Water-In-Oil Pickering Emulsions Stabilized by Microcrystalline Phytosterols in Oil: Fabrication Mechanism and Application as a Salt Release System

Abstract

Recently, Pickering emulsions stabilized by edible particles have attracted significant attention from the scientific community and food industry owing to their surfactant-free character. However, those edible particles are mostly used for stabilizing oil-in-water emulsions, whereas those for water-in-oil emulsions are very limited. In this article, stable water-in-oil Pickering emulsions were prepared through dispersing phytosterol particles in oil phase, and the effects of antisolvent treatment, the type of oil, particle concentration, and water fraction on the stability, type, and morphology of these emulsions were investigated. In addition, the release profile of salt as a model aqueous compound from these emulsions has also been studied. Results showed that due to its higher water content, the antisolvent pretreatment of phytosterol in the ethanol/water system facilitated the dispersion of dried phytosterol particles into oil phase as microcrystals. Water-in-oil Pickering emulsions with droplet sizes of 80–100 μm were fabricated at phytosterol concentrations of 1.5–3% w/v and water fractions of 0.2–0.6. The dissolved phytosterol molecules in oil phase could help in emulsion stabilization through interfacial crystallization during emulsification, evidenced by polar microscopic observations. Moreover, the salt release from phytosterol-stabilized Pickering emulsions showed a temperature-dependent profile which could have potential application in a controlled-release system. The current study provided important information for fabrication of stable water-in-oil emulsion using natural particles.

Correlation Relationship between Phase Inversion of Pickering Emulsions and Biocatalytic Activity of Microbial Transformation of Phytosterols

“…In our previous work, we confirmed that hydrophobic M. neoaurum cells act as solid particles to stabilize W/O Pickering emulsions [15]. It has also been reported that phytosterol crystals act as solid particles to stabilize W/O Pickering emulsions [24]. Furthermore, adsorption of M. neoaurum cells onto phytosterol crystals to form crystal phytosterol-bacteria microaggregates, which has been confirmed by CLSM analysis, exhibits wettability unlike that of crystal phytosterol particles or bacteria [16].…”

“…1), and it had already been confirmed that the Pickering emulsions were stabilized by phytosterol crystals as solid emulsifiers [16]. Very recently, phytosterol crystals have also been utilized as emulsifiers for the fabrication of eatable W/O Pickering emulsions in the food field [24]. With the progress of microbial transfor-…”

Progress in the Application of Food-Grade Emulsions

“…Due to the significant health risks associated with a high-salt intake, the development of salt-reducing foods has received growing attention [ 196 ]. In this context, Wang et al [ 197 ] discussed a promising method for regulating the salinity by reducing the sodium content through the emulsion-based delivery of NaCl.…”

Soy Protein Isolate/Genipin-Based Nanoparticles for the Stabilization of Pickering Emulsion to Design Self-Healing Guar Gum-Based Hydrogels

“…Biopolymer-based food-grade nanoparticles (e.g., protein, 24 polysaccharide, 25 and lipid) which play the role of Pickering emulsion stabilizers have attracted formulation scientists and gained increasing popularity in the past couple of years. 26 Soybean, a kind of abundant natural resource, possesses excellent nutritional value and low production costs. 27 Besides, soy protein isolate (SPI), possessing 18 diverse amino acids, is an enriched commercial form of soy protein.…”