There is an interesting theory being bandied about that there is a reason our sense of taste is associated with sweet, sour, salty, bitter and savory. This is because several different forms of these things may be essential to good health.
Important sugars include glucose, fructose, galactose, sucrose, maltose and lactose.
Important salts include the balanced electrolytes in our blood.
From there, sour and bitter, while seemingly unpleasant, are often indicators of all sorts of essential chemicals, as well as poisons.
Savory is an indicator of glutamate, which is an important neurotransmitter.
And of protein as well.