How composition and process parameters affect volatile active compounds in biopolymer films

Active edible films based on chitosan and containing an active aroma compound have been investigated. The influence of the composition of the film forming solution (solvent, plasticizers, nanoparticles, emulsifiers and aroma traps) and process parameters (temperature and viscosity) on drying kinetics, water content, colour, aroma compound retention and partition coefficient was studied. Solvent evaporation rate was increased by addition of ethanol. Water evaporation was delayed by glycerol. The aroma retention during film drying was directly related to the water content. The drying temperature had opposite influences according to the composition of the solvent and additives. Increasing temperature from 20 to 100 °C could increase 3 times the retention of aroma compounds. The viscosity of film forming solutions was strongly increased by biopolymer content and glycerol but reduced by carvacrol and ethanol. To improve carvacrol retention, the most efficient additive was gum arabic, followed by glycerol whereas the effect of nanoclays or emulsifiers remained weak.