Gelatin-Based Nanobiocomposite Films as Sensitive Layers for Monitoring Relative Humidity in Food Packaging

Gelatin-based nanocomposite films were prepared by casting and characterized as a sensitive hybrid material to relative humidity changes in the development of electrical sensors. Zinc oxide nanoparticles (ZnO-NPs) and glycerol (Gly) were incorporated as reinforcing and plasticizing agents, respectively, and their effects on the sensibility property of films were investigated. The proposed sensors were investigated at 25 degrees C. The behavior of gelatin-based films as a function of water presence was analyzed in terms of moisture content (MC), water vapor permeability (WVP), and water contact angle (WCA). The incorporation of ZnO-NPs and Gly induced morphological and structural changes in the composite films. Increased WCA (7.51%) and reduced WVP (18%) were observed for the nanocomposite films. In addition, ZnO-NPs and Gly significantly contributed to a further improvement of relative humidity sensibility of films compared to the control film. Electrical characterizations, carried out at different environments for gelatin-based films, revealed a positive responsive relative humidity behavior of materials and a sensibility of 99.47% for hybrid materials, suggesting the development of a new promising nanocomposite material for monitoring relative humidity conditions at 25 degrees C.