Frequently Asked Questions

The optimized refrigeration system delivers excellent energy performance while maintaining the required low-temperature water-vapor capture capability. Processing BRACE microspheres can further shorten the drying cycle and reduce energy consumption per unit of product.

Approximate energy consumption per kilogram of water removed: 2.5 kW·h/kg.

Microspheres are unlikely to break when suitable freeze-drying parameters are used. The particles are individually formed spheres and are thoroughly pre-frozen. Appropriate control of the temperature ramp and vacuum profile can effectively prevent them from sticking together.

The freeze-drying process allows control of both heating and cooling rates.

The shelves provide uniform temperature control with low temperature variation across each shelf. This ensures consistent heating of the material in the trays, reduces differences in microsphere dryness between locations and supports batch consistency.

Measurements recorded at multiple locations on different shelves show an overall temperature variation within 2 °C.

TOFFON freeze dryers provide stable low-temperature control of the ice condenser. The refrigeration system can be selected to suit the material and process requirements, providing the low temperatures and water-vapor capture capacity required for microsphere freeze-drying.

Single-stage refrigeration system: ice-condenser temperature of −35 to −50 °C.

Two-stage refrigeration system: ice-condenser temperature of −50 to −65 °C.

Cascade refrigeration system: ice-condenser temperature of −60 to −80 °C.

For liquid coffee concentrate loaded directly onto trays, the usual recommendation is 10–15 kg/m², with a liquid layer thickness of 10–15 mm. For solid microspheres produced using the BRACE process, voids remain between the particles. The loading capacity can reach 10–15 kg/m² and, under suitable conditions, up to 20–30 kg/m². A higher bed load is also possible.

The vibrating nozzle technology combines surface tension with fixed-frequency vibration to produce uniform droplet breakup (“Laminar Flow Rayleigh Breakup with Vibrating Nozzles”).

When a liquid is extruded in a laminar flow from an orifice, the surface tension forms a wave in the surface of the resulting liquid cylinder. The cylinder breaks up into similar sized droplets.

As in the natural – vibration free – break up the droplet size is not optimal, a larger variation including very small droplets (“Satellites”) are formed.

By vibrating the liquid directly (or indirectly via the nozzle/nozzle plate) in resonance to the wave on the surface, a very narrow size distribution of droplets are formed, the satellites vanish. The viscosity supports the forming of a droplet in the process and to stabilize the shape of the droplet.

Due to the technical setup, the vibration and flow is at any position of a high precision nozzle plate identical, even if the plate contains millions of nozzles. Therefore the droplet creation is identical over the nozzle place, creating only a very narrow size distribution of particles.

The need for a specific solidification system depends on the material to be processed. If the material are thermogelling typically a Fusion process with a cooling tower offers the best processing. In case of hydrocolloids like Alginate, Pectin, Agar or Gelatine, polymers or sol-gel processing, usually a Binder process setup is the better choice. In the Binder process direct contact thermogelling is also used.

Ionic crosslinking for materials as Alginate, Sols or some polymers are typically performed in a Binder process, UV curing of polymers in a Fusion type setup.

It depends on the material and application, which solidification system offers the best performance.

The droplet size area is selected by the nozzle diameter. With the process parameters the droplet size is fine tuned. As in the process first of all a droplet is generated, that is about 2 times the diameter of the nozzle, the final product diameter might vary if the collected and solidified particles are dried and then shrink. Typical shrink rates on drying are about 20-50%. For ceramics, sintering can produce further shrinking of ca. 20-30%.

For practical terms that means that to produce a 1 mm droplet, a 500 µm nozzle is used. With the same nozzle droplets of 800µm and 1200µm are usually feasible. Depending on the properties of the materials this range might be bigger or smaller.

Such a 1mm droplet can shrink on drying to e.g. 700µm. In case of a ceramic, it may finally have a size of 500µm after sintering.

BRACE equipment and processes can be configured with various options for use in the field of food/feed, cosmetic and pharma. This includes WIP (Wash-In-Place), CIP (Clean-In-Place) and SIP (Sterilize-In-Place) capabilities, closed systems, even pressurized isolated units.

Equipment: Machine parts in contact with the product are typically made from stainless steel (AISI 316) and a typical surface roughness of Ra<1.2, Ra<0.8 or even Ra<0.6 are available, depending on the application and scope. Other materials used in contact with the product are usually Glass or Plastic suitable for Food applications. Sealmaterial is usually FDA certified, unless technical reasons need something else (e.g. silver or carbon seals). Close systems, WIP, CIP, SIP can be configured, even over or underpressure isolation or glove boxes can be offered.
Processing environment: For desktop of laboratory units the operation in a suitable proper or cleanroom is recommended, especially for GMP purposes. For pilot and production units, full housing, glove boxes or mobile cleanrooms can be offered. Production units can be offered as closed systems and also with housing for over- or underpressure to prevent contamination of the material or the environement.
Feed pretreatment: As many raw materials for encapsulation are only available in food grade, BRACE offers inline sterilization for the raw materials, but also post production pasteurisation for food products as bubble tea.
Closed feed design: Production units can be offered as closed line systems to reduce contact with ambient air. Air showers, UV desinfection system or even fully isolated operation can be realized to remove the risk of contamination.
Process monitoring: Although monitoring does to avoid contamination, production units and as option smaller units offer sampling ports to confirm the quality and free-of-contamination for the material at checkpoints.
The hygienic level depends on the size and configuration of the unit. All units can be optionally designed for highest hygienic level, depending on the application and customer needs. For laboratory equipment and use e.g. in the probiotic nutrient field, desinfection and controlled rooms are often sufficient to product products.

The definition varies depending on the industry and the form of liquid. While in suspensions “solid content” typically referrs to the weight% of the insoluble material, it can also mean the amount of materials (in weight%) except the solvent (usually water).

In instant applications, this referrs to the residue when all water is removed, often also gives as BRIX.

In solution “concentration” includes only the material dissolved in the solvent and not the solid or liquid part. Here a “concentration” can differ from the “solid content”, if a liquid is both, a solution and a supsension at the same time, but also Emulsions can have both.