'More than we realize sight is a key part of what makes food delicious. Partly, this is a result of learned experience : in the orbitfrontal cortex, the sight of food becomes associated with its taste, odour and texture. But it goes beyond this. Colour, for example, can actually alter our response to an odour directly in the primary olfactory cortex-the part of the brain that processes smell information - thereby changing the way we perceive that odour.'
The Fat Duck