CONICET | Buscador de Institutos y Recursos Humanos

The surface area and volume of food material are parameters of great importance in the food engineering field, fundamentally in many processes involving heat and mass transfer. However, it is very difficult to obtain these parameters experimentally, due to natural irregularity and variation of size and shape, even for a same type of food. Only few cases must deal with true regular shapes. Therefore, the surface area and volume do not have an analytical equation to determine their actual values. As a solution, it has been widely used to approximate the true irregular geometry to regular shapes as infinite slab, ellipse, infinite and finite cylinders, parallelepiped, sphere and spheroids. The aim of this work is to develop a procedure to estimate the surface area and volume of an irregular food sample using image digital processing and finite element method (FEM). To validate the developed method, the surface area and volume of a whole beef piece were determined. Different images of successive parallel transversal cuts along the principal axis of semitendinous muscle were obtained using an IP camera. The images were processed using CAD techniques. A numerical model was implemented using FEM commercial software which was used to estimate the surface area and volume of the sample. To validate the results the volume of different meat samples were experimentally determined. The surface area was not measured because of its difficulty. The relative error between experimental and calculated volume was less than 5%, showing the goodness of the implemented procedure. The method presented in this paper has proved to be adequate to estimate the surface area and volume of irregular foods, notwithstanding the method is destructive. The results suggest that the developed procedure can be used to obtain general expressions of the involved parameters of irregular geometries depending on its characteristics dimensions.