First assessment of diffusion coefficients in model cheese by fluorescence recovery after photobleaching (FRAP).
Mass transfer of solutes like salt, moisture and metabolites, is very important for the final quality of cheese, through the control of the brining and ripening processes. Numerous studies have reported salt and water transfer properties in cheese, but few have dealt with other solutes. Moreover, most diffusion coefficients have been obtained by macroscopic and destructive methods. We developed the fluorescence recovery after photobleaching (FRAP) technique on a confocal microscope to measure in situ and at the microscopic scale diffusion properties inside cheese. A model matrix based on ultrafiltrated milk was used. FITC-dextran molecules were chosen as models of migrant solutes. Diffusion coefficients were estimated with a modelling approach which takes into account diffusion during the bleach phase. The FITC-dextrans (4 and 20 kDa) were able to migrate in the proteinic network, but their mobility was 2.2-3 times lower than in water, depending on their size.
['Floury|J|J|', 'Madec|M-N|MN|', 'Waharte|F|F|', 'Jeanson|S|S|', 'Lortal|S|S|']
D000818:Animals D002417:Cattle D002611:Cheese D003911:Dextrans D004058:Diffusion D016650:Fluorescein-5-isothiocyanate D036681:Fluorescence Recovery After Photobleaching D007700:Kinetics D008892:Milk D008962:Models, Theoretical D012996:Solutions
Diffusion Cheese FRAP Confocal microscopy