Mix pineapple with its juice, fructose, lemon juice and mustard in small bowl.
Place chicken on rack in shallow baking pan.
Spread pineapple mixture over each piece of chicken (approx 2 tablespoons each).
Bake for 20 minutes, then remove from oven to baste again.
Bake 20 minutes and baste again. Return to oven for final 20 minutes of baking.
Skim fat, then return to sauce pan to reheat.
Serve sauce over chicken.