Starch to syrup conversion
To convert starch to syrup, the starch, suspended in water, is liquefied in the presence of an enzyme to convert it into a low-dextrose solution. Another enzyme is added to continue the conversion process. At any time the enzyme treatment can be halted to produce the right mixture of sugars (like dextrose or maltose) for syrups to meet different needs. In some syrups, the conversion of starch to sugars is halted at an early stage to produce low-to-medium sweetness syrups. In others, the process is allowed to proceed until the syrup is nearly all dextrose. The syrup is refined in filters, centrifuges and ion-exchange columns, and excess water is evaporated. The syrups produced are sold directly, crystallised into pure dextrose, or processed further to create high fructose corn syrup or crystalline fructose.
The corn is coarsely milled in the cracking mills to separate the germ from the rest of the components (including starch, fibre and gluten). Now in a form of slurry, the corn flows to the germ or ‘cyclone’ separators to separate out the corn germ.
The corn germ, which contains about 85% of the corn’s oil, is removed from the slurry and washed. It is then dried and sold for further processing to recover the oil.
The remaining slurry then leaves the separation step for fine grinding. After the fine grinding, which releases the starch and gluten from the fibre, the slurry flows over fixed concave screens which catch the fibre but allow the starch and gluten to pass through. The starch-gluten suspension is sent to the starch separators.
The collected fibre is dried for use in animal feed.