Coextrusion of a fresh preparation with a vegetable casing
A coextruded sausage with a vegetable casing has the aspect of a regular sausage. The skin is a fully edible veggie alternative. The process requires attention throughout the forming, coating and drying operations.
The core is made of a meat, fish, cheese, or vegetable-based compounds.
The coating is prepared with:
- A hydrocolloid such as alginate
- A calcium salt
Optionally, the coating film can be mixed or further coated with:
- A spice coating
- A smoke flavour
How does it work?
The coating occurs with the forming of a film and its setting by a reaction with calcium salt which polymerizes it.
The thickness and firmness of the alginate film results from the respective hydrocolloid and salt proportion in water.
It is a continuous operation. Speed is adjusted to balance firmness and softness for cutting and closing the edges. The coating sequences run as follows:
Forming of the core material into a mostly round, sausage-like, cohesive rope
Simultaneous coextrusion with a fluid alginate-based film
Combination or immersion into a solution of calcium salt
Draining of the coated rope optionally
Cutting into portion, partial drying
The operation occurs in a former for sausage which has been adapted with a coextrusion head or device to apply a film all around the core shape.
After coating, the product can be kept as such. It is usally partially dried to reduce the coating thickness and give it a crispy texture.
Machine design. Courtesy of Albert Handtmann GmbH
How do you measure your success?
Key quality features
The product is fresh and with versatile definition
No excessive bumps, cylindrical shape
No cracks and leaks
Solidity of the casing
Key quality parameters
Multiple factors to play with
Specific taste, texture and rheology
Alginate quality, use of inclusions
Residence time, constant calcium concentration of the reaction bath