Dual-modified starch as particulate emulsifier for Pickering emulsion: Structure, safety properties, and application for encapsulating curcumin

In this study, cinnamic acid modified acid-ethanol hydrolyzed starch (CAES) with different degrees of substitution (DS) was fabricated to stabilize Pickering emulsions and probed their application for encapsulating curcumin (Cur). Successful preparation of CAES (with DS from 0.016 to 0.191) was confirmed by 1H NMR and FT-IR, and their physicochemical properties were characterized by XRD, SEM, and TGA. The biosafety evaluations and surface wettability confirmed the excellent safety and amphiphilic character of CAES. CAES-stabilized Pickering emulsion (CS-PE) exhibited different emulsion stability at different DS, with CS-PE (0.031) showing the highest stability. CLSM revealed that the CAES (0.031) formed a dense barrier on the surface of the oil droplets, preventing them from coalescing. The CS-PE (0.031) achieved effective encapsulation of Cur (up to 96.2 %). Compared with free Cur, CS-PE (0.031) exhibited better photochemical stability, higher free fatty acids (FFA) release, and enhanced bioaccessibility. These studies suggested that CAES may serve as a promising emulsifier for stabilizing Pickering emulsions to encapsulate and deliver hydrophobic bioactive compounds.