DETERMINATION OF THE APPARENT FRACTAL DIMENSION OF THE FORCE-DISPLACEMENT CURVES OF BRITTLE SNACKS BY FOUR DIFFERENT ALGORITHMS

The apparent fractal dimension of digitized experimental force-displac ement curves of cheese balls and Zwiebacks at various levels of water activity were determined with the Richardson, Minkowski, Kolmogorov an d Korcak algorithms. All four, but especially the first three, produce d a consistent dimension despite the fact that the curves themselves w ere nor truly fractal. These calculated dimensions were effective jagg edness measures and could be used interchangeably to monitor moisture sorption effects on the shape of force-displacement relationships. The apparent dimension versus water activity plot had a sigmoid form whic h was characterized by a shifted Fermi equation. The center point of t he jaggedness loss as well as its span was revealed from the magnitude of the equation's constants or directly from the plot.