Frozen Dessert Frozen desserts are not only crystalline systems, but usually are both suspensions and foams as well. When cream is used in the mix, an emulsion is also involved. Frozen desserts contain solutes dissolved in water to form a solution. This lowers the freezing point and the amount the freezing point is lowered is dependent on the concentrtion and extent of ionization of the solutes. Butter, milk, cocoa and corn syrup are commonly used as both crystal interfering agents and flavoring.
Candy begins when the water or other liquid is supersaturated with the solute, usually sucrose.
Supersaturation occurs when more sugar is present than can be dissolved at that temperature. By heating the solution above the boiling point of water the solute concentration becomes greater. A supersaturated solution is formed when this solution, after heating to a high temperature, is allowed to cool undisturbed. Upon cooling the sugar recrystallizes into several small crystals or forms one large amorphous mass. For crystallization to occur, nuclei must form and solute must be added from the solution to these nuclei.