Some fruits darken when exposed to air and during freezing. This darkening may be lessened or prevented by treating fruit with an anti-darkening agent at the time it is peeled and sliced, or as the fruit is packed for freezing, or at both times.
To prevent darkening of fruit, use one of the following anti-darkening agents:
- Ascorbic acid crystals – These are the most economical because of the small amount used. Ascorbic acid crystals are available in drugstores, health food stores and sometimes in stores carrying canning supplies.
- Ascorbic acid tablets – These may be used, but they are difficult to crush and dissolve. Fillers in the tablets may make the packing syrup cloudy.
- Fruit Fresh® – This is a commercial product which may be used by following instructions on the package or the guidelines below.
- Salt or lemon juice – Either of these may be used but are not as effective as Fruit Fresh® or ascorbic acid crystals. Salt or lemon juice are only suitable to treat fruit as it is peeled and sliced.
- Steam – For fruit such as apples that will be cooked after freezing, steam may be used to prevent discolouration. Steam small quantities of fruit at a time, just until fruit is heated through.