Enzymes are used merely as aids in the sugar industry (sucrose from sugar cane or beet). They remove contaminant materials which make the processing difficult:
· The presence of significant amounts of starch results in high viscosities during downstream processing, as the naturally occuring a-amylases (which hydrolyze starch into soluble dextrins) are inactivated by the heat treatment in sugar production. This treatment is carried out to destroy cane juice invertase (which hydrolyzes sucrose into glucose and fructose) so that no sucrose yield is lost by inversion.
This problem can be overcome by addition of highly thermostable a-amylases which are able to perform their task under those conditions.
· The sucrose crystal growth is inhibited if dextran and raffinose are formed in the raw materials.
If necessary raffinose is hydrolysed to galactose and sucrose by a fungal raffinase.
Dextran is a glucose polymer which exhibits a high viscosity in solution. This problem is frequently solved by the use of fungal dextranases.
These are, however, only exceptionally used because: