From construction to application: a study on royal jelly-based Pickering emulsions for delivering Alpinia oxyphylla essential oil with 3D printing

Current research on 3D-printed foods for dysphagia has largely prioritized printability and structural fidelity, with limited attention to nutritional and biological functionality. We fabricated Pickering emulsions (PEs) loaded with Alpinia oxyphylla essential oil (AoEO) using royal jelly protein (RJP) as a natural stabilizer. Rheological analysis revealed gel-like behavior (tanδ < 1) and shear-thinning properties. At 40–50 mg/mL protein, storage modulus ( G ’) and apparent viscosity increased with protein concentration and oil volume fraction, promoting a stable three-dimensional network. The PE with 50 mg/mL protein and 70% oil phase showed superior extrudability and self-support, meeting IDDSI Level 5 (Minced & Moist) requirements. Bioactivity assays showed the MIC and MBC values of this PE were 10 and 30 mg/mL, while its IC 50 values for DPPH and ABTS radical scavenging were 4.236 and 62.751 mg/mL, respectively. Microstructural and FTIR analysis indicated that RJP formed a dense barrier at the oil-water interface, effectively encapsulating AoEO, reducing volatile loss, and enabling controlled release during intestinal digestion. These findings confirm that the emulsion possesses antibacterial and antioxidant effects, favorable 3D-printing properties, and sustained-release capacity, offering practical benefits for dysphagia patients.