La Réaction de Maillard

The reaction discovered by Louis Maillard explains a great deal about the appeal of cooked foods.

If I told you that a French scientist working in the early twentieth century was responsible for the understanding of how a whole bunch of things you like to eat get the way they do when we cook them, would you be surprised? Louis Camille Maillard, (May-yard), was his name, and his work resonates throughout the kitchens of the world to this very day. What Maillard did was to explain why many foods turn brown, and why we like it when they do – La Réaction de Maillard.

Louis Maillard
Louis Maillard

For a guy who did such seminal work in the science of food, very little seems to be know about the man. He was born in 1878, in Pont-à-Mousson, a little town on the river Moselle, between Metz and Nancy, about 200 miles due east of Paris. Pont-à- Mousson was a village of roughly 8,000 souls in Maillard’s day. Since the late sixteenth century, there had been a Jesuit university there, with studies in theology, law, medicine, and the arts. The area was predominantly German speaking, and part of the Holy Roman Empire until 1766, when France claimed it and King Louie the Beloved moved the university to Nancy.
The town remained a center for the arts, sporting a bustling papier mâché factory. Located on a strategically important river crossing, Mousson was torn by war throughout the nineteenth and twentieth centuries. For such a tiny place, it sports more than its share of celebrity. In addition to Maillard, a saint, (Guarinus of Sitten), a Queen (Margaret of Anjou), a General (Geraud Duroc), and the inventor of the modern bicycle, (Pierre Lallement), all hailed from there.

Louie’s father was a medical doctor, his mother, a housewife. While there were professional bakers in the extended family, (who all hailed from the Lorraine region), nothing in the sparse information available regarding Maillard’s upbringing points to food. He began university studies at the tender age of 16, and excelled in mathematics and chemistry. He married in 1909 and divorced four years later, without producing any progeny. He never remarried; he was clearly bound to his work. I’ve never found anything to indicate if Maillard cooked, was particularly fond of eating, or ever realized that his work would so deeply affect food science. Look at the few photographs taken of him throughout his life, and you see a guy who looks like he ate because he had to, (although he did have a fabulous mustache).

Louis Maillard in his lab, circa 1915
Louis Maillard in his lab, circa 1915

His work was predominantly medical and physiological in nature. He studied the metabolism of urea and kidney function, and this research was fruitful toward better understanding and treatment of kidney diseases. In 1912, pursuant to this line of research, he began studying the reaction between amino acids and sugars. This work lead to his discovery of certain reactions, and was quantified as the Maillard reaction was named after him. He received a variety of scientific accolades, including the French Academy of Medicine award in 1914.

Maillard’s seminal work toward the discovery of the reaction that bears his name was focused on kidney function, specifically, the reasons why and how us humans pee in a variety of shades of yellow. He was curious about processes that would lead relatively clear substances to change color and produce CO2 when heated. His gut told him this would be important knowledge toward a better understanding of diabetes. Nothing he found initially would necessarily have lead him to a realization that his work would have bearing on food science for decades to come. After discovering his namesake reaction, he went on to other work, sometimes making rather sudden and pronounced changes in area and venue of study. One of these jumps occurred post WWI, when he left France altogether and began studying pharmacology. For all practical purposes, he gave up the life of research he’d been pursuing for a couple of decades. Maillard died in Paris in 1934, at the age of 56.

The heady scent of freshly baked bread owes its allure to the Maillard Reaction.
The heady scent of freshly baked bread owes its allure to the Maillard Reaction.

How does Maillard’s discovery segue to food? In more ways than you might imagine. Everything from the browning of meat to toasted bread, and much more – biscuits, frittes, roux, pretzels and crackers, dried and condensed milk, crusty bread, maple syrup, roasted coffee, dull de leche, and barley malted for beer or booze all speak to the human appetite largely because of the Maillard’s Reaction. Some of these specifically address color, but the lions share are tied to our senses of smell and taste.

Roasting coffee beans owe their allure to Maillard as well.
Roasting coffee beans owe their allure to Maillard as well.

And what of that science? Browning of food happens, in big picture form, one of two ways – one is enzymatic and the other, well, isn’t. The non-enzymatic branch narrows into three shoots, one of which is the Maillard Reaction. This occurs when a compound known as a carbonyl, (a functional group composed of a carbon atom double bonded to an oxygen atom, like for instance, sugar), reacts with an amino acid, peptide (AKA two or more linked amino acids), or a protein. The reaction process is rather complex, but in essence, heat is the catalyst that causes changes in those constituents, leading to browning and associated flavor and smells. Relatively high heat in cooking terms is usually required, although the reaction can occur at lower temperatures when concentrations of amino acids and sugars are high.

The Maillard Reaction
The Maillard Reaction

While browning tells us that many foods are cooked to a satisfactory level, it’s the smell of seared steak, freshly baked bread, roasting peanuts, or a dumpling being pan fried that really illustrates the power of Maillard’s discovery. Over the millennia that humans have cooked food, the process has gone from arcane knowledge to quite common, and yet the why behind the process remained hidden until the early 20th century – pretty fascinating, if you ask me.

Seared steak, it's all in the smell...
Seared steak, it’s all in the smell…

Yet it was the desire to better understand physiological processes within the human body that drove Maillard’s discovery, and his reaction does indeed occur within us. Studies have shown correlation between the reaction and degenerative eye diseases, diabetes, pulmonary fibrosis, and neuro-degenerative disorders.

I’m probably just being a romantic, but for some reason, I get a visual of Maillard, sitting at a little table is his lab, absently munching on a chunk of baguette, pondering his research, without realizing that his answer was literally in the palm of his hand, all along.

Author: urbanmonique

I cook, write, throw flies, and play music in the Great Pacific Northwet.

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