Final Ideas: Taste Manipulator

The basic tastes are the commonly recognized types of taste sensed by humans. Humans receive tastes through taste buds, concentrated on the upper surface of the tongue. Scientists describe five basic tastes: bitter, salty, sour, sweet, and savoury.
There is scientific dispute as to whether basic tastes exist, or are simply an "overly reductionist" concept. There is also philosophical dispute between biochemists, who believe evidence for a chemical reaction in tongue tissue means there is a basic taste, and psychologists, who see taste as much more based on psychological states and experiences.

There are 2 ways that humans can taste flavours - through the nose and through the tongue.
The receptors in the nose are around 10,000 times more sensitive than those in the mouth, which is why when you have a "blocked nose", you lose almost all sense of taste.

A common misconception is that certain areas of the tongue are responsible for different types of taste. On the contrary, all taste buds can detect all 5 types of taste, but some are more responsive to different types than others.

The 5 types of taste are as follows:
--Saltiness
Saltiness is a taste produced by the presence of sodium chloride, and can pass directly through ion channels in the tongue, leading to a wave of electrical discharge that travels along the membrane of a cell. Action potentials are an essential feature of animal life, rapidly carrying information within and between tissues.

--Sourness
Sourness is the taste that detects acids. The mechanism for detecting sour taste is similar to that which detects salt taste.

--Sweetness
Sweetness is produced by the presence of sugars, some proteins and a few other substances. Sweetness is detected by a variety of G protein coupled receptors coupled to the G protein gustducin found on the taste buds. At least two different variants of the "sweetness receptors" need to be activated for the brain to register sweetness.

--Bitterness
Research has shown that TAS2Rs (taste receptors, type 2) coupled to the G protein gustducin are responsible for the human ability to taste bitter substances.

--Savouriness
A subset of savoury taste buds responds specifically to glutamate in the same way that sweet ones respond to sugar. Glutamate binds to a variant of G protein coupled glutamate receptors.

From these descriptions, you can see that the basic ways in which the taste is detected, is a chemical reaction causing electrical impulses to be sent to the brain.

Taste from smell works in a similar way - electrical impulses are sent directly to the brain via nerves directly connected to the emotional centre of the brain. This is explains why sometimes childhood and other important memories can be triggered from scents or flavours.

In terms of a device that could be used to "alter" the taste of foods, it could be fitted into either the nose or the tongue, as both have a say in what you taste, however, if it were to be used with the receptors in the nose, it would be more effective in terms of overriding the existing taste of the food.

A tiny device that could be clipped to the nose at meal times and could be recharged between usage would be ideal for this application, and this could be used as a training device to "trick" a childs brain into liking a type of food that they previously wouldn't eat.