A method of masking the off-taste of an artificial or natural sweetener, comprising the addition to the sweetener of at least one compound according to the formula Iin whichR1 is selected from H, C1-C4 alkyl and Ph:R2 is selected from H and Me:R3 is selected from H, C1-C4 alkyl and Ph:R4 is selected from H and C1-C4 alkyl:or R3, R4 together form a five, six or seven-membered aliphatic ring.
