Preparation and characterization of pickering emulsions stabilized by zein/quercetin/quaternary ammonium chitosan composite nanoparticles with antibacterial effect

The role of nanoparticles in the stabilizing interface is very important in the preparation of stable Pickering emulsions. In this study, ternary composite nanoparticles (ZQ-HC) were synthesized by complexing zein-quercetin covalent complex (ZQ) with quaternary ammonium chitosan (HTCC) and subsequently stabilized Pickering emulsions (ZQ-HC) with antibacterial activity. Results revealed that HTCC covers the surface of ZQ nanoparticles successfully, which designates an effective improvement in the surface wettability of ZQ effectively. Among them, ZQ-HC_2:1 possesses the closest three-phase contact angle of 90° and the highest emulsification activity and emulsion stability. The results of ultra-high resolution microscopy showed that ZQ-HC nanoparticles were adsorbed at the oil-water interface to prevent droplet aggregation and improved the pH, ionic strength, and storage stability of the prepared Pickering emulsions. ZQ-HC nanoparticles construct an antioxidant barrier at the oil-water interface, improving the lipid oxidation stability of the emulsion. The ZQ-HC_2:1 stabilized Pickering emulsion exhibits the most superior stability and strongest antibacterial activity against other emulsions. The ZQ-HC stabilized Pickering emulsions prepared in this study exhibit potential for use as carriers of bioactive ingredients in food applications.