If they are not eating blended mixtures of fruits try giving them ONE type of fruit cut in small glider hand size pieced. They might be more interested in something they can pick up.
Another way to keep them interested in their food is to let them forage for dinner. I use small hanging bird cups and put dinner in 3 dishes, fruit in one, veggie in another and their diet in the third then hang them in various places around the cage.
Sometimes they just need a change in routine to keep them interested in their food.