratios, emulsions with an oil-phase ratio of 60% were produced using the high-speed shearing machine (i.e., 1:0, 1:1, 2:1, and 5:1). The outcome of rheological experiment demonstrated that the addition of HACC boosted the viscosity and improved gel network structure of emulsions. The stability and microstructure of the emulsion also improved as the content of HACC was increased. Also, the evaporation rate of essential oil from the emulsions was examined. The release duration of PMO was also significantly extended by the emulsions, and its capacity to inhibit the growth of three plant pathogenic fungi was enhanced. Therefore, this study suggested that HACC can greatly improved the emulsification stability of SPI as well as essential oil emulsion stabilized by SPI/HACC composite with a ratio of 1:1 had the best slow release effect. The PMO emulsions that were created had great promise for embedding volatile, water-insoluble, and micromolecular chemicals.