Sorption kinetic of aroma compounds by edible bio-based films from marine-by product macromolecules: Effect of relative humidity conditions

Edible films based on gelatin and chitosan have high gas and aroma barrier properties. This study focused on their capability to sorbed/retain aroma compounds (1-hexanal, 2-hexen-1-ol, 1-hexanol, 3-hexanone and phenol) at three relative humidity level (< 2%, 53% or 84% RH). Whatever the relative humidity condition, the order of sorption is keton (3-hexanone) < aldehyde (1-hexanal) < aliphatic alcohols (2-hexen-1-ol and 1-hexanol) < phenol. This order could be related to the intrinsic chemical properties of aroma compounds. The increase in moisture enhanced the sorption at the highest RH for all the aroma compounds. However, a competition between water and aliphatic alcohols is observed at 53% RH. All compounds have an ideal sorption behaviour (logarithmic increase) except 1-hexanal. The sorption of 1-hexanal, 1-hexanol, 2-hexen-1-ol and 3-hexanone induced an antiplasticization of the network by increasing the film Tg by more than 5 degrees C. On the contrary, phenol was an efficient plasticizer at least as high as moisture.