Model studies on the stability of folic acid and 5-methyltetrahydrofolic acid degradation during thermal treatment in combination with high hydrostatic pressure.
Stability of folic acid and 5-methyltetrahydrofolic acid in phosphate buffer (0.2 M; pH 7) toward thermal (above 65 degrees C) and combined high pressure (up to 800 MPa)/thermal (20 up to 65 degrees C) treatments was studied on a kinetic basis. Residual folate concentration after thermal and high pressure/thermal treatments was measured using reverse phase liquid chromatography. The degradation of both folates followed first-order reaction kinetics. At ambient pressure, the estimated Arrhenius activation energy (E(a)) values of folic acid and 5-methyltetrahydrofolic acid thermal degradation were 51.66 and 79.98 kJ mol(-1), respectively. It was noticed that the stability of folic acid toward thermal and combined high pressure thermal treatments was much higher than 5-methyltetrahydrofolic acid. High-pressure treatments at room temperature or higher (up to 60 degrees C) had no or little effect on folic acid. In the whole P/T area studied, the rate constant of 5-methyltetrahydrofolic acid degradation was enhanced by increasing pressure, and a remarkable synergistic effect of pressure and temperature on 5-methyltetrahydrofolic acid degradation occurred at temperatures above 40 degrees C. A model to describe the combined pressure and temperature effect on the 5-methyltetrahydrofolic acid degradation rate constant is presented.
Department of Food Technology, College of Agriculture, Cantho University, Cantho, Vietnam.
Minh Thuy
MT
Nguyen
Indrawati
M
M
Hendrickx
D004355:Drug Stability; D005492:Folic Acid / Q000737:chemistry*; D006358:Hot Temperature; D006874:Hydrostatic Pressure; D007700:Kinetics; D008433:Mathematics; D008956:Models, Chemical; D013763:Tetrahydrofolates / Q000737:chemistry*; D013816:Thermodynamics
D013763:Tetrahydrofolates; D005492:Folic Acid; C005984:5-methyltetrahydrofolate