Thermal destruction of folacin in microwave and conventional heating

Folacin derivatives were found to vary greatly in thermal stability. It is worth mention that pteroylmonoglutamic acid (PGA), the folate used therapeutically and in food supplementation, was extremely stable to heat under the experimental conditions, that is, at 100 degrees C. in neutral solution. Under these conditions, 5-formyl-THFA also exhibited marked stability; neither form was affected significantly by microwave radiation. In view of the increasing data indicating the abundance of 5-methyl-THFA and other derivatives of THFA in foods, the thermal lability of these forms was especially interesting. THFA was found to be an extremely labile folate, while 5-methyl-THFA had intermediate stability among the forms tested. Microwave heating of 5-methyl-THFA resulted in a faster rate of degradation than conventional heating at the same temperature. The mechanism of this action needs further research.