Characterization of sodium caseinate-based edible films incorporated with cinnamon or ginger essential oils

Film-forming emulsions were formulated with sodium caseinate and two essential oils (cinnamon or ginger) and films were obtained by casting. At the low oil proportion being tested (maximum ratio protein:oil 1:0.100), the lipid did not affect the mechanical behaviour of the protein films. The water vapour permeability was slightly reduced by both oils. Cinnamon oil greatly affected the optical properties of the films. Ginger oil resulted in lipid droplet aggregation observable by Scanning Electron Microscopy in dried films, surface irregularities and gloss decrease. Neither of the oils improved the ability of sodium caseinate films to act as protection against lipid oxidation, despite the fact that, in a spectrophotometric method, isolated cinnamon oil proved to be very a strong antioxidant.