1. Sift together flour, sugar, baking powder and salt in a large bowl.
2. Add the milk, egg yolks and canola oil and mix well.
3. Beat the egg whites in a small metal or glass mixing bowl until stiff peaks form.
4. Mix the pineapple pieces into batter.
5. Fold in the beaten egg whites.
6. Cook the waffles according to waffle iron manufactures recommendations.