Fabrication and Characterization of Ampelopsis grossedentata Leaf Powder-Stabilized Pickering Emulsion Gels

Abstract

Natural carrier systems that integrate structural integrity with protective function are critical for the efficient delivery of lipophilic bioactives. Here, we employed Ampelopsis grossedentata leaf powder (AGP), a flavonoid-rich plant material, as a particulate stabilizer to construct Pickering emulsion gels. The influence of AGP concentration and oil phase volume fraction on gel structure was examined, and the ability of the gels to protect lutein was further assessed. AGP displayed appropriate interfacial wettability, enabling it to adsorb at the oil–water interface and build a coherent particle layer. A progressive increase in AGP concentration reduced droplet size and raised gel strength from 3.07 × 10−2 N to 5.04 × 10−2 N, reflecting the formation of a more robust particle-based network. Among the formulations tested, the gel prepared with 4% AGP gave the best overall structural performance: it had the highest gel strength, together with favorable elasticity index (EI) and macroscopic viscosity index (MVI) values, indicative of superior load-bearing capacity and disturbance resistance. Raising the oil phase fraction further tightened droplet packing and improved structural stability. In storage trials, the optimized AGP-stabilized emulsion gel retained substantially more lutein than the MCT oil system without powder, with the 7-day retention increasing from 14.9% to 55.9%. This protective effect may be attributed to the physical barrier created by interfacial particles, together with the antioxidant activity of flavonoids naturally present in AGP. These findings uncover a synergistic role of plant-based particles in structuring Pickering emulsion gels and preserving lipophilic bioactives, highlighting AGP as a sustainable and functional platform for delivery systems.