Active films produced with gelatin from the skin of hake fish (Cynoscion acoupa) and essential
oil (EO) Piper divaricatum were obtained by two techniques: impregnation by supercritical
CO2 (scCO2) and casting. Initially, the process of impregnating the EO in the gelatin film was
carried out using CO2 as a supercritical solvent, in an autoclave at 35 º C, at pressures of 100,
150 and 200 bar and times of 60, 90 and 120 min. The active film that showed the highest
percentage of inhibition of antioxidant activity (IAA%) was obtained at 100 bar and 60 min
(41.63±1.6%). Scanning electron microscopy (SEM) showed that the EO presented
heterogeneous distribution in the film, confirming the impregnation. The scCO2 impregnation
resulted in a film with lower tensile strength and thermal stability, greater flexibility and opacity
when compared to the control, indicating the potential of this technique to obtain active
packaging for food products. After determining the best parameter of the impregnation process,
the concentrations of 10%, 20% and 30% of the EO in the gelatin film were compared by the
casting and impregnation techniques by scCO2. The films obtained with the addition of 20%
(71.97±1.71) and 30% (79.17±1.01) of EO produced by casting showed the highest retentions
of the IAA%. Films made by scCO2 impregnation showed lower antioxidant activity, but this
was improved with increasing EO content from 20% (23.57±1.45) to 30% (33.66±2.42).
Through scanning electron microscopy (SEM) images, oil droplets with heterogeneous
distribution were observed in films impregnated by scCO2 and homogeneous surface by the
casting technique. The films impregnated with scCO2 proved to be transparent, resistant to
traction, elastic and with greater thermal stability. Meanwhile, the films produced by casting
showed greater resistance to moisture and greater protection from UV light. The casting
technique showed greater potential for the production of active packaging, as the film showed
better antioxidant potential with the incorporation of EO and the use of emulsifier in the film
solution. Impregnation by scCO2 showed potential to obtain the active film, however further
studies should be carried out to improve the limitations of oil retention in the film found in this
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