European Food Research Technology vol:223 issue:3 pages:325-331
Isothermal and isobaric isothermal degradation kinetics of (6R,S) 5-formyltetrahydrofolic acid (5-CHOH4PteGlu) was studied at different pH levels in the temperature range from 80 to 110 oC and different pressure-temperature combinations (100 to 800 MPa and 30 to 70 oC).
The thermal degradation of 5-CHOH4PteGlu followed first order kinetics at all pH levels (in the range of pH 3-9.2) studied. 5-CHOH4PteGlu at pH 7-9.2 was quite stable up to 5-7 hr of heating at 80 °C but less stable in more acidic conditions (pH 3.38 and pH 5).
Pressure-temperature degradation of 5-CHOH4PteGlu could be adequately described by a first order reaction. In the whole pressure-temperature area studied, the degradation rate constants of 5-CHOH4PteGlu were enhanced by increasing pressure or increasing temperature. Significant reductions in 5-CHOH4PteGlu concentration were noticed when pressures above 400 MPa were combined with temperatures above 40 oC. A model to describe the effect of combined pressure and temperature on the 5-CHOH4PteGlu destruction rate constant was presented.