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

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 (C-G: 20, 26, 40, 56, or 60g gelatin/10 g water) and minimally processed carrot (C-F: 0, 1.5, 5, 8.5, or 10 g fiber/100 g 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 (C-G :C-F = 26:8.5 and 10:0 g/100 g 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 C-F, whereas the films containing only C-G in their matrix exhibited the highest tensile strength. The increasing C-F 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 C-G-C-F-based film had a less smooth surface when compared to the C-G-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 degrees 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. (C) 2015 Elsevier B.V. All rights reserved.