When harvested, fresh fruit continues to undergo chemical changes which can cause spoilage and deterioration of the product. Therefore, these products should be frozen as soon after harvest as possible and at their peak degree of ripeness.
Fresh produce contains chemical compounds called enzymes which cause the loss of color, loss of nutrients, flavor changes, and color changes in frozen fruit. In fruit, these enzymes can cause brown colors and the loss of vitamin C. The most common control chemical is ascorbic acid (vitamin C). Ascorbic acid may be used in its pure form or in commercial mixtures with sugars.
To maintain top quality, frozen fruit should be stored at 0 degrees F or lower. Most frozen fruit maintains high quality for 8 to 12 months. Unsweetened fruit loses quality faster than fruit packed in sugar or sugar syrups.
Use high quality containers which are moisture and vapor proof so that moisture can be kept in the product and air kept away from it. Rigid containers made of plastic are suitable for all packs and are especially good for liquid packs.
There are three ways to pack fruit for freezing: sugar pack, syrup pack, and unsweetened pack.
Sugar pack: sprinkle the required amount of sugar over the fruit. Gently stir until the pieces are coated with sugar and juice.
Sugar syrup: dissolve the needed amount of sugar in cold water. Stir the mixture and let stand until the solution is clear.
To freeze fruit
- Wash and sort fruit carefully and discard parts that are of poor quality.
- Prepare fruit as you will use it.
- Check the chart for fruit being frozen to see if an anti-browning treatment is suggested. Use ascorbic acid preparation as recommended in the chart or in the manufacturer's instructions.
- Use dry sugar, or sugar syrup in proportions suggested in the chart. Dissolve sugar needed in cold water. Stir. Allow to stand until sugar is completely dissolved. Do not heat. You may hold sugar syrup 2 days in the refrigerator. If you are preparing a sugarless pack of fruit that browns, be sure to treat with ascorbic acid or other anti-browning agents.
- Pack into plastic freezer bags, freezer containers, or freezer jars. Allow ½ inch headspace for expansion. Pack fruit, such as peaches, that tends to darken, in rigid containers and under the syrup by placing crumpled wax paper between lid and fruit.