Nanoemulsions have attracted significant attention in food fields and can increase the functionality of the bioactive compounds contained within them. In this paper, the preparation methods, including low-energy and high-energy methods, were first reviewed. Second, the physical and chemical destabilization mechanisms of nanoemulsions, such as gravitational separation (creaming or sedimentation), flocculation, coalescence, Ostwald ripening, lipid oxidation and so on, were reviewed. Then, the impact of different stabilizers, including emulsifiers, weighting agents, texture modifiers (thickening agents and gelling agents), ripening inhibitors, antioxidants and chelating agents, on the physicochemical stability of nanoemulsions were discussed. Finally, the applications of nanoemulsions for the delivery of functional ingredients, including bioactive lipids, essential oil, flavor compounds, vitamins, phenolic compounds and carotenoids, were summarized. This review can provide some reference for the selection of preparation methods and stabilizers that will improve performance in nanoemulsion-based products and expand their usage.

The influence of ultrasonic treatment (100-500 W, 30 min) on the molecular structures and emulsifying properties of Zanthoxylum seed protein (ZSP) was explored for the first time in this work. Research results indicated that the all ultrasonic treatments at different power levels decreased the particle size but increased the surface charge of ZSP. In addition, the ultrasonic treatments induced the structural unfolding of the ZAP, as indicated by the increase in α-helix, ultraviolet-visible absorbance, surface hydrophobicity and the amount of surface free sulfhydryl groups, as well as the decrease in β-sheet and intrinsic fluorescence intensity. As a result, the significantly (p < 0.05) increased emulsifying activity index (EAI) and emulsion stability index (ESI) of ZSP were observed after ultrasonic treatment. In addition, the emulsion prepared by ultrasonically treated ZSP exhibited the smaller and more uniform droplets with significantly improved stability against environmental stress (temperature, salt concentration, pH), creaming and oxidation due to the increased ratio of interfacially adsorbed ZSP. Furthermore, ultrasonic treatment at 400 W was found to be the optimum condition for modification. These findings will provide a theoretical foundation for the utilization of ultrasound in enhancing the emulsifying properties of ZSP and promoting its application in the field of food processing.

The aim of this study was to microencapsulate probiotic bacteria (Lactobacillus acidophilus 11073) using whey-protein-isolate (WPI)–octenyl-succinic-anhydride-starch (OSA-starch)-complex coacervates and to investigate the effects on probiotic bacterial viability during spray drying, simulated gastrointestinal digestion, thermal treatment and long-term storage. The optimum mixing ratio and pH for the preparation of WPI-OSA-starch-complex coacervates were determined to be 2:1 and 4.0, respectively. The combination of WPI and OSA starch under these conditions produced microcapsules with smoother surfaces and more compact structures than WPI-OSA starch alone, due to the electrostatic attraction between WPI and OSA starch. As a result, WPI-OSA-starch microcapsules showed significantly (p < 0.05) higher viability (95.94 ± 1.64%) after spray drying and significantly (p < 0.05) better protection during simulated gastrointestinal digestion, heating (65 °C/30 min and 75 °C/10 min) and storage (4/25 °C for 12 weeks) than WPI-OSA-starch microcapsules. These results demonstrated that WPI-OSA-starch-complex coacervates have excellent potential as a novel wall material for probiotic microencapsulation.