Preparation and characterization of liposoluble tea polyphenol based functional emulsion films and the regulation of its releasing property

Functional films based on hydroxypropyl methylcellulose (HPMC)/ sodium citrate (SC) porous film and liposoluble tea polyphenol (LTP)/water Pickering emulsions stabilized by different contents of starch nanoparticles (NPs) were prepared. Addition of Pickering emulsion endowed the film surface pores, decreased oxygen permeability, water vapor permeability (WVP), hydrophilicity and good anti-oxidant effect. With increasing NPs, more smaller emulsion droplets appeared in the emulsion and filled into the porous structures of the film, the light transmittance and contact angle of the film increased. Functional film with 2 % NPs showed the lowest WVP and T_g, and highest stable LTP release ratio (4–12 week). That more surficial holes appeared and more emulsion droplets protrusions accumulated near the cross-sectional pores during the releasing process might facilitate the higher release of film-2 % NPs. The functional films have great potential to be used as light-shielding coatings, antioxidant capsule shells and sustained fresh-keeping “cards” for different oil systems.