Gelatin-based films additivated with curcuma ethanol extract: Antioxidant activity and physical properties of films

Curcuma longa L. rhizomes contain curcuminoid pigments (more specifically, curcumin), which are phenolic compounds. These compounds can be incorporated into films for their functional properties (such as their antioxidant capacity), allowing this film to be used as food packaging. Thus, the aim of this study was to use curcuma ethanol extract to prepare gelatin-based films and evaluate the effects of the extract incorporation on the antioxidant and physical properties of the films. The gelatin-based films were produced by casting technique, and the curcuma ethanol extract (CEE) was incorporated at concentrations of 0, 5, 50, 100, 150, and 200 g/100 g of gelatin. The color parameters, light transmission, gloss measurements, microstructure, infrared spectroscopy characteristics, mechanical properties, moisture content, water-soluble matter, water vapor permeability and antioxidant capacity of the films were evaluated. Adding CEE to the gelatin-based films increased their ultraviolet and visible light barrier. Infrared spectroscopy analysis suggested there were interactions between the phenolic compounds of the extract and the gelatin, which may have improved the mechanical properties (tensile strength and elongation at break) and reduced both the water-soluble matter and water vapor permeability of the films. The antioxidant capacity of the films increased with increasing concentrations of CEE. The incorporation of curcuma ethanol extract conferred barrier properties and antioxidant capacity to the gelatin-based films.