Résumé
This study aims to generate new kinetic data on 4 folate forms, namely folic acid (FA), 5-methyl-tetrahydrofolate (5MTHF), 10-formylfolic acid (10FFA) and tetrahydrofolate (THF) in the same conditions: model media at three temperatures (60°C, 80°C, and 100°C) and three pH values (3, 5, and 7). For the four forms, degradation could be described using a first-order model. At 100°C and pH 3, rates were 2.8 × 10−2, 1.6 × 10−2, 1.8 × 10−3, and 4 × 10−5 min−1 for 5MTHF, THF, 10FFA and FA respectively. Therefore, the reactivity could be modulated by a factor of 2, 10, and up to 200-fold for folic acid. pH increase had a positive effect on retention for THF and FA and has the lowest impact on 5MTHF degradation. Product formation from 5MTHF and 10 FFA were studied by multiresponse modeling. Both vitamers generated intermediary products that accumulated differently as a function of pH. These results give comprehension and kinetic insights into folate degradation during food processing from the formulation (pH lever) to the process (temperature lever).