Variation of nanoparticles in pickering emulsion optimize the physical, control-release and sustained antioxidant properties of hydroxypropyl methylcellulose based microporous film.

The proper encapsulation of liposoluble tea polyphenols (LTP) is expected to better protect oil system. Chitosan hydrochloride-carboxymethyl starch (CHC-CMS) nanoparticles-based Pickering emulsions and hydroxypropyl methylcellulose/sodium citrate (HPMC/SC) microporous film were combined to embed and control-release LTP. With the CHC:CMS ratio varied from 1:0.5 to 1:2, the average size of LTP droplets of Pickering emulsion increased from 6.0 μm to 8.5 μm, the average area of cross-sectional pores of functional films increased from 1.78 μm to 3.22 μm, the water vapor permeability of functional films increased from 2.02 × 10 to 2.44 × 10 g·mm·s·Pa, the light transmittance and the quantity of cross-sectional pores decreased. The release ratio first increased (<24 days) and then remained stable (≥24 days), the stable release ratio was positively correlated with the size of the emulsion droplets in the emulsion and the size of cross-sectional pores in the film. Functional films had better protection effect on oil than free LTP during later storage period (≥32 days), among which, functional film containing CHC-CMS 1:2 showed optimal sustained antioxidant effect on Perilla seed oil, which corresponded well to its highest stable release ratio.