high fructose corn syrup

[Carl Pike]

Does anyone know how high fructose corn syrup is made?  Is it from 
stalks? Is it simply extracted from corn, and it happens to be high 
in fructose naturally?  Is it processed in some way?  I thought it 
could involve use of invertase to break down sucrose, but then it 
would be high in glucose as well as fructose.  Or is fructose added 
to the extract?  Why is it so common in processed foods (as compared 
to plain ordinary corn syrup)?
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