When freezing fruits, speed is important to minimize the deterioration of nutritional value, flavor and appearance. Do not leave fruits soaking in water to clean them for freezing. Because leaving sliced and peeled fruits sitting in the open for too long can lead to spoilage, prepare fruits for freezing in small batches, rather than all at once.
To prevent the deterioration of appearance in fruits prone to darkening, there are a number of treatments available. These include ascorbic acid, which is dissolved in water and added to the fruit, and citric acid, such as from lemon juice. For apples and other firm fruits, steaming before freezing helps prevent darkening.
Most fruits should be frozen in a syrup made from sugar and water in a ratio of 1.75:4. Adjust the sugar content according to the flavor of the fruit. Melons, for example, require only light syrups, whereas sour fruits should be frozen in more sugary syrups. Smaller fruits, such as berries, might need no syrup at all. Instead, arrange them on a tray in a single layer to freeze, and then transfer to freezer bags for freezer storage.
The best method of preparation and freezing and when to freeze depends on the type of fruits used. For best results, allow most fruits, including peaches, apples and pineapples, to ripen before freezing. However, aim to freeze berries and cherries as soon as possible.