Edible rice starch films incorporated with curcumin nanoparticles exerting anti-microbial properties for strawberry...

Pure starch film presents poor barrier properties and lacks anti-microbial properties. Herein, curcumin nanoparticles (cNPs) were prepared by the reassembly of food proteins and were utilized to reinforce the starch-based film. Herein, the reassembly of rice proteins and casein encapsulated curcumin upon pH adjustment to produce water-dispersible cNPs with a diameter of 140.9 ± 6.8 nm and curcumin loading capacity of 276.0 μg/mg. The cNPs showed a good dispersibility in gelatinized rice starch (RS) solutions as well and resultant composites films (RS@cNPs) had greater light barrier property than the pure RS film. The incorporation of cNPs tended to decrease the water solubility and water vapor permeability of RS@cNPs films, and increasing curcumin content gradually enhanced the hydrophobicity of RS@cNPs films. With a curcumin content of 3.0 %, the tensile strength of RS@cNPs was three times higher than the pure starch film. Besides, the RS@cNPs films coating prevented the growth of microorganism in the strawberries with a storage period of 3 days, and the pH value and soluble solids contents of strawberries in RS@cNPs group remained stable over storage period, suggesting that the RS@cNPs films coating preserved the freshness of strawberries and highlighted the preparation of novel starch-based films for food preservation.