Food-grade Pickering emulsions for encapsulation and delivery of bioactives

Background: Many biologically active and functional components are chemically unstable, and exhibit variable water/oil solubility, which reduce their bioavailability and efficacy. Therefore, the development and application of edible emulsion-based delivery systems for these compounds using food-grade materials would be extremely beneficial to the food industry. Recently, particle-stabilized emulsions (i.e., Pickering emulsions) have attracted significant attention from the scientific community owing to their surfactant-free character. Scope and approach: This Review summarizes the recent applications of Pickering emulsions stabilized by foodgrade particles for the encapsulation and delivery of lipophilic and hydrophilic bioactives. Firstly, the beneficial features of Pickering emulsions and their potential use for targeted delivery of bioactives are discussed. Next, different designs of Pickering emulsion-based delivery system (PEDS) and their performance in bioactives delivery are highlighted. Finally, the challenges and opportunities for future research are addressed. Key findings and conclusions: Particles derived from proteins, polysaccharides, and lipids have received considerable research interest owing to their intrinsic biochemical properties that enable the development of PEDS that can improve the stability and delivery of bioactives. Different types of PEDS (i.e., O/W or W/O single emulsions, O/W/O or W/O/W double emulsions, emulgel, high internal phase emulsion, and microcapsules) have been developed and studied as versatile tools for encapsulation of both lipophilic and hydrophilic bioactives. Future research should focus on the elucidation of the release mechanism of bioactives from PEDS and the evaluation of the compatibility of PEDS with real food systems, as well as the efficacy and safety of PEDS using in vivo model. Development of PEDS in non-liquid state should also be a focus for future research in order to bridge the gap between lab and market.