Should raw materials be graded?
I need it. Strawberries, blueberries, raspberries, mulberries and other types of berries have significant differences in maturity, and overripe fruits are prone to collapse, juice leakage, and mold growth; Immature fruits have poor flavor and a hard mouthfeel.
Before entering the line, it is recommended to remove damaged fruits, moldy fruits, and insect bitten fruits, and classify them according to size and maturity. Berries should not be soaked and cleaned for a long time. It is best to wash them gently with running water and drain or air dry the surface water as soon as possible after washing.
Can I directly enter the drying room after cleaning?
Not recommended. Too much free water on the surface can prolong the drying time, increase energy consumption, and easily cause the fruit surface to darken, adhere, and mold locally.
The production line can be equipped with draining, air drying, or room temperature drying sections to remove large water droplets on the surface before entering the drying room.
3. Whole fruit or split fruit?
Look at the variety and target product:
Strawberries: Large fruits can be cut in half or sliced, while small fruits can be whole; Dry more evenly after cutting.
Blueberries: can be whole or cut in half; More attention should be paid to the surface treatment and moisture removal of the whole fruit.
Raspberry and Mulberry: The fruit body is softer, and the whole fruit should be spread thinly to avoid collapse.
To make fruit powder or raw material powder: consider freeze-drying, microwave vacuum or slurry drying first, and then crushing.
Can the drying temperature be raised as soon as it comes up?
No. Berries have strong heat sensitivity and are prone to external dryness and internal moisture, blackening of color, and loss of aroma when dried quickly at high temperatures.
A more reliable method is gradient low-temperature drying, with mild dehydration in the early stage, enhanced dehumidification in the middle stage, and low-temperature setting in the later stage.
Reference idea:
Initial stage: 40-50 ℃, allowing surface water and some free water to slowly remove;
Mid term: 50-65 ℃, with strong dehumidification to accelerate internal moisture migration;
Post production: 40-50 ℃, softening, uniform water, and anti coking edge.
If the product emphasizes anthocyanins, vitamins, or original fragrances, the temperature should be kept low for a long time, avoiding exceeding 60-70 ℃ for a long time.
Why is dehumidification more important than warming up?
Berries have high water content and sugar acidity, making it difficult for water vapor to escape from the drying room. Even at high temperatures, they cannot be fully dried and are prone to yellowing, softening, and mold growth.
Focus on:
Is the moisture outlet unobstructed;
Is the addition of fresh air reasonable;
Whether timely and strong dehumidification is carried out during the high humidity stage in the early and middle stages;
Whether the wind speed in the drying room is uniform and avoids dead corners.
Some processes may set up a "stop heat cycle" or "softening section" in the middle stage to allow the moisture inside the fruit to migrate outward, and then continue to remove moisture.
How to control the thickness and loading capacity of the paving material?
Try to lay it flat in a single or thin layer, avoiding stacking. Leave sufficient air ducts between the trays, and the mesh fabric should be evenly distributed.
Excessive loading can lead to insufficient penetration of hot air, resulting in a situation where the edges are dry and the center is still soft. The volume of different berries varies greatly, so it is best to determine the maximum loading thickness based on a single batch trial drying.
7. To what extent is it considered qualified to be baked?
You can't just look at the time, you need to look at the final water and feel:
Dried fruits are non stick to the hands and have a dry surface;
Open without obvious wet core;
The taste is flexible or crispy, depending on the product positioning;
Maintain the inherent characteristics of the variety in color, without obvious blackening or dullness;
The fruit aroma is normal, without any sour or moldy taste.
If stored for a long time, the final water usually needs to be reduced to a lower level; If making soft glutinous preserved fruits, slightly higher moisture content can be retained, but it must be combined with sugar soaking, packaging, and storage control.
Can it be packaged immediately after leaving the room?
No. The temperature of freshly dried berries is relatively high, and sealing them directly can easily cause condensation and moisture regain.
It should be cooled to near room temperature in a dry and clean environment before being graded and packaged. High barrier bags should be used for packaging materials, and if necessary, deoxidizers, desiccants, or nitrogen filled packaging should be used to avoid anthocyanin oxidation and mold growth.

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