Chocolate is a food gender with very specific rheological and sensory characteristics, which poses a challenge to the development of functional formulations due to the impact that the addition of various ingredients have on the product. The goal of this study was to develop sucrose-free chocolate formulations employing a mixture design to add fibres as partial substitutes for cocoa butter. The effects of the combination of different contents of inulin, β-glucan concentrate and cocoa butter on Casson plastic viscosity, Casson shear stress and the sensory characteristics of chocolate were investigated. An increase from 0 to 10 g/100 g chocolate in the inulin and the β-glucan concentrate contents, with the corresponding reduction in the amount of cocoa butter made the final product more viscous and more resistant to flow. The effects were more pronounced for β-glucan. The substitution of up to 50% of the formulation cocoa butter resulted in products with good acceptance. The least accepted product, with a mean score of 6.4 in a scale from 0 to 10 had the maximum concentration of β-glucan (10 g/100 g). The descriptive analysis of the Flash profile of this sample characterized it as more adherent and adhesive, with a non-characteristic chocolate taste