 Cold Spray Drying: Birs Spray Tower
Burgdorf, close to Berne, the Swiss capital, is home to the unique cold spray tower, called the
Birs-tower. With its height of 75m it is the highest of its kind
in the worldwide
The concentrated pulp is sprayed free of any additives such as carriers
or anticaking agent (SiO2), from the top of the tower. From the bottom, dried and cooled (less than 50°C) air is blown into the tower. The resulting counter current is responsible for a
gently removing moisture from the pulp.
The thermal stress of the product is minimal, which is why an optimum retention of
color and taste as well as high protection of nutrients such as vitamins are guaranteed.
 Process parameter:
Inlet air temperature: maximum 50°C
Product temperature: maximum 40°C
Weekly capacity: 40 - 60 tons
Advantages of cold spray drying:
* Free flowing and pure products (no additives)
* High color and taste retention through gentle drying conditions
* Cost effective thanks to high capacity
* Dried products of high water binding capacity
Disadvantages of cold spray drying:
* Time consuming cleaning procedure
* High production capacity needed for an optimum rent abilityGo
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 Vacuum drying:
Due to low temperature operation, vacuum drying is a very gentle process which guarantees that the nutritional quality,
flavor and appearance of the final product is not affected. Vacuum drying is preferably used for temperature and oxidation sensitive products. Through the generated vacuum the boiling temperature of water present in the product is reduced. Depending on the product, a more porous texture is obtained. By using sieves of different mesh size, the finished product can be offered in different granulations.
 Process
parameters:
Heating: hot water of 70 - 80°C
Product temperature: max. 60°C
Vacuum: approximately 10mbar
Weekly capacity: approximately 6000 kg
Advantages of vacuum drying:
* Gentle drying conditions result in high product quality
* Closed system guarantees a high product safety
* Thanks to the porous texture, the final products show very good instant characteristics
* Drying to a very low final moisture content
* Possibility of drying liquid and/or sliced/whole products
* Drying without or with very low amount of added carriers is possible
Disadvantages of vacuum drying:
* High investment costs
* The products tend to show an increased hygroscopic and thermo plasticity.
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 Baby
food:
For many decades, SPREDA has been an innovative and reliable ingredient supplier for the
baby food industry. The name SPREDA stands for outstanding quality and highest product safety and has an excellent reputation through the most established world wide
baby food manufacturers.
Baby food is generally characterized by its pure and natural ingredients. The requirements in terms of pesticide residues are thereby particularly strict. Compared with foods for conventional use, the tolerable amount of every single pesticide residue lies at 10 ppb (0.01 mg/kg or 1 g/100 t), which is in line with the limit of detection for many pesticide compounds.
However, not exceeding the tolerable amount of pesticide residues is not always simple, since the ingredients and therefore the pesticide residues are concentrated up to 9 fold higher during the drying process.
Given that the technically possible detection limit for most of the pesticide residues lies at 10 ppb, it is not sufficient to analyze only the raw material as the limits could be exceeded by a multiple after drying. To avoid this, raw materials have to be selected very carefully and a sample of every batch has to be dried to analyze its pesticide residues.
Through its involvement in the baby food industry, a close collaboration with its farmers to ensure a strong compliance with the
baby food requirements. This takes place either through direct or indirect contract farming. As a result of the spray plans, as part of the documentation and the results of the sample analyzes, we will optimize and adjust the spray plans for the following year accordingly.
This perpetual cycle allows a constant adaptation and improvement of quality and safety of our products.
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