I think it is a sad reflection on our civilization that while we can and do measure the temperature in the atmosphere of Venus we do not know what goes on inside our souffles. ― Nicholas Kurti.
The term molecular gastronomy was coined in the 1980s by Herve This, a French scientist, who is also the pioneer of the field that studies cooking not just as an art form, but as an exact science. He was partnered by a Hungarian professor of Physics, Nicholas Kurti in his endeavors. The term seeks to explain the reasoning behind the changes that occur in ingredients during various stages of cooking, and the chemical reactions that cause these transformations. Although several branches of study are dedicated to the scientific processes that are involved in specific industries such as canning or food packaging, there was practically no research conducted on what we call 'home cooking' or even food that was served in restaurants.
He chose to study these styles of cooking in depth, and is even rumored to have carried around a notebook in which he noted down the traditions in cooking, that were passed down from generation to generation and carried out without question, to understand whether there was a scientific explanation behind the results that were to be found. Although there is some amount of ambiguity about the term and the exact nature of its concern, the following is an attempt to explain a little more about this facet of culinary phenomenon.
As far as cooking goes, there's an age-old debate that rages on as to whether it is an art, a science, or a combination of the two. While there may be scientific reasons that contribute to the temperature that an egg coagulates, for instance, it still doesn't explain, why even after following the instructions of a recipe, it does not resemble the exact outcome. In the same vein, there exists the question that asks what it is that makes food taste the way it does, apart from the sensations that tickle the taste buds of sweet, salt, sour, and bitter.
There are obviously chemical changes that take place in foods in the process that changes them from the raw form to cooked, whether it is ions that are displaced, electrons mobilized, chain reactions, or some other obscure form of complex reactions that can explain the reasons that contribute to making a hamburger taste the way it does.
As any chemist worth his salt knows, small changes in weight or ingredients can completely change the outcome of a chemical reaction - as a somewhat exact science, the phenomenon in question attempts to apply the same logic to the process of cooking. That would, for instance, allow you, as a chef/chemist to concentrate the flavors of a given food substance in a form that need not necessarily conform to the external appearance of the ingredient from which the flavor is taken. For instance, you might be able to recreate the exact flavor of a bowlful of strawberries, cover it in a gelatinous coating, and serve it in a teaspoon.
In the current scenario there are a number of chefs who experiment with and continue to delve into the depths of what constitutes just the surface of this vast subject. Although the term was initially used to refer to the scientific exploration of the mysteries of cooking, it now is also loosely applied to a culinary style. In accordance, food prepared using this term is also served in a number of restaurants, the most famous of these being Alinea, elBulli, and The Fat Duck. As with all things new, this field has it followers and its foes. Its tremendous potential though, has yet to be properly exploited.