Enzyme Technology
Use of immobilised raffinase
The development of a raffinase (a-D-galactosidase) suitable for commercial use is another triumph of enzyme
technology. Plainly, it would be totally unacceptable to use an enzyme
preparation containing invertase to remove this material during sucrose
production (see Chapter 4). It has been necessary to find an organism capable of
producing an a-galactosidase but not an invertase. A mould,
Mortierella vinacea
var. raffinoseutilizer, fills the requirements. This is grown in a particulate
form and the particles harvested, dried and used directly as the
immobilised-enzyme preparation. It is stirred with the sugar beet juice in batch
stirred tank reactors. When the removal of raffinose is complete, stirring is
stopped and the juice pumped off the settled bed of enzyme. Enzyme, lost by
physical attrition, is replaced by new enzyme added with the next batch of
juice. The galactose released is destroyed in the alkaline conditions of the
first stages of juice purification and does not cause any further problems while
the sucrose is recovered. This process results in a 3% increase in productivity
and a significant reduction in the costs of the disposal of waste molasses.
Immobilised raffinase may also be used to
remove the raffinose and stachyose from soybean milk. These sugars are
responsible for the flatulence that may be caused when soybean milk is used as a
milk substitute in special diets.
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This page was established in 2004 and last updated by Martin
Chaplin on
6 August, 2014
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