In large bowl, prepare icing mix following package instructions and adding lemon extract. Thoroughly stir in icing color.
Arrange half the angel food cake cubes at the bottom of large glass bowl. Sprinkle evenly with half the strawberries and half the blueberries. Spread half of the whipped icing on top. Continue layering with remaining ingredients.
Using raspberries, create a border around top of trifle. Garnish with whole strawberry. Cover and refrigerate until thoroughly chilled, about 3 hours.