Why should folic acid be processed with amylum instead of lactose?

The chemical formula of folic acid shows that an amino group is present. This group can react with the glycosidic OH of sugars in which brown pigments are eventually formed (the Maillard reaction). Personally I would not use pure starch because this powder may not flow well and consequently the egg are irregularly filled. I then prefer mannitol powder with possibly a little (10%) Starch.