The Maillard reaction, named after L. C. Maillard, is also known as nonenzymatic browning. It is an extremely complex process and is the reaction between reducing sugars and proteins by the impact of heat.
The history of Maillard reactions begins in 1866, when Hugo Schiff (1834-1915) published that aldehydes (including sugars) react with amines (including amino acids) to form dark compounds. He proposed the formation of secondary imines (today called Schiff's bases) from aldehydes and aromatic amines. The reaction between carbonyl compound and primary amine discovered by Hugo Schiff in 1864 gave basis for further research in various scientific fields and resulted in thousands of papers being submitted by scientists all over the world to a diverse spectrum of scientific magazines.
In 1871, R. Sachsse studied the reaction of lactose with aniline, before Emil Fischer investigated the reactions of sugars and amino compounds in 1884 and 1886. Fischer focused on the reactions of D-glucose, D-fructose or sucrose with phenylhydrazine. Maillard was interested in Emil Fischer’s synthesis of peptides, which he thought, correctly as it turned out, could be achieved under milder conditions by the use of glycerol.
In 1909, Maillard began his studies. They are summarized in his 1913 academic report, under the title "Genèse des matières protéiques et des matières humiques”. He wrote at least eight related papers, with findings including carbon dioxide release as amino acids broke down, and the formation of a brown pigment.
He observed the formation of yellow-brown pigments in the reaction among sugars and amino acids, polypeptides, or proteins; and among polysaccharides and polypeptides, or proteins, in a heated solution.
Maillard searched for milder conditions. Thus, he wished to condense amino acids by use of glycerol as a condensing agent. He thus obtained cycloglycylglycine and pentaglycylglycine. Then, he used sugars instead of glycerol to investigate the formation of polypeptides from amino acids.
It was found that the aldehyde group (of an aldose) had more intense effect on amino acids than did the hydroxyl groups. This led to the discovery of the browning reaction, which is now more commonly known as the Maillard reaction.
At first, combining amino acids and sugars was simply called browning, and scientists only started calling it the Maillard reaction around 1947. In 1953, the US Department of Agriculture’s John Hodge proposed detailed mechanisms, breaking the Maillard reaction into three steps: the early Maillard reaction, the advanced Maillard reaction, and final Maillard reaction.
History of Maillard reaction
