Abstract
Hydrogen peroxide, individually, or in combination with potassium thiocyanate, inactivated milk folic acid (free and total) significantly. Addition of hydrogen peroxide to milk caused inactivation of folic acid added to milk and this inactivation was prevented by the addition of potassium thiocyanate. Potassium thiocyanate
per se did not inactivate folic acid in milk. Lactoperoxidase, in the presence of hydroperoxides or GSH-Mn(II), was also found to degrade folic acid
in vitro. Potassium thiocyanate and high concentrations of hydroperoxides inhibited this degradation. The role of lactoperoxidase, hydroperoxides and potassium thiocyanate (antimicrobial system) on the folic acid stability in milk is discussed.