This recipe, from the molecular gastronomy cooking kit Cuisine R- Evolution, employs an emulsification technique. Using soy lecithin, a lemon juice mixture is transformed into edible foam.
2/3 cup water
2/3 cup lemon juice
2 grams soy lecithin (packaged in the Cuisine R-Evolution kit, or available at health food stores)
Combine lemon juice, water and soy lecithin in a bowl.
Using a hand blender or an egg beater, mix the ingredients together until a foam is formed. Using a spoon, remove the foam and place on top of your dish.