Structural-mechanical analysis of cookies produced by conventional and 3D printing techniques

Abstract

Little knowledge exists of the relationship between mechanical properties and microstructure of cookies. A cookie can be described as a solid matrix in which gas spaces of different sizes and shapes are embedded. Additive manufacturing or 3D printing has emerged as a novel method to produce cookies. The process of 3D printing is, however, significantly different from a conventional baking process. In order to assess the texture of 3D printed cookies relative to that of traditional cookies, in this study the mechanical and structural properties of cookies of different compositions and production methods were measured and analysed. Three-point bending tests were performed to determine Young’s modulus, failure stress and strain. X-ray micro-CT imaging at 5 µm pixel size was applied to characterise the 3D microstructure of the cookie samples used in mechanical testing. Of the microstructure properties, structure thickness distribution appeared to change Young’s modulus of cookies; which could be affected by the sugar and fat composition in traditional cookies. The structure of printed cookies strongly depended on both the printing method and the composition. Both particle size of the flour and the binder composition were significant. The structure: binder ratio was less effective to change structure. The final aims of this study are to combine knowledge to understand structure-property relationships of cookies incorporating observed structural properties and to construct a model capable of computing mechanical properties of foods from the microstructure and composition.status: publishe