Investigation of solubility of carbon dioxide in anhydrous milk fat by lab-scale manometric method

- A systematic approach examining the solubility of CO2 in milkfat is presented.
- A simple and reliable method to investigate CO2 solubility in milkfat was developed.
- Anhydrous milk fat (AMF) was fractionated into solid and liquid fractions at 21 °C.
- The presence of solid milk fat impedes the adsorption of CO2 into AMF.
- Fatty acid composition plays little role in the solubility of CO2 in molten milkfat.

This study aims to examine the solubility of CO2 in anhydrous milk fat (AMF) as functions of partial pressure, temperature, chemical composition and physical state of AMF. AMF was fractionated at 21 °C to obtain stearin and olein fractions. The CO2 solubility was measured using a home-made experimental apparatus based on changes of CO2 partial pressures. The apparatus was found to be reliable as the measured and theoretical values based on the ideal gas law were comparable. The dissolved CO2 concentration in AMF increased with an increase in CO2 partial pressure (0-101 kPa). The apparent CO2 solubility coefficients (mol kg−1 Pa−1) in the AMF were 5.75 ± 0.16 × 10−7, 3.9 ± 0.19 × 10−7 and 1.19 ± 0.14 × 10−7 at 35, 24 and 4 °C, respectively. Higher liquid oil proportions resulted in higher CO2 solubility in the AMF. There was insignificant difference in the dissolved CO2 concentration among the AMF, stearin and olein fractions in their liquid state at 40 °C.