The objective of the present work was to developed different formulations of functional beef burguer with the addition of wheat fiber with different diameters and evaluate the effect of fibers with different size and evaluate the effect of fibers in structural and physical properties of the product. The fibers were denominated Fiber 200 (250 mm in length and 25 mm in thickness) and Fiber 600/30 (35 mm in length and 20 mm in thickness) and adding central composite design followed a 2². The addition on fibers altered the physical and structural properties of burgers developed. Significant differences were observed (p < 0.05) in the physical properties of the burgers developed from the change of particle size of wheat fiber and concentrations. Comparing the observations found in microscopy with the results of evaluations of shear force and cooking losses, it is conclude that there is a relationship between some properties with their microscopic structures. The best results were found for the F2 indicating Fiber 200 (large particles) to allow maintenance of close texture pattern F1 (without fibers) and lower cooking loss when compared to the added fiber product of low particle size (Fiber 600/30). The mixing proportions of the fibers tested were not a viable alternative due to the increase in the hardness of the product.