Résumé
Authorities have called for salt content to be reduced in various food products. Cheese appears to be one of the most targeted products. In order to understand how to reduce salt content in model cheeses without modifying salty perception, the interactions between in-mouth sodium release and cheese composition and structure have to be studied. . The current study was conducted to determine how the release of aroma compounds and sodium ions could be modified by the structure and the composition of model cheese (lipid/protein ratio, sodium content ...). This will be done by in vivo and in vitro approaches. 23Na Nuclear Magnetic Resonance (NMR) spectroscopy was used to study the mobility and the environment of the Na+ ions in model cheeses of different compositions. Diffusion and partition coefficients of sodium ions between cheese and water were measured in vitro. Aroma release was then investigated in vivo by Atmospheric Pressure Chemical Ionization Mass Spectrometer (APCI-MS) during cheese consumption. Additionally, the different microstructures of model cheeses were analysed with Confocal Laser Scanning (CLS) microscopy. The NMR spectroscopy turned out to be an accurate method to quantify the total amount of sodium in the model cheeses. Moreover, this spectroscopy gave information on the environment of the Na+ ions, which is more specifically ordered in the hardest model cheese than in the softest one. This aspect can be linked to the denser microstructure observed with CLS microscopy in the hard model cheese. Besides, the study of the flavoured model cheeses with APCI-MS showed that the aroma compounds were more released from the hardest cheese during consumption. Thus, differences in sodium and aroma release appear to be mostly dependent on cheese micro-organisation.