Grape seed polyphenol water‐in‐oil emulsion: preparation and application in functional cookies

Abstract Background The study aimed to address the characteristics of grape seed polyphenols (GSPs), such as high hydrophilicity and poor stability in fats and oils, as well as the poor digestive properties of traditional cookies due to their high fat content. A GSP delivery system based on water‐in‐oil (W/O) emulsion technology was innovatively developed, aiming at solving the difficult problem of the limited application of GSPs in high‐fat cookie systems. In this study, we explored the potential application of GSPs in functional cookie products by constructing a GSP–tea seed oil stabilized emulsion system. Results Emulsion systems prepared by high‐speed shear emulsification demonstrate superior performance (water–oil ratio of 2:8, polyglyceryl ricinoleate concentration of 50 g kg −1 , sucrose concentration of 30 g kg −1 , with 0.1% GSP added). The emulsion had an emulsification index of <1%, a zeta potential of 44.2 ± 0.5 mV and remained stable for many days after storage at 4 °C. Confocal laser scanning microscopy confirmed that the emulsion possessed a typical W/O structure, and GSP improved the thermal stability of the emulsion by 0.8 °C through the formation of a three‐dimensional hydrogen bonding network, achieving a DPPH radical scavenging rate of 99.63%. After application in biscuit products, the shelf‐life was extended by 37.32%, and the rapidly digestible starch (RDS) decreased to 41.17%. Conclusion We successfully constructed a GSP‐enhanced functional emulsion system and elucidated its mechanism of action in improving product quality through a dual mechanism of amylase inhibition and antioxidant activity. This technology provides a new solution for developing healthy bakery products, although its industrial application still requires further work to address stability issues under extreme conditions. The findings of this study offer important guidance for applying plant polyphenols in food colloidal systems. © 2025 Society of Chemical Industry.