Residues of minimally processed carrot and gelatin capsules: Potential materials for packaging films

Abstract

The development of biocomposite materials from renewable resources is an attractive alternative to substitute synthetic and non-biodegradable plastics. This study aimed to develop biodegradable films from industrial residues and investigate the effects of different concentrations of residues of gelatin capsules (CG: 20, 26, 40, 56, or 60g gelatin/100g water) and minimally processed carrot (CF: 0, 1.5, 5, 8.5, or 10g fiber/100g water) with a high content of total dietary fiber on the antioxidant, physicochemical, barrier, mechanical and optical properties of biodegradable films using a response-surface methodology. Two film formulations considered to present adequate and optimized properties (CG:CF=26:8.5 and 10:0g/100g water) were selected to have their microstructure, thermal properties and protection against oil primary oxidation process evaluated in order to verify their functionality. The results demonstrated that the DPPH radical scavenging activity, moisture content, water solubility and water vapor permeability were improved with the increasing addition of CF, whereas the films containing only CG in their matrix exhibited the highest tensile strength. The increasing CF has also contributed to the greater values of opacity and Young's Modulus, and lower light transmission and elongation at break. SEM photomicrographs indicated that the CG–CF-based film had a less smooth surface when compared to the CG-based film, which was attributed to the presence of insoluble fiber particles in the biocomposite. Thermogravimetric analysis suggested that both of the films were thermally stable until near 200°C. Additionally, the films retarded the primary oxidation of packed sunflower oil under accelerated oxidation conditions. Based on the results, this research demonstrated that the use of residues to form biodegradable films represents a promising alternative for the production of sustainable and active packaging and for the development of eco-friendly technologies.