The key to drying kiwifruit lies in preventing oxidation and browning, slice thickness, segmented temperature control, moisture removal, moisture content, softening, and moisture-proof packaging. It is more prone to discoloration and stickiness than apples and apricots, so the pre-treatment and temperature control should be finer.
1. Don't choose raw materials that are too ripe
It is recommended to choose kiwifruit that is eight to nine mature, with hard flesh, free from pests and diseases, and free from mold and rot.
Over ripe fruit slices are prone to collapse and softening, and become sticky and moldy after drying; Too raw fruit acid is astringent and lacks flavor.
2. After peeling, it is necessary to immediately prevent oxidation
Kiwi fruit is prone to browning after cutting, and color protection should be done immediately before and after slicing.
Common methods:
Short term soaking in diluted salt water or citric acid/vitamin C solution, suitable for small-scale and additive free processes;
Blanching: Hot water or boiling water at 85-90 ℃ for 2-3 minutes can kill enzymes and stabilize colors, then quickly cool and drain;
Traditional techniques may use alkaline solution for peeling, sulfur fumigation, or sodium metabisulfite for color protection, but commercial production must strictly follow local food additive standards, and it is not recommended to use sulfur fumigation on one's own. one
3. The slice thickness should be controlled between 4-6mm
Generally recommended is 4-6mm, too thin can easily burn or break; If it is too thick, the outside will be dry and the inside will be wet, and the drying time will be significantly prolonged.
Slices should be evenly distributed and placed in a single layer without overlapping, otherwise there will be significant differences in dryness within the same batch.
4. The drying temperature should be segmented and should not be too high from the beginning
Kiwi fruit has high sugar content and soft flesh. In the early stage of high temperature, it is easy for the surface to crust, and the internal water cannot be extracted.
Process direction reference temperature description
Process direction reference temperature description
Hot air/heat pump drying with 50-60 ℃ segmented low-temperature dehumidification in the early stage, followed by drying at 55-58 ℃ in the later stage
Traditional industrial drying at 65-75 ℃ takes about 20-24 hours, and it is necessary to prevent external coke and internal moisture from reaching 15 degrees Celsius
Home dryer/oven at 55-60 ℃ for about 8-12 hours, flipping 1-2 times in the middle
Heat pump drying is more suitable for kiwi drying because it can simultaneously control temperature and humidity, and better preserve color, aroma, and taste.
5. Moisture removal is more important than simply heating up
Kiwi fruit has a high sugar content. If the humidity in the drying room cannot be released, it is prone to "stuffiness": the surface becomes sticky, the color becomes dark, and it dries slowly.
In the middle and later stages of drying, continuous dehumidification is required. In the early stage, a slightly higher temperature can be used to help with moisture migration, and in the later stage, it can be lowered to 50-58 ℃ and slowly dried to set the color.
6. Control the moisture content between 15% and 20%
Qualified dried kiwifruit typically manifests as:
The surface is dry and non stick to the hands;
The flesh is flexible and not easily broken when bent;
After being opened, there is no obvious wet core;
After cooling, there will be no rapid return of moisture and water.
The moisture content of the finished product is generally controlled at around 15% -20%; If you want to make dried fruits that are more durable for storage, it is advisable to keep them close to 15% or less.
7. Softening and soaking cannot be saved
Freshly dried kiwifruit often has a drier outer layer and a slightly wetter inner layer. It can be sealed and left to stand for 12 hours to 1 day to allow moisture to redistribute, resulting in a more flexible taste.
If moisture, stickiness, or odor is found inside the bag during the softening process, it needs to be reheated.
8. The packaging should be moisture-proof and moisture resistant
Dried kiwifruit should be packaged as soon as possible after cooling. It is recommended to use aluminum foil bags, vacuum bags, or nitrogen filled packaging, and food grade desiccants can be added.
The storage environment should be cool, dry, and away from light. During the rainy season in Shanghai and Jiangnan, the humidity is high. It is recommended to store in a dry environment after refrigeration or sealing to avoid moisture regain, stickiness, and mold growth.

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