Deamidation kinetics of casein precipitated by carbon dioxide compared with commercial caseinates

Casein precipitated by carbon dioxide (CO2-casein), and commercial sodium a nd calcium caseinates (1% w/v in water) were thermally deamidated at pH 8 f ar up to 96h at 85, 100, and 115 degrees C. CO2-casein displayed the highes t overall extent of deamidation at 100 and 115 degrees C after 32 and 24h, respectively, while there was no difference at 85 degrees C. Structural dif ferences between CO2-casein and the commercial caseinates may account for t he difference in deamidation. Deamidation kinetics were apparent first-orde r with respect to concentrations of the amides, asparagine and glutamine. R eaction rate constants and Arrhenius parameters were comparable from regres sion modeling.