Flavour perception is a dynamic process, which must involve the consumer as
well as the chemistry and physics of the food, and must be matched by dyna
mic research methods. In time-intensity measurement a sensory characteristi
c is tracked as it changes over a period of time. Availability of volatiles
depends not only on their being present in the food, but also on their bei
ng released from the food and transferred to the olfactory receptors. Simul
ated mouths and chewing machines have provided useful data to aid understan
ding of what happens when food is tasted, and systems have been devised to
allow sampling of the headspace from the nose or mouth. Understanding of th
e interactions of flavour compounds with each other and with other componen
ts of the food, and of the fundamental physics of mass transfer, has provid
ed a limited ability to predict the behaviour of flavour compounds in some
food systems. (C) 2000 Elsevier Science Ltd. All rights reserved.