Résumé
Reducing salt content without affecting acceptability is a main challenge of food industries. One way could be to increase the mobility of sodium ions in food matrix and their release during consumption. This study consists in a multimodal approach to understand the effect of changes in composition of model cheeses on the mobility of salt (NaCl). Six flavoured model cheeses have been formulated (three lipid/protein ratios, two NaCl contents) and their microstructures were characterised by confocal laser scanning microscopy. At molecular level, sodium mobility in model cheeses was analysed by 23Na Nuclear Magnetic Resonance (NMR) spectroscopy. At macroscopic level, sodium release in the water phase was followed by measuring partition coefficients. Sodium ions were then quantified by High-Performance Liquid Chromatography (HPLC). 23Na NMR spectroscopy turned out to be an accurate method to quantify sodium and highlighted a fraction of ‘bound’ sodium in all the model cheeses. Nonetheless, the mobility of the sodium ions was different according to the cheese composition. Indeed, cheeses with the highest lipid/protein ratio (lowest protein content) showed the highest mobility of sodium ions. This was linked to differences in fat/protein repartition observed in microscopy. The changes in composition also caused significant differences in partition coefficients of sodium ions, with the highest sodium release for the cheeses with the highest lipid/protein ratio. This multimodal approach shows that cheese composition affects sodium mobility and release for in vitro conditions. Further studies will be led concerning the in vivo study of sodium release during the consumption of model cheeses. All these results could be used for formulation of products with a lower salt content.