Dried Apple Production
1. Processing: A commercially available corer-peeler-slicer can process 25kg of fresh apples in 2 hours. This produces a spiral of apple in one action, which can then be separated into rings with one cut by a stainless steel knife. As soon as the rings have been cut, they are placed in a solution to prevent darkening
of the rings.
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Screw clamp is recommended.
Suitable pretreatment solutions are:
Concentration | Name | Formula |
2% (100g in 5L ) | Sodium Metabisulfite | Na2S2O5 |
3% (150g in 5L) | Ascorbic Acid | C6H8O6 |
1% (50g in 5L) | Salt | NaCl |
0.5% (25g in 5L) | Citric Acid (lemon juice) | C6H8O7 |
Chemicals Available from: | Geojemi, V. Pshavela 20, Tbilisi 99599172460 | Cost: 6lari / kg |
Sodium Metabisulfite is cheaper and more readily available. It is more suitable for longer term storage.
Rings can be produced without peeling and without pretreatment, but this will result is a darker product. As soon as the rings are cut, they are placed in the solution, and submerged for at least 10 minutes.
A plastic mesh is first placed over the dipping bowl, to enable the rings to be removed easily without losing the solution. Because the rings tend to float, a weighted dish is used to ensure that the rings remain fully submerged for 10 minutes. Once the pretreatment is completed, the rings are removed from the solution by the net, and rinsed in clean water.
The pretreatment solution can be used to treat 3 times its volume of apple rings. In Europe there is a market for unpeeled, and also untreated, apple rings. Unpeeled apple rings take longer to dry.
2. Drying method: The treated apple rings are then laid out in a single layer on drying frames. Ground cinnamon can be sprinkled in the apples to improve the taste. The frames are laid inside the dryer. At 60 degrees Celcius, the rings take about 4 hours to dry. The rings dry quicker towards the end of the drying time, so care must be taken to prevent overdrying. Once rings are dry, they can be removed from the drying tray. At this point, the moisture content of the apple rings should be 20%.
The test for dryness is that the ring feels warm to the touch. When cut in half, there is no sign of moisture. Also, no moisture can be squeezed from the pieces. A ring folded in half should not stick to itself.
The dried apple rings are collected from the trays. Any brown edges (from bruising during picking) can be cut off with scissors. The rings are graded. Mis-shaped, broken or part rings can be cut into small pieces to be sold as chopped apple.
3. Equilibration: Once cooled, the apple rings are placed in a clear plastic container. The sack is sealed. Over a period of 7-10days, the sack of rings is shaken by hand to ensure equal moisture distribution. If any moisture appears, any damp pieces should be removed for further drying.
4. Storage: The fully dried apple rings are then packed in cardboard cartons with a polythene liner for distribution and sale. The apples can also be packed into retail containers such ziplock poly bags. As much air as possible should be removed from the bag.
5. Hygiene: The next person to touch the apple rings after the bagging stage will be customer! Care must be taken to avoid the presence of hair, clothing threads or dirt in the apple rings. A clean dry work surface should be used, in a room free from insects. Any person preparing or processing the apple rings should wear short sleeves, a cap and plastic gloves. Hands should be clean.
6. Marketing
Dried apple rings can be eaten as a snack or chopped for use in home baking or cereals. To reconstitute the rings, they should be covered with boiling water, and soaked for up to 30 minutes. They can also be covered in water and simmered for 10 minutes.
Dried apple rings are a good source of carbohydrates, dietary fibre, and are very low in fat, with no cholesterol. They contain moderate amounts of copper, iron, Vitamin B6 and other minerals like calcium, phosphorus, zinc and manganese.
7. Peeler Setup and Cleaning
The peeler blade should be set to 3mm beyond the peeler arm.
The blade can be sharpened with a circular file.
The peeler-corer-slicer contains 3 sharp blades as shown.
The forks which hold the apple must pass cleanly through blade 2.
Care should be taken not to overtighten the holding clamp.
After use, the peeler-corer-slicer should be rinsed in water and dried. A drop of vegetable oil can be placed on moving parts.