Lantmännen – a real-time study of bread during baking

To meet the high consumer demand for bread and at the same time streamline the process, the food industry needs to develop its baking techniques, but without compromising on quality. Lantmännen is a leading player in grain and food production in Sweden. As a company that works with both production and research in sustainability, quality and innovation, they have an interest in improving baking techniques and understanding how ingredients and processes affect the properties of bread. Before developing new baking methods, it is necessary to carefully investigate and gain a deeper understanding of how ingredients and baking processes affect the properties of bread. Lantmännen runs a number of different research projects in the field of food technology. In this project, they wanted to study the structure of bread in real time during baking, among other things to give the Swedish baking industry a deeper insight into how baking technology with energy-saving potential, based on microwave heating, works. Another aim was to look at how ingredient selection affects the end result. RISE, Lantmännen and Lund University collaborated in the project. The focus was on, among other things, jointly investigating how two different baking techniques, one with microwave convection and one with conventional convection baking, affect the microstructure and quality of the bread, which requires advanced technology and carefully designed experiments.

The choice fell on X-ray microtomography in synchrotron

 Analyzing the structure of bread in real time is difficult because the baking process itself is complex. Traditional analysis methods, where samples are taken for analysis at different times, would interrupt the baking process and make it impossible to track changes in an individual sample throughout the baking process. Therefore, the study ended up using synchrotron X-ray microtomography to examine the structure of bread. X-ray microtomography (μCT) is a non-destructive method that makes it possible to image the microstructure of bread. With traditional μCT, analyses can be performed in a static state, but in order to be able to image the bread in real time during the baking process, with the required time resolution, the X-ray flux of a synchrotron facility was needed. Therefore, the research team chose to use SRμCT, Synchrotron Radiation Micro-Computed Tomography, an advanced X-ray technique using synchrotron radiation that creates high-resolution 3D images of microscopic structures. In this project, this was done by improving previously developed measurement methods, in an X-ray tomography environment with high spatial and temporal resolution, measuring how the cell structure of bread changes over time. Baking bread using microwave heating makes it possible to speed up production, and in some cases save energy, but the rapid baking also poses challenges in analysis. To meet these challenges, the research team had to modify a commercially available oven, and also chose to perform the experiments at the world's fastest microtomography facility, TOMCAT at the Paul Scheller Institute in Switzerland.

To promote innovation and strengthen the Swedish bakery industry 

During the experiments, variations were used based on a basic recipe for a bread roll as chosen by Lantmännen. A representative from Lantmännen participated during the tests, which helped to ensure quality and repeatability during implementation. Based on a wheat-based recipe, the ingredients were varied by adjusting the amounts of salt, oat flour, wheat fiber and whole grains. The researchers also experimented with adding DATEM and lipase. DATEM is an emulsifier and lipase is an enzyme, both of which are used to improve the texture of bread dough. A project sub-goal was met when the research team was able to image the entire baking process, both with microwave and convection. By following the development of key parameters, such as cell wall thickness, average pore size and porosity, they gained deeper insight into the differences between the two baking methods (combined microwave and convection baking and conventional baking, respectively). For example, it turned out that combination baking gave smaller variations in the parameters that the researchers studied. Another observation was that the addition of the dough improvers lipase and DATEM seemed to affect pore development in different ways in conventional convection baking. In the long run, there is hope that insights from this type of measurements will contribute to innovations and strengthen the Swedish bakery industry. This study provides some insights, but Lantmännen continues to run more research projects to develop the food industry's baking methods.

Facts 
What is SRμCT?

Synchrotron Radiation Micro-Computed Tomography, SRμCT, is an advanced method for X-ray-based 3D imaging that uses synchrotron X-rays, the intense form of light generated in synchrotron facilities, to create high-resolution images of microscopic structures. The technology is used to scan and analyze materials in detail, without having to destroy or alter the sample.

How and where was Lantmännen's study conducted?

The experiment was conducted in a test environment in the form of an Electrolux combination oven that was modified to replace the pulsed power supply (1 kW on/off) with one that delivers continuous microwave power (between 0.2 and 1 kW). This was necessary to be able to image the entire baking process in combined microwave baking. The imaging was performed with SRμCT at the TOMCAT beam tube, Paul Scherrer Institute (PSI) in Switzerland. The scans were performed with a resolution of 11 μm per pixel and a time resolution of 1 second per 3D scan, with the focus on the center of the bread bun.