Trends in Food Science & Technology 107 (2021) 1–15 Available online 30 November 2020 0924-2244/© 2020 Elsevier Ltd. All rights reserved. Physicochemical characteristics, applications and research trends of edible Pickering emulsions Tianhang Xia a , Changhu Xue a, b, ** , Zihao Wei a, * a College of Food Science and Engineering, Ocean University of China, Qingdao, 266003, China b Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, China A R T I C L E INFO Keywords: Edible pickering emulsion Complex particle Desirable stability Smart delivery system Tunable digestion Application trend ABSTRACT Background: In recent years, Pickering emulsions have attracted wide attentions due to their enhanced stability and numerous possible applications compared to conventional emulsions. In the feld of food science, the application of food-grade particles endows the Pickering emulsions with a broader prospect. Scope and approach: This paper elaborates the factors affecting the stability of Pickering emulsions and sum- marizes various physicochemical properties of Pickering emulsions. Besides, the available food-grade particles that have been recently developed as Pickering stabilizers are summarized. Furthermore, the applications of edible Pickering emulsions and their future trends are highlighted. Key fndings and conclusions: The stability of Pickering emulsions is affected by three factors: particle as Pickering stabilizer, water phase and oil phase. Food-grade particles for Pickering emulsion applications are mainly divided into six categories: polysaccharide particles, protein-based particles, complex particles, favonoid particles, food- grade wax and fat crystals, which can be modifed by physical or chemical methods to enhance their Pickering emulsifer performance. Fat substitute, nutraceutical delivery and cleaning agent in replacement of detergents are potential applications of food-grade Pickering emulsions. The research trends of food-grade particle-stabi- lized Pickering emulsions include Pickering double emulsions, nutraceutical co-delivery, multilayer Pickering emulsions, fxing the Pickering emulsions in the gel, preparation of porous materials and responsive Pickering emulsions. It can be concluded that the food industry will have a great revolution with the development of Pickering emulsions. 1. Introduction Emulsion is a dispersed system consisting of several immiscible liq- uids which have wide applications in the food industry. For example, milk, butter and ice cream cannot be manufactured without emulsion systems. The conventional emulsions stabilized by surfactants or amphiphilic macromolecules with good solubility (e.g., protein and polysaccharide) are usually thermodynamically unstable and tend to break down owing to coalescence, focculation and Ostwald ripening over time (McClements, 2012). On the contrary, Pickering emulsions show better stability such as anti-coalescence and anti-Ostwald ripening stability (Matos et al., 2018). The main reason for the difference is their distinct mechanism of stabilization. The stabilization of conventional emulsions is mainly realized by a combination of electrostatic stabili- zation, reducing interfacial tension and steric stabilization with the aid of surfactants or soluble macromolecules. The adsorption of conven- tional emulsifers (e.g., surfactants, etc.) at the oil-water interface in conventional emulsions is usually reversible. For Pickering emulsions, the particles adsorbed at the oil-water interface form a physical barrier, which can block the interface interaction and droplet contact through volume exclusion, and particles adsorb at the interface are considered as irreversible. Distinct stabilization mechanisms endow the emulsions with different interfacial properties. Due to the adsorption of particles, Pickering emulsions have higher surface load and thickness than con- ventional emulsions. On the other hand, conventional emulsifers will have dynamic exchange at the interface, which is not observed in Pickering emulsions (Jafari, Sedaghat Doost, Nikbakht Nasrabadi, Boostani, & Van der Meeren, 2020). Pickering emulsions are stabilized by insoluble solid particles. The wettability and size of the particles are the main factors affecting the * Corresponding author. ** Corresponding author. College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao, Shandong Province, 266003, China, E-mail addresses: xuech@ouc.edu.cn (C. Xue), weizihao@ouc.edu.cn (Z. Wei). Contents lists available at ScienceDirect Trends in Food Science & Technology journal homepage: www.elsevier.com/locate/tifs https://doi.org/10.1016/j.tifs.2020.11.019 Received 15 August 2020; Received in revised form 13 November 2020; Accepted 21 November 2020