Until recently, there was no consensus about whether umami
was a true taste quality at all, much less that it could be
categorized together with sweet as we do here. The concept of
umami, which perhaps translates best into English as ‘savory’ or
‘meaty,’ was suggested by Japanese investigators as a unique
quality exemplified by monosodium glutamate (MSG), but with
an unusual property of synergy: when MSG is combined with a
ribonucleotide, such as inosine monophosphate, the perceived
intensity of the mixture is increased above the intensity of either
compound alone. Ribonucleotides are a family of compounds
often found in meat. Umami was confirmed as a basic taste
quality when the umami receptor was discovered (described
below). Because part of the umami receptor is shared with a part
of the sweet receptor, we discuss these two taste qualities
together here.