Project Details
Projekt Print View

Texture design of food biopolymers by 3D printing for modulation of odour/flavour perception

Subject Area Biological Process Engineering
Synthesis and Properties of Functional Materials
Term from 2018 to 2022
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 405072578
 
Final Report Year 2022

Final Report Abstract

For the elucidation of texture – taste release interactions in starch-based foam structures, 3D printing technology was used in this research project. Initial modifications of the printer were conducted first to develop a suitable 3d printing method. Based on a commercial printing environment, twin extruders were integrated to enable the depositing of multiple materials (base/taste active). A twin camera system was installed to evaluate geometrical properties of printed structures as well as to identify viscoelastic induced defects. The obtained data was used to identify and to optimize cereal-based materials for printing variable textures, which was additionally aided by a rheological characterization routine. Based on this set of experiments for 50 different cereal- and starch-based materials, results showed a wide range of stability and defect behavior which was related to the printing process. In conclusion, wheat starch-egg white powder and wheat starch-soy protein mixtures were identified as suitable materials. Additionally, a NIR heater for intermediate and final stabilization of the printed structures was implemented in the printing environment. Effects of the NIR thermal stabilization method on the material properties were identified in terms of the occurrence of starch gelatinization and moisture loss. Furthermore, a moisture standardization method was developed and a mathematical model was reached to target specific final moisture content of printed structures and a material-dependent mathematical regression model was developed for the targeted attenuation of the Young’s modulus of the base material for texture modulation. Based on these printer modifications and material optimizations, the production of standardized and precise textures using 3D printing was achieved in terms of the creation of cereal-based textures using foam structures composed of 2D periodic structures, single spherical bubbles, and 3 spherical bubble configurations. Furthermore, the textural response of 3D printed cereal-based foam products was characterized in both the elastic- (linear) and plastic-deformation (non-linear) regimes. Here, porosity, moisture content, and base material’s Young’s modulus were shown to determine the foam’s hardness and Young’s modulus of the 3D printed cereal foams. Using FEM simulations and 3D printing trials, the textural relationships of 3 spherical, highly defined bubble foam configurations were successfully established and a phenomenological foam model was obtained and validated for designing 3D printing foam structures targeting specific hardness levels in the elastic regime. The non-volatile taste compounds of a sourdough bread crumb were identified and quantified. Besides salts, acids formed during sourdough fermentation, e.g. lactic and acetic acid, predominantly contribute to the taste of bread crumb. The authentic taste and odor signature of sourdough bread crumb can be reconstituted by just 10 key tastants and 11 key odorants. Based on the final taste and aroma recombinant, a LC-MS/MS quantification method was developed, that allows the quantification of all key aroma and taste compounds of the bread crumb, except of inorganic salts, in a single method that is robust, fast, and precise. For the first time, concentration gradients of breadcrumb tastants were site-specifically introduced in cereal-based food textures. Thereby, an inhomogeneous distribution of both salt and the entire taste recombinant enhanced the sensory perception compared to a homogeneous sample. In addition, it could be shown that the distribution pattern of the flavor active compounds had no influence on the sensory perception. The prerequisite for a significant increase in taste perception was that the concentration difference between the layers, with and without taste active compounds, was sufficiently strong and the total content was at a low level. The principle of this so called “sensory contrast” could be applied to develop healthier foods, as it allows e.g. salt reduction without affecting the taste of the food.

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