High maltose corn syrup is a food additive used as a sweetener and preservative. The majority sugar is maltose. It is less sweet than high fructose corn syrup, and contains little to no fructose.It is sweet enough to be useful as a sweetener in commercial food production, however.To be given the label "high," the syrup must contain at least 50% maltose.Typically, it contains 40–50% maltose, though some have as high as 70%.

By using β-amylase or fungal α-amylase, glucose syrups containing over 50% maltose, or even over 70% maltose (extra-high-maltose syrup) can be produced.This is possible because these enzymes remove two glucose units, i.e., one maltose molecule at a time from the end of the starch molecule.