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.