Fruits are also candidates for blanching as they, too, are susceptible to deterioration caused by enzymes. However, a more effective alternative to blanching fruit is to preserve color, flavor, texture, and nutrients by adding an antioxidant, such as ascorbic acid or sugar syrup, before freezing. This technique deactivates enzymes and blocks oxidation.
Sugar also serves at least two other important functions. When it comes to freezing, slightly ripe fruits are better than ripe ones, and sugar's sweetening power helps mask the acidic flavor in unripe fruits. Sugar also lowers the freezing point and thus helps prevent the formation of large ice crystals that could rupture the fruits' cell walls and membranes. Punctured cells are undesirable because flavorful juices would seep out, making the texture mushy when the mixture thaws.