Detection method for salt content and spatial distribution in bread using CLSM

Abstract

A major health concern today is the increasing intakes of salt from many of the food products consumed every day. The high salt content contributes to health issues like raised blood pressure and increased risk for cardiovascular disease. A national project to reduce the amount of salt in several food products in the purpose to increase the health in the population started in the spring of 2017. One of the food products that is included in the project is bread products where different types of spatial salt distribution will be evaluated. The purpose is to reduce the amount of salt without effecting the taste and functionality of the bread. To verify the tested distribution methods a method has been developed for detection of salt distribution. The method has been developed with confocal microscopy and the sodium sensitive probe CoroNa Green. The confocal microscope is well used in food research and is a good tool to study bread due to the ability to created 3D-projections. Model systems with different complexity have been studied to find limitations and optimized conditions for the probe. The studied systems have been: salt solutions, gelatin gels, dough and bread. The influence of different settings on the microscope and the function of the probe have been evaluated. The result shows that the probe works well in all systems and that the method is most likely to be able to determine changes in the salt concentration within a sample. 3D-projections have successfully been used to study bread where the structure is clearly shown and it has potential to also visualize inhomogeneous salt distribution. The main parameters to keep in mind are that the probe is sensitive for heating, the diffusion and affinity to the sample and between different components. It is also important to use the same application method, concentration and incubation time for all samples that shall be compared to each other. These parameters influence the responding fluorescent signal and might provide a false result if they are varied between different replicates.