Browsing by Person "Fahmy, Ahmed Raouf"

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Four-dimensional (4D) printing of dynamic foods - definitions, considerations, and current scientific status
(2023) Fahmy, Ahmed Raouf; Derossi, Antonio; Jekle, Mario
Since its conception, the application of 3D printing in the structuring of food materials has been focused on the processing of novel material formulations and customized textures for innovative food applications, such as personalized nutrition and full sensory design. The continuous evolution of the used methods, approaches, and materials has created a solid foundation for technology to process dynamic food structures. Four-dimensional food printing is an extension of 3D printing where food structures are designed and printed to perform time-dependent changes activated by internal or external stimuli. In 4D food printing, structures are engineered through material tailoring and custom designs to achieve a transformation from one configuration to another. Different engineered 4D behaviors include stimulated color change, shape morphing, and biological growth. As 4D food printing is considered an emerging application, imperatively, this article proposes new considerations and definitions in 4D food printing. Moreover, this article presents an overview of 4D food printing within the current scientific progress, status, and approaches.
Multi‐scale dough adhesion analysis: Relation between laboratory scale, pilot scale and human sensory
(2023) Vogt, Ulrike Therese; Kwak, Ju Eun; Fahmy, Ahmed Raouf; Laukemper, Rita; Henrich, Alexander; Becker, Thomas; Jekle, Mario
Undesired dough adhesion is still a challenge during the production of baked goods. There are various methods for determining the adhesive texture properties of dough. In the majority of scientific papers, dough stickiness is measured analytically by the force‐distance recording of dough detachment. In this study, we describe a new multi‐scale approach to compare dough adhesion phenomena in a laboratory, pilot sale and human sensory assessment. In it, the adhesive material properties of dough were investigated using a pilot scale toppling device representing dough adhesion behavior in the production process, in the laboratory by texture analysis with the Chen–Hoseney method and furthermore with a new, implemented non‐oral human sensory analysis. To simulate different dough adhesion behavior, the dough mechanical and adhesion properties were varied by applying dough‐modifying enzymes and different dough storage times. The structural changes in the different wheat dough system were compared by rheological characterization. By characterizing the different adhesion phenomena of the doughs, the sample with bacterial xylanase showed the highest values after 80 min of storage time in all three methods. Correlation analysis revealed a strong relationship between the detachment time (pilot scale) and human sensory assessment attributes (Force R = 0.81, Time R = 0.87, Distance R = 0.92, Stickiness R = 0.80) after 80 min of storage time. Even though human sensory assessment showed limits in the detectability of differences in dough adhesion behavior compared to the Chen–Hoseney method, it was better suited to predict machinability.
Texture modulation of starch‐based closed‐cell foams using 3D printing: Deformation behavior beyond the elastic regime
(2022) Fahmy, Ahmed Raouf; Jekle, Mario; Becker, Thomas
3‐dimensional printing is a novel processing method used for the design and manipulation of food textures. The systematic characterization and modulation of 3D printed food textures is imperative for the future design of sensory profiles using additive manufacturing. For 3D printed closed‐cell food foams, the clarification of the deformation behavior in relation to design parameters is of interest for the processing of customized food textures. For this reason, we studied the deformation behavior of 3D printed and thermally stabilized closed‐cell starch‐based foams beyond the elastic regime. Periodic spherical bubble configurations at different porosity levels were used to modulate the deformation behavior of the printed foams. From a processing perspective, the integration of in‐line thermal stabilization was used to eliminate post‐processing and to control the moisture content of the starch‐based system. Compression analysis combined with FEM simulations were performed to characterize the strain rate dependency of textural properties, the stress relaxation, and the foam's stress–strain behavior with respect to the design porosity and bubble distribution. Results showed that the stress relaxation is solely dependent on cell wall properties while different stress–strain regimes showed distinct dependencies on design parameters such as bubble size and distribution. Consequently, the precise control of the large deformation behavior of foods using 3D printing is challenging due to the superposition of structural and geometrical dependencies. Finally, through the presented approach, the structure‐deformation relations of 3D printed closed‐cell food structures are adequately described.