Fabrication of High-Load Curcumin Emulsion Gels via Heat-Induced Confined Recrystallization and Polysaccharide–Beeswax Oleogel Synergy: Oxidation Protection and Gastrointestinal Delivery

Curcumin exhibits anti-inflammatory, antioxidant and lipid-regulating activities, yet it suffers from poor water and oil solubility, low loading capacity in conventional emulsions and facile recrystallization–sedimentation at high concentrations. This work presents a “polysaccharide–interfacial synergistic oleogel-mediated crystal interfacial adsorption” strategy. The oil phase composed of fish oil, coconut oil and beeswax undergoes heating–cooling treatment to induce confined recrystallization of curcumin and beeswax inside droplets, forming an oleogel matrix for crystal entrapment. The aqueous phase employs chitosan (CS) or electrostatically assembled chitosan–hyaluronic acid (CS-HA), with cinnamaldehyde–chitosan imine bonds constructed to build interfacial layers for stabilizing high-loading emulsions. Heating–cooling-treated emulsions achieve >95% curcumin encapsulation efficiencies, versus ~35% for non-heated controls. With increasing beeswax concentration, the onset melting temperature of crystals within emulsions decreased from 171.1 °C (CS-HA, without beeswax) to 98.8 °C (CS-HA + 6%, 6%, w/w, beeswax), enhancing emulsion gel strength and centrifugal and freeze–thaw stabilities. During in-vitro simulated digestion, the 2% (w/w) beeswax dual-polysaccharide emulsion (CS-HA + 2%) exhibits optimal digestive stability (79.49%), bioaccessibility (20.77%) and estimated colonic delivery rate (62.45%, ~32% higher than free oil). After 14-day accelerated storage at 45 °C, its primary oxidation products decrease by ~53% relative to free oil. This polysaccharide–oleogel emulsion system combines high curcumin loading, fish-oil antioxidation and colon delivery, providing references for high-dose oral delivery of hydrophobic bioactives.