The chelating activity on Fe2+ were significantly (P < 0.05) higher for
wheat flours extracts than for buckwheat flours extracts (Figure 4).
Since ferrous and cupric ions are the most effective pro-oxidant in food
systems (Y a m a g u c h i et al., 1988), and ferrous ions are commonly found
in food systems, high chelating activity of investigated extracts would be beneficial
in retarding metal-catalyzed oxidation (K e h r e r, 2000). The possibility
of complexing metal ions, as the antioxidant properties themselves, depends on
structure of compound, that is in the case of polyphenols (predominant flavonoids
from buckwheat and phenolic acids from wheat) implies the number and
position of OH- and CH3O-groups.