A method of masking off-tastes in a comestible composition, comprising the addition to a comestible composition base comprising high-intensity sweetener, of from 20-50 ppm of at least one of cellobiose and psicose. The use of one or both of the materials is effective particularly in masking the off-tastes encountered with the use of high-intensity sweeteners. In a particular embodiment, cellobiose and/or psicose may be used to block the off-tastes in reduced-sugar or no-sugar comestible products containing no high-intensity sweetener.