Preheat oven to 350 degrees. In a large bowl sift together dry ingredients. Add orange peel and set aside. In a smaller bowel beat together egg substitute, sugar, vanilla and Grand Marnier. Add liquids to dry ingredients and stir until well combined. Add zucchini and nuts and combine until fully incorporated. Pour into non-stick loaf pan or pan lightly sprayed with cooking spray and floured. Bake for 50 to 60 minutes or until toothpick inserted in center comes out clean.