Gelatine is the name for a group of proteins obtained from treatment of collagen. As raw materials for gelatine production are used, e.g. pig and beef skin, bones from slaughterhouses, skin and bones from poultry, and skin from fish. The extraction conditions can be acid or alkaline, it can take place at different temperatures and different lengths of time, and the resulting products can be very differ-ent in functionality. For obtaining some specialty low molecular products the gelatine is treated with enzymes.
The production process
During the production is used several unit operations among which are batch extraction or con-tinuous extraction in a CONTEX™ extractor. Acidity/alkalinity, temperature, extract ratio and time are controlled. The extracts are cleaned by mechanical separation filtration through self cleaning filters or sheet filters. The filtrate can be further purified from minerals by the membrane filtration and ion-exchange.
The obtained purified filtrate is approx. 5 % TS and is concentrated in a falling-film vacuum evaporator. This concentrate is finally filtered, pasteurized and solidified by cooling on belts or drums. Alternatively, the product can be spray dried.
Two types of gelatine products
In principle gelatine is available as two different types of products:
- The high molecular gelatine can be spray dried from a feed with low concentration forming a fluffy product, which afterwards can be milled into a powder.
- The specialty products of low-molecular gelatine can also be spray dried and from higher concentrations forming a free-flowing agglomerated product. This is done in a spray dryer with integrated fluid bed and fines return. These powders are soluble in cold water.