Mechanism and related kinetics of 5-methyltetrahydrofolic acid degradation during combined high hydrostatic pressure-thermal treatments.

The mechanism and kinetics of the degradation of 5-methyltetrahydrofolic acid during thermal and combined high pressure-thermal treatments in an aqueous solution were investigated. In a first approach the degradation was described by a first-order kinetic model using single-response modeling, and the combined pressure-temperature dependence of the resulting degradation rate constants was empirically described. To obtain a mechanistic insight, degradation products were purified and identified by LC-MS and NMR. Quantification of an s-triazine derivative, 5-methyldihydrofolic acid, and p-aminobenzoyl-l-glutamate as predominant degradation products at atmospheric pressure resulted in elucidation and kinetic characterization of the folate degradation mechanism by Bayesian multiresponse modeling. The postulated mechanism was evaluated at elevated hydrostatic pressure. On the basis of the pressure and temperature dependence of the reaction rates, some degradation reactions were either accelerated or decelerated upon application of pressure. Multiresponse kinetics can be a valuable tool to assess the impact of high hydrostatic pressure and other processing techniques on nutrients, and incorporating mechanistic insights can advance the current kinetic approach for process optimization.