Microscopic analysis of gluten network development under shear load-combining confocal laser scanning microscopy with rheometry

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.

Automated summary

This study presents a new experimental system for analyzing the development of gluten network during kneading. By connecting a laser scanning microscope with a conventional rheometer, the rheological and optical protein network evolution could be evaluated simultaneously. An image processing tool was used to analyze the gluten network development in a wheat dough without interrupting or invasive sample transfer. The shear kneading system was capable of producing 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 were in good agreement with traditional kneaded wheat dough just over peak consistency.