Functional cookies with improved flavor, digestibility and shelf life via application of Camellia seed oil-based emulsion gel for grape seed polyphenol delivery

To address the instability of grape seed polyphenols (GSP) and the lipid composition of traditional butter cookies, this study employed a camellia seed oil-based emulsion gel loaded with GSP as a butter substitute. Optimal conditions were established at an oil-to-water ratio of 7:3 and a gelatin concentration of 3%, yielding an oil-holding capacity of 89.5% and a uniform microstructure. Incorporating 0.1% GSP enhanced the gel network through hydrogen bonding, conferring more robust shear-thinning properties and excellent thermal processing tolerance. When applied to cookies, this gel produced optimal sensory ratings. This formulation reduced rapidly digestible starch by approximately 4.7% and increased resistant starch by about 7.9%, significantly delaying starch digestion rates. Its antioxidant properties extended shelf life to 1.6–1.9 times that of the control group. This system offers a novel strategy for developing functional baked goods with enhanced flavor, digestive properties, and shelf life.