Diffusivity and solubility of CO2 in dense solid food products

A cheap and easy to handle methodology was adapted to achieve the measurement of CO2 diffusivity within solid food matrices. This methodology was tested on real food products with different composition (cooked ham, butter and processed cheese). Local distribution profiles, measured using a customized chemical titration, permitted in the same time to determine CO2 solubility and identify diffusivity values within the different kinds of food studied. Values of solubility were found of 2.09 ± 0.10 × 10−7 mol kg−1 Pa−1 for cooked ham, 3.52 ± 0.09 × 10−7 mol kg−1 Pa−1 for processed cheese and 3.81 ± 0.15 × 10−7 mol kg−1 Pa−1 for butter, at 22 °C. Validity of Henry's law to predict dissolved concentration of CO2, indispensible prerequisite to diffusivity identification, was assessed on a large range of CO2 partial pressure (0-100%) in the three products tested. Values of diffusivity, varying from 0.57 × 10−9 m2 s−1 for cooked ham to 1.42 × 10−9 m2 s−1 for butter with an intermediate value of 0.88 × 10−9 m2 s−1 for processed cheese, tended to be closely connected to the composition of the matrix (fat, protein and water contents).