Supercritical CO2 impregnation of Gelatin-Chitosan films with clove essential oil and characterization thereof

Abstract

Supercritical CO2 impregnation process was used for the first time to fabricate biodegradable gelatin-chitosan (G/Ch) films containing clove oil (CO) for potential use in active food packaging. All the impregnations were carried out at moderately low temperature (40°C). Aiming to maximize CO loading in the films with acceptable morphological, structural and thermal properties, CO2 pressure, impregnation time and G:Ch mass ratio were varied. Gelatin fraction in the films of 25-50 wt.%, scCO2 pressures of 10-20 MPa and impregnation time of 2-6 h impregnation favoured the CO loading. Processing of the film with equal gelatin to chitosan mass ratio (G/Ch50:50) at 10 MPa for 2 h yielded sufficiently high loading (56 mg CO/gfilm) without an adverse effect on morphological properties. The G/Ch50:50 film was therefore chosen for structural and thermal analyses. ATR-FTIR analysis confirmed successful CO incorporation into the G/Ch50:50 and its interaction with the film. Plasticizing effect of scCO2 and CO on the film was evidenced by DSC. Incorporation of 56 mg CO/gfilm into the G/Ch50:50 didn''t affect thermal stability of the film. Beside environmental benefits, supercritical impregnation process enables fast fabrication of G/Ch bio-composite films containing CO, thermally stable to 110°C, which is suitable for most of food packaging applications. [Projects of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 45017 and Grant no. III45007]

Keywords

• chitosan
• clove oil
• composite film
• gelatin
• impregnation
• supercritical CO2