Characterization of gelatin-based edible films incorporated with olive oil

Gelatin/olive oil composite films were prepared through microfluidic emulsification technique in order to reduce the water affinity of protein-based film. The effects of oil content on lipid droplet distributions in the film-forming dispersions and emulsified films were evaluated and compared. The possible relationship between some selected physical properties and microstructure (e.g., lipid droplet size) of the films was also discussed. The volume-surface (D3,2) and weight (D4,3) mean diameters of lipid droplets in film-forming dispersion showed a reduced trend upon increasing oil amounts, whereas the lipid droplets in the films showed a different trend, i.e., first increase and then decrease. The water barrier capability and tensile strength (TS) showed an enhanced trend as the lipid droplets in the films decreased. In addition, the emulsified films exhibited excellent barrier ability to ultraviolet light, and the inclusion of olive oil enhanced the hydrophobic character of gelatin films. These results revealed that olive oil has a good potential to be incorporated into gelatin to make edible film or coating for some food applications.

Research Highlights► Lipid droplet in FFD and films showed an opposite trend as the oil phase increased. ► Water barrier and tensile properties depended on the microstructure of the films. ► Olive oil incorporation improved water barrier and tensile property of gelatin films. ► Gelatin-olive oil emulsified films exhibited excellent barrier ability to UV light.