A team of British process engineers has developed a technique for producing artificial casings from collagen that protects product quality and triples production. The process is based on precise monitoring of temperature and humidity with Vaisala sensors and multi-stage feedback control.
Advantages of collagen casings
The production of artificial casings from collagen derived from animal skin is an excellent example of sustainable production because a waste product is turned into a valuable raw material and helps to improve the quality and consistency of sausages.
However, all sausage casings are sensitive and require compliance with precisely defined conditions and careful handling during production, storage and distribution. This applies right through to the production of the sausages. Natural casings from the small intestine of slaughtered animals generally have different lengths, diameters and thicknesses. They are therefore not suitable for high-speed processes in sausage production, whereas artificial casings made from collagen have reliably consistent properties and are therefore ideal for fast and efficient processes. In addition, collagen artificial casings do not need to be cooled and have a longer shelf life than conventional casings. Collagen artificial casing is ready to use straight from the packaging, the hopper is quick and easy to load and there is no need to soak and untangle bundles.
There are no seasonal variations. In addition, sausages made with collagen casing can be cooked more evenly compared to sausages in natural casing. This also contributes to a better appearance when cooked.
Development of a new production process for collagen
Originally, the artificial casing manufacturer used a collagen dryer with a conveyor belt, but its frictional resistance caused cracks and produced rejects. The process was slow and uneconomical. The engineers therefore wanted to develop a new, less damaging technology for drying and processing the cylindrical artificial casings made of collagen produced by extrusion for sausage production.
Sausage casings have very specific physical characteristics and must have extremely consistent properties. The new process therefore had to minimize friction and at the same time ensure optimum temperature and moisture values. Too high or too low humidity can affect the quality of the end product.
To make the systems independent of the geographical location, they had to be able to react to the ambient conditions. The new solution enables the artificial casings to be inflated with hot, dehumidified process air from a blower based on silica as a desiccant. An innovative system has been developed to feed the inflated artificial casing. The new system uses three precision sensors. A Vaisala humidity sensor monitors the humidity of the environment. If the outside air is too humid, dry air is circulated. In addition, two Vaisala dew point sensors monitor the process air to ensure ideal conditions for the collagen products with a control system based on multi-level feedback.
The humidity sensor is based on Vaisala's HUMICAP® technology, a capacitive thin-film polymer humidity sensor that is accurate, reliable, stable over time and insensitive to condensation and contamination. The dew point transmitters contain Vaisala's DRYCAP® sensor , which has also been developed for accuracy, reliability and stability. The sensor is insensitive to condensation and immune to contamination. However, the unmatched performance of DRYCAP technology is based on the thin film capacitive polymer sensor and auto-calibration function. The sensor also offers fast response and rapid recovery of function after wetting.
Juhani Lehto, Product Manager at Vaisala, says: "This team uses Vaisala sensors regularly because the food processing equipment is supplied to customers around the world who operate in a wide range of environmental conditions. They therefore need sensors that are not only accurate and reliable over the long term, but also minimize maintenance."