Potato starch edible films to control oxidative rancidity of polyunsaturated lipids: effects of film composition, thickness and water activity

The objective of this work was to study the effect of potato starch-based films acting as oxygen barrier on the oxidative rancidity of vegetable oil, as an example of a food rich in polyunsaturated fatty acids. The effect of glycerol (Gly) content (0%, 10%, 20%, 30%), film thickness (30, 60, 100 μm) as well as environmental relative humidity (RH) (50% or 75%) were analysed. Results obtained confirmed that potato starch films delayed the rancidity in vegetable oil. Films without Gly provided the same protection as films with 10% Gly. Films with higher Gly content were not as effective oxygen barrier. It is likely that the fact that film protective capability diminished with increased RH or Gly content was due to the increasing moisture content of the films. Despite that fact, potato starch films can be considered a very efficient oxygen barrier even at RH as high as 75%.