|MadSci Network: Neuroscience|
I'm not a chemist, but I am a neuroscientist and what you're talking about is sensory perception. The perception arises from chemical reaction, but not necessarily reactions between the different food chemicals.
You've probably heard the term "taste buds" before -- sensors on the tongue that specifically react to salty, sweet, bitter or sour flavors.
A good review for the general public is provided by the Society for
There's also a summary on Wikipedia that lists the many tongue sensations
You'll note these articles imply that there are a lot of unanswered questions about exactly how taste works. Your question gets at the basic issue of how different tastes combine.
The Wikipedia reference, under "savouriness", indicates that adding salt emphasizes the taste of tomatoes -- which suggests that the taste of the salt itself is obscured.
So I have to answer your question with another question. Are the combinations of tastes you noticed due to
(a) interaction between different taste sensors at the neuronal level
(b) combined action of two or more chemicals on a single sensor
(c) direct chemical interactions between two or more food chemicals
or (d) some combination of (a), (b) and (c)?
I couldn't tell you myself. On the other hand, I'm doubtful whether neuroscientists specializing in taste could tell you, either.
Try the links in the MadSci Library for more information on Neuroscience.