[Translate to english:] Sprühtrocknung Lebensmittel

Contract Manufacturing - Spray Drying

Spray Drying of Foodstuffs

Drying is one of the oldest methods of conservation for foodstuffs. There are a variety of methods to preserve foodstuffs or their raw materials in this way. One of those is spray drying. Spray drying is gentle and extremely suitable for continually drying even large amounts.

The Production business unit of UFAG LABORATORIEN can offer you contract manufacturing of spray products in our own spray tower in Switzerland. Alongside the production of pharmaceutical active ingredients, drying of foodstuffs and of foodstuff extracts and plant extracts is also carried out. Contract spray drying at UFAG LABORATORIEN is characterised by the following points:

  • Manufacturing permits for pharmaceutical active ingredients - GMP certificate
  • Certification for the “kosher” dietary rules
  • Depending on the product, bio certification is possible
  • Incoming goods checks: Testing of the supplied raw materials and storage of reserve samples is available on request: Analysis of the raw materials in accordance with your specifications
  • In-process checks: e.g. for residual moisture, bulk density and size analysis
  • End inspections / Approval: Analytical testing of the finished product according to your specifications and including microbiology with no loss of time
  • Detailed documentation of the manufacturing process allows batch-exact traceability of the products

The facility fulfils the GMP regulations completely. Operations have been authorised by the Swiss authorities and are regularly examined by Swissmedic.

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Your contact person
Contract manufacturing / spray drying

Michael Güthlin

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Production capacity

The performance range of the facility is approximately 400kg of water evaporation per hour. Production capacity amounts to between 150 and 400 kg/h, depending on the properties of the product to be processed.

Flexibility and the wishes of the customer are a priority for us. So, production series of less than 100kg up to many tonnes can be handled without any problems.

Drying tower
Drying tower

Pre-treatment of the product

Necessary pre-treatment of the product, such as pasteurisation, or the addition of additives can be carried out before the spray drying process.

A dosing device is available for the adding of flow additives such as silicon dioxide during the spray drying process.

Food conservation by drying

Humans have, over the course of the centuries, developed a number of methods to keep foodstuffs edible and to be able to store them. One of these methods is conservation by dehydration, so-called drying. The industrial drying of foodstuffs began at the end of the 19th century and is still used nowadays in a number of different areas. In this way, the foodstuffs are not just dried as a whole, its associated aromas and extracts are also dried.

There are a number of methods for the drying of foodstuffs, which have different effects on the contents and quality of the product. It is not only temperature that plays a large role thereby, but also the length of time that the foodstuff is exposed to the heat. One of these processes which is in use from the laboratory scale right up to large-scale commercial production, is spray drying.

The principle of spray drying

Spray drying effectively uses the principle of surface area enlargement. The spray dryer belongs to the class of convective dryers, in which the energy for the evaporation of the solvent (which is often water) is transferred from the drying gas to the material that is to be dried by thermal conduction. Spray drying is a sequence of four processes and takes place in a matter of seconds.

Step 1: Atomisation

Liquid products are atomised into fine droplets at the upper end of the dryer with the help of an aggregate. Here, there are two fundamentally different types of atomisation:
a) Rotation or centrifugal force atomisation
b) Nozzle atomisation

In rotation or centrifugal force atomisation, the material to be dried is finely atomised using a rotating disc travelling in the direction of the hot air stream. Due to the approximately horizontal direction of the atomised droplets, rotating spray dryers require a tower with a relatively large diameter.
In nozzle atomisation, the raw material is sprayed into the hot air stream using a nozzle, either in the direction of the hot air stream (same current) or in the opposite direction (opposite current)

Step 2: Contact/mixing of the spray solution with the drying medium (hot air)

The finely sprayed fluid particles come into contact with the hot air. As soon as the droplets have formed, they must be mixed with a sufficient amount of warm drying gas. Mixing of the atomizers occurs as a result of the high speed of the droplets upon entry into the dryer.

Step 3: Drying

95% of the water in the droplets evaporates within seconds. The round droplets that arise from the atomisation are dried very quickly as a result of their large surface areas and hence their large areas of contact with the hot gas stream. Even with the air supplied at a very high temperature, the evaporation cooling keeps the temperature of the good low and that guarantees gentle drying.

Ideally, the spraying property leaves the dryer at exactly the moment in which all of the water has evaporated. Hereby, the resulting particles differ in terms of shape, size, particle size distribution and stability according to the process parameters that were set and the source material that was used.

Step 4: Separation

The main quantity of the particles in the spray dryer fall downwards as a result of gravity and are led away into the transportation air duct. The main amount of air will be lead into the downstream Cyclone. Because of this, the flow velocity will decelerate and eventually, particles that were carried along will be separated and led into the transportation air duct. Afterwards, the product will be filled into the containers.

A schematic representation of the spray drying process
A schematic representation of the spray drying process

Advantages of spray drying

The advantages of spray drying are:

  • Drying and shaping of the particle in one step
  • Gentle drying of temperature sensitive products
  • Large product throughput
  • Continual process

Powder quality and aids

Foodstuffs and special plant extracts are mostly natural products. Their ingredients are subject to fluctuations As a result, in the case of spray drying, it is not possible to always use the same parameters, such as input and output temperatures. Due to the variability, comprehensive technical expertise is necessary to receive the desired quality of powder.

Ingredients and substrates can both sometimes mean that a foodstuff can only be dried into the form of easy flow powder with great difficulty, using the spray drying process. This can mean that it is essential to add auxiliary materials such as fumed silica.

The fumed silica will be added during the drying process. The silica refines the free-flowing properties of a variety of different powders. The auxiliary material will be added directly into the product stream in dosed amounts to achieve the optimum results.

Filling and packaging

Containers that are to be filled can be selected by the customer, such as bags, cartons, Bag in Box or Big Bags. Depending on the product, amounts to be filled from anywhere between 5 and 1,000 kg per container are possible.

Spray drying: Container sealing
Spray drying: Container sealing

Quality control

Alongside spray production, UFAG LABORATORIEN also offers a wide range of analytical methods for pharmaceuticalsfoodstuffs and agroecology. The company is accredited in accordance with ISO 17025, GMP certified and FDA approved.

Our services in detail:

  • Consultation on spray drying:
  • Acceptance of solutions in volumes from 500 up to 40,000 litres (tanker truck) is possible
  • Pre-treatment of spray solutions (pasteurisation, substrates)
  • Homogenisation
  • Addition of flow additives during the spraying process (silicon dioxide)
  • Spray drying
  • Filling and packaging
  • Quality control of foodstuffs
  • Additional services are according to the directory of services or upon request.
Spray drying: Cyclone
Spray drying: Cyclone