DEFORMATION OF FOOD POWDERS BY NANOINDENTATION

Nanoindentation is a test where an indenter induces a localised deformation into a sample surface to determine its material properties, such as hardness and modulus of elasticity, at nanometre scale. The depth indentation technique was used in this study. The technique is based on the recording of the applied force as a function of penetration depth during the loading and unloading processes. In this paper, the compacted fine maize, coarse maize, and Avicel were investigated upon nanoindentation. The test was conducted so that the deformability of the food powders, which behave as viscoelastic materials, may be understood better. It was found that Avicel powder forms a stronger and more coherent junction compared to maize powders, as evidenced from their measured hardness and modulus of elasticity.