- First, cornstarch is treated with alpha-amylase to produce shorter chains of sugars called polysaccharides. Alpha-amylase is industrially produced by a bacterium, usually Bacillus sp. It is purified and then shipped to HFCS manufacturers.
Next, an enzyme called glucoamylase breaks the sugar chains down even further to yield the simple sugar glucose. Unlike alpha-amylase, glucoamylase is produced by Aspergillus, a fungus, in a fermentation vat where one would likely see little balls of Aspergillus floating on the top.
The third enzyme, glucose-isomerase, is very expensive. It converts glucose to a mixture of about 42 percent fructose and 50-52 percent glucose with some other sugars mixed in. While alpha-amylase and glucoamylase are added directly to the slurry, pricey glucose-isomerase is packed into columns and the sugar mixture is then passed over it. Inexpensive alpha-amylase and glucoamylase are used only once, glucose-isomerase is reused until it loses most of its activity.
There are two more steps involved. First is a liquid chromatography step that takes the mixture to 90 percent fructose. Finally, this is back-blended with the original mixture to yield a final concentration of about 55 percent fructose--what the industry calls high fructose corn syrup.
HFCS has the exact same sweetness and taste as an equal amount of sucrose from cane or beet sugar but it is obviously much more complicated to make, involving vats of murky fermenting liquid, fungus and chemical tweaking, all of which take place in one of 16 chemical plants located in the Corn Belt. Yet in spite of all the special enzymes required, HFCS is actually cheaper than sugar. It is also very easy to transport--it's just piped into tanker trucks. This translates into lower costs and higher profits for food producers.
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