Thermal processing of 5-methyltetrahydrofolic acid in the UHT region in the presence of oxygen

Folates in Fruits and Vegetables: Contents, Processing, and Stability

“…Influence of pH on activation energy for 5‐CH 3 ‐H 4 folate degradation appears limited (Mnkeni and Beveridge ; Indrawati and others ), though lower activation energies are found in food media (Mnkeni and Beveridge ) or in the presence of ascorbic acid (Indrawati and others ). Under air (or with an initial oxygen concentration of 8 mg/L, corresponding to saturation of water by oxygen in ambient conditions), similar activation energies have been reported for 5‐CH 3 ‐H 4 folate degradation by Mnkeni and Beveridge (), Barrett and Lund (), Viberg and others () and Indrawati and others (), while much lower activation energies were reported by Chen and Cooper () and Ruddick and others (). This was attributed by Barrett and Lund () and by Viberg and others () to a limitation by oxygen diffusion in some of the experimental systems.…”

“…Under air (or with an initial oxygen concentration of 8 mg/L, corresponding to saturation of water by oxygen in ambient conditions), similar activation energies have been reported for 5‐CH 3 ‐H 4 folate degradation by Mnkeni and Beveridge (), Barrett and Lund (), Viberg and others () and Indrawati and others (), while much lower activation energies were reported by Chen and Cooper () and Ruddick and others (). This was attributed by Barrett and Lund () and by Viberg and others () to a limitation by oxygen diffusion in some of the experimental systems. Data on impact of oxygen itself are contradictory: slightly higher activation energies are reported for 5‐CH 3 ‐H 4 folate degradation after degassing by Barrett and Lund () and Mnkeki and Beveridge () in apple juice, but lower ones at 5.3 mg/L than at 8 mg/L initial oxygen in citrate buffer by Mnkeni and Beveridge (), while Viberg and others () determined activation energies as 107 kJ/mol for the aerobic degradation, and 62 kJ/mol for anaerobic degradation.…”

“…This was attributed by Barrett and Lund () and by Viberg and others () to a limitation by oxygen diffusion in some of the experimental systems. Data on impact of oxygen itself are contradictory: slightly higher activation energies are reported for 5‐CH 3 ‐H 4 folate degradation after degassing by Barrett and Lund () and Mnkeki and Beveridge () in apple juice, but lower ones at 5.3 mg/L than at 8 mg/L initial oxygen in citrate buffer by Mnkeni and Beveridge (), while Viberg and others () determined activation energies as 107 kJ/mol for the aerobic degradation, and 62 kJ/mol for anaerobic degradation. Activation energies for folate degradation are higher than those reported for vitamin C losses (about 30 to 40 kJ/mol) and lower than those for carotenoid degradation (>100 kJ/mol) (Renard and Maingonnat ).…”

“…Reaction rates and activation energies are reported in the reaction was only slightly faster in the presence of oxygen at 92 °C ( t 1/2 of 4.5 min compared with 7.4 min without oxygen), but much faster at 40 °C ( t 1/2 about 150 min compared with 1200 min) in connection to a higher activation energy. Viberg and others () also studied the impact of oxygen on 5‐CH 3 ‐H 4 folate at high temperatures (110 to 150 °C), with 2 initial concentrations of dissolved oxygen (6.3 to 0.3 mg/L). Delchier and others () compared folate degradation in ground spinach and green beans under strictly controlled anaerobiosis and with elevated oxygen (40 kPa).…”

Opinion of the Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) related to Calcium L-Methylfolate

“…The results indicate that the presence of oxygen accelerates degradation. Degassing treatment is recommended to keep oxidative degradation of L-5-MTHF at a minimum (Viberg et al, 1997).…”