[lō¦brē·də¦brīn ′ā·kən‚shtīn ‚trans·fər‚mā·shən] (organic chemistry) The change in which an aldose sugar treated with dilute alkali results in a mixture of an epimeric pair and 2-keto-hexose due to the production of enolic forms in the presence of hydroxyl ions, followed by a rearrangement.