High-Fructose Corn Syrup

High-fructose corn syrup is a sweetener made from corn through industrial enzyme processing; the United States Food and Drug Administration has said it is not aware of evidence that it is less safe than traditional sweeteners such as sucrose and honey. Production starts by milling corn to extract starch, which is broken down by an acid-enzyme method, first with alpha-amylase cutting long starch chains into shorter sugar chains, then glucoamylase converting these to glucose; the solution is purified with activated carbon and ion-exchange resins, then passed over immobilized xylose isomerase to convert some glucose into fructose. The finished syrup is about 24 percent water, with the remainder mostly fructose and glucose plus up to 5 percent unprocessed glucose oligomers, sold chiefly as HFCS 42, with 42 percent fructose by dry weight, and HFCS 55, with 55 percent fructose, for different uses. The enabling enzyme was discovered in Japan in 1965, commercial production began in 1964, the syrup reached the market in the early 1970s, and the FDA classified it as generally recognized as safe in 1983, a finding it reaffirmed in 1996.