In the refinery a starch suspension is heated by steam injection to gelatinise at temperatures above 95°C to form a low solids content liquor.
This liquor is hydrolysed in a two-step conversion process of either acid, acid/enzyme or enzyme/enzyme treatment.
Throughout the process, refiners can halt acid or enzyme actions at key points to produce the right mixture of sugars like glucose and maltose for syrups to meet different needs.
After pH adjustment and enzyme inactivation the liquefact is passed through filters for clarification, is evaporated to an intermediate concentration, run over ion exchange columns and finished off by carbon treatment or polisher resins thus removing colour and odours and improving stability.
The intermediate syrup is finally evaporated under vacuum to raise the solids content to some 77-85%.