Fluorescence recovery after photobleaching as a probe of diffusion in starch systems

The diffusion coefficients of dextran probes of various molecular weights in starch solutions over a wide concentration range were carried out using fluorescent recovery after photobleaching (FRAP), combined with a confocal microscope and tracer probe diffusion. The technique is simple to implement and can be carried out using increasingly common microscopy apparatus, giving access to a wide variety of new structural and kinetic information. The data can be rationalized in terms of the effects of probe molecular weight and on matrix starch concentration and structure. This provides a new tool to investigate the behavior of systems where starch is an ingredient that contributes to the processing and textural properties of food.