Salt and aroma compound release in model cheeses in relation to their mobility.

Physicochemical properties (partition and diffusion coefficients) involved in the mobility and release of salt and aroma compounds in model cheeses were determined in this study. The values of NaCl water/product partition coefficients highlighted interactions between proteins and NaCl. However, these interactions were not modified by the product composition or structure. On the contrary, model cheese composition and structure influenced NaCl diffusion and both partition and diffusion for aroma compounds. Analysis of in-nose measurements of aroma release during eating, with regard to physicochemical properties, showed that product and aroma properties partly contributed to flavor release. Depending on the model cheese composition, structure and firmness, physicochemical properties, food breakdown, and chewing behavior can lead to different aroma release profiles. Finally, a discussion of all the results with regard to salt and flavor perception of the model cheese showed that both physicochemical and cognitive mechanisms contributed to perception.

Diffusion of aroma compounds in stirred yogurts with different complex viscosities.

To better understand aroma release in relation to yogurt structure and perception, the apparent diffusivity of aroma compounds within complex dairy gels was determined using an experimental diffusion cell. Apparent diffusion coefficients of four aroma compounds (diacetyl, ethyl acetate, ethyl hexanoate, and linalool) at 7 degrees C in yogurts (varying in composition and structure) ranged from 0.07 x 10 (-10) to 8.91 x 10 (-10) m (2) s (-1), depending on aroma compounds and on product structure. The strong effect of yogurt fat content on the apparent diffusivity of hydrophobic compounds was revealed (15-fold and 50-fold decreases in the apparent diffusion coefficient of linalool and ethyl hexanoate, respectively). Protein composition seemed to have a greater effect than that of mechanical treatment. However, variations in the apparent diffusion coefficient for the considered products remained limited and cannot completely explain differences in flavor release and in perception that were previously observed.