Nano-Rheological Behaviour of Cassava Starch-Zinc Nanocomposite Film under Dynamic Loading for High Speed Transportation of Packaged Food

Abstract

This research was undertaken to determine the nano–rheological behaviours of cassava starch–zinc–nanocomposite fims under dynamic loading for assessing their suitability as food packaging materials in high speed transportation. The fimsǰ with thickness ranging between 15 ± 0.22–17 ± 0.13 µm, were prepared by casting mixtures of 24 g cassava starch, 45–55% (w/w) glycerol and 0–2% (w/w) zinc nanoparticles in plastic moulds of 8–12 mm depths. The effcts of the nanoparticles, thickness and glycerol on the rheological properties of the fimsǰ including the Young’s modulus, creep, hardness and plasticity index were determined using nanoindentation technique. The results show that the Young’s modulus and hardness of the fims varied inconsistently with glycerol concentration and nanoparticles due probably to their isotropic nature and sensitivity to slight change in load. The plasticity index was lower for 15 µm fimǰ which absorbed 40 pNm and dissipated 0.5 pNm during loading and unloading stages, respectively. The response of the 15 µm fim to creep was higher than 16 µm and 17 µm fimsǰ and this may be consequence of lower wear at higher loads. This implies that the nanocomposite fim might be suitable for high speed transportation of packaged food.