Production and characterization of films based on gelatin, agave microfibers and nanoclays

The objective of this study was to produce and characterize gelatin films produced by thermo-compression, a technique that requires less processing time and space, making it appropriate for the development of commercial biodegradable protein-based films. A control film of gelatin with glycerol and water (M1) was compared with three films reinforced with Agave angustifolia Haw microfibers (MF) (M2-M4), three films reinforced with bentonite nanoclay (BN) (M5-M7), and three films reinforced with both MF and BN (M8-M10). The surface and cross-section morphology of the films showed some roughness with pores and inhomogeneities as the MF and BN concentration increased. The X-ray diffraction analysis confirmed the nanoclay intercalation. The films thickness was a function of the glycerol content, and all films had an apparent density slightly higher than unity. The films appearance was measured via the CIELab scale where the parameter a* was found to increase toward a reddish color, while b* showed an increasingly yellowish color. The presence of both MF and BN led to increased tortuosity inside the films, thus affecting the permeability of water molecules. Particles addition increased the tensile strength and elasticity, while the elongation at break decreased. The thermal stability improved with particles addition, especially for BN due to its inorganic nature. All the results could be related to a high level of interaction between the components and the protein matrix as observed via Fourier transform infrared spectroscopy, showing proper compatibility and a synergy among the materials. Due to the properties obtained, biomaterials can have good mechanical and high barrier properties combined with short life, disposable and environmentally friendly for food packaging and biomedical applications.