Fractal character of the pore structure of dehulled rapeseed cake based on scanning electron microscopy image analysis

The fractal characteristics of pore structures and the effects of pressing pressure on the pore structures of rapeseed cakes were investigated using dehulled rapeseed cakes formed under uniaxial compression as an object of study. The microstructures of dehulled rapeseed cakes under six pressing pressures were measured by using scanning electronic microscope and Image-pro image analyzer. Fractal dimensions of pore section edges and pore size distributions were measured by the slit island process. The empirical formulas of fractal dimensions of pore section edges and pore size distributions as functions of pressing pressure were developed by regression analysis. The results showed that the fractal feature of the pore in dehulled rapeseed cake was remarkable, the higher the fractal dimension value, the more irregular the pore section edges and the wider the pore size distributions, the fractal dimension increased with the increase of pressing pressure, the linear equations of fractal dimensions as functions of pressing pressures were satisfyingly obtained.