Browsing by Person "Vidal, Leonhard Maria"

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Micro-scale shear kneading: Gluten network development under multiple stress-relaxation steps and evaluation via multiwave rheology
(2022) Vidal, Leonhard Maria; Braun, Andre; Jekle, Mario; Becker, Thomas
To evaluate the kneading process of wheat flour dough, the state of the art is a subsequent and static measuring step on kneaded dough samples. In this study, an in-line measurement setup was set up in a rheometer based on previously validated shear kneading processes. With this approach, the challenge of sample transfer between the kneader and a measurement device was overcome. With the developed approach, an analysis of the dynamic development of the dough is possible. Through consecutive stress–relaxation steps with increasing deformation, a kneading setup in a conventional rheometer is implemented. Fitting of the shear stress curve with a linearization approach, as well as fitting of the relaxation modulus after each kneading step, is a new way to evaluate the matrix development. Subsequently, multiwave rheology is used to validate the kneading process in-line. The shear kneading setup was capable of producing an optimally developed dough matrix close to the reference kneading time of 150 ± 7.9 s (n = 3). The linearization approach as well as the power-law fit of the relaxation modulus revealed gluten network development comparable to the reference dough. With this approach, a deeper insight into gluten network development and crosslinking processes during wheat flour dough kneading is given.
Microscopic analysis of gluten network development under shear load—combining confocal laser scanning microscopy with rheometry
(2023) Vidal, Leonhard Maria; Ewigmann, Hans; Schuster, Clemens; Alpers, Thekla; Scherf, Katharina Anne; Jekle, Mario; Becker, Thomas
A comprehensive in‐situ analysis of the developing gluten network during kneading is still a gap in cereal science. With an in‐line microscale shear kneading and measuring setup in a conventional rheometer, a first step was taken in previous works toward fully comprehensible gluten network development evaluation. In this work, this setup was extended by an in‐situ optical analysis of the evolving gluten network. By connecting a laser scanning microscope with a conventional rheometer, the evaluation of the rheological and optical protein network evolution was possible. An image processing tool for analyzing the protein network was applied for evaluating the gluten network development in a wheat dough during the shear kneading process. This network evaluation was possible without interruption or invasive sample transfer comparing it to former approaches. The shear kneading system was able to produce a fully developed dough matrix within 125% of the reference dough development time in a classical kneader. The calculated network connectivity values from frequency testing ranged over all samples was in good agreement with traditional kneaded wheat dough just over peak consistency.