Effect of Addition of Halloysite Nanoclay and SiO2 Nanoparticles on Barrier and Mechanical Properties of Bovine Gelatin Films

Casting method was used to prepare bovine gelatin based bio-nanocomposite films with halloysite nanoclay and nano-SiO2 as the reinforcing materials. The composition included gelatin with 20% (w/w) of glycerol (as plasticizer) compounded with halloysite nanoclay and nano-SiO2 (0%, 2%, 3%, 4%, 5% w/w), respectively. Both types of nanocomposite films showed better mechanical and water solubility than the pristine gelatin films. On comparison with the control, increase in the nanoparticles content resulted in higher tensile strength (9.19 to 13.39 and 12.22 MPa in nanoclay and nano-SiO2, respectively) and elastic modulus (1.32 to 2.99 and 3.02 MPa% in nanoclay and nano-SiO2, respectively) with lower elongation at break (80.80 to 55.72 and 40.31% in nanoclay and nano-SiO2, respectively) and water solubility (85.99 to 69.67 and 69.59% in nanoclay and nano-SiO2, respectively). Even though a decrease in water vapor permeability was recorded, it was statistically non-significant (1.94 to 1.50 and 1.73 g mm/m(2) h kPa in nanoclay and nano-SiO2, respectively). Studies on the heat sealing and peel seal test, conducted to determine the seal strength of the nanocomposite films, revealed lower seal strength compared to control (739.59 to 304.95 and 397.85 N/m in nanoclay and nano-SiO2, respectively). Between the two nanomaterials used, halloysite nanoclay showed the best results in terms of mechanical properties. The results obtained support the concept of nanocomposite technology and can be employed to improve the barrier and mechanical properties of bovine gelatin films with high potential to be used for food packaging purposes.