PREPARATION OF CASEIN USING CARBON-DIOXIDE

The effects of pressure, temperature, residence time, and mass of skim milk on some characteristics of casein, prepared by precipitation wit h high pressure CO2, were examined in a batch reactor. For a 500-g mil k sample, precipitation occurred at pressures >2760 kPa and temperatur es >32 degrees C. Residence time was not significant and was held at 5 min. Yields were maximum at 2750 to 5520 kPa and at 38 to 49 degrees C for a 500-g milk sample. The resulting whey had a pH of 6.0. The cas ein product had an acceptable appearance and had greater solids, ash, and Ca contents than commercial acid caseins. Particle size distributi on studies showed that the mean particle size was sensitive to precipi tation pressure and temperature and was similar to that of acid casein s produced under laboratory conditions. The HPLC studies of the casein and whey fractions showed that precipitation by CO2 did not result in fractionation of casein or whey proteins to their component proteins.