Protein extract (meat, fish, poultry) concentration

The food industry is experiencing major growth in the production of meat-based ingredients for addition to final food products. Companies around the world are using Flavourtech’s Centritherm® evaporator to produce high quality stock concentrates and powders manufactured from a variety of sources with, or without, the addition of vegetables.

Examples include:

• Meat stocks from beef and pork using bones and meat by-products
• Fish concentrates from bonito and tuna flesh and off-cuts
• Poultry stock from chicken and turkey meat, carcasses and bones
• Microbiological broths

Companies producing such products are not only taking advantage of the Centritherm evaporator to meet both customer and logistical requirements, but also using Flavourtech’ Extraction and Spinning Cone Column Aroma Recovery technologies.

Key benefits of the Centritherm include:

• Exceptionally short product residence times (1 second!)
• Low operating temperatures (around 50°C)
• Preservation of flavour and colour
• No reduction of protein functionality
• Low hold-up volume (losses of only a few litres in the largest model)
• Reduced fines by the spray dryer
• Increased dryer capacity
• Lower overall energy requirements

Negligible thermal impact

Traditional multiple-effect evaporators, on the other hand, are not as effective in concentrating protein extracts. Use of this technology is usually accompanied by a reduction in protein functionality, damage to colour and flavour and processing difficulties, such as fouling of the heated surface.

Due to the heat sensitive nature of protein extracts, the standard Centritherm evaporator operating conditions (50°C evaporation temperature & 120°C steam temperature) may also be adjusted to reduce the difference between evaporation and steam temperatures. For example, an evaporation temperature of 40°C and a steam temperature of 90°C, are not uncommon when processing protein extracts.

High Viscosity Processing
Even at relatively low concentrations, protein extracts can be quite viscous, making complete coverage of the heated surface difficult. In conventional evaporators, this is overcome by maintaining high flow rates, which in turn require a high rate of product recirculation to achieve the target concentration and maintain an acceptable flow rate. As a result, traditional evaporators have longer residence times giving rise to thermal degradation of proteins.

The Centritherm evaporator uses centrifugal force to ensure that the protein solution is evenly distributed across the heating surface. In fact, the thickness of the product film inside the Centritherm can be reduced to just 0.1 mm before the risk of discontinuity becomes significant. This centrifugal force also allows higher concentrations to be achieved as, unlike traditional evaporators, viscosity does not become a limitation.

Increased Dryer Capacity
Protein extracts are often concentrated using membrane filtration techniques, such as ultrafiltration. Membrane filtration, however, has limitations in achieving high concentrations thereby creating restrictions on downstream dryer capacities. The Centritherm evaporator, on the other hand, allows higher concentrations to be achieved, thus increasing dryer capacity.

The throughput of a spray dryer with a fixed drying rate may be substantially increased by implementing a Centritherm evaporator to further concentrate the extract prior to spray drying. The maximum solids concentration achieved by ultrafiltration is normally less than 30% total solids. The retentate is then fed to a spray dryer. Alternatively, a Centritherm evaporator may be used to increase the concentration of the spray dryer feed. For some products, such as meat broths, this may be as high as 70% total solids.

In addition to increased dryer throughputs, other process benefits are achieved by feeding a more highly concentrated material to the spray dryer. This includes increased bulk powder density (and hence better packing) and a reduced production of fines.

Fabrication to Food Standards
Special consideration is provided to ensure hygienic design and Clean-In-Place (CIP) capabilities for the Centritherm evaporator. Moreover, specific design requests, to meet end user’s internal standards, can also be taken into account.

Centritherm evaporators have been installed for the production of high quality beef, fish and poultry protein concentrates around the world. A range of models are available for both batch and continuous processing.

Click here to find out more about the Centritherm® evaporator .