The Maillard reaction was discovered in 1912 by Louis C. Maillard when he observed the browning phenomena with aroma formation in a heated solution containing a sugar and an amino acid. The Maillard reaction starts from the reactions between carbonyl groups of various sugars and amino groups of amino acids/ proteins, following the formation of intermediate compounds or poly-carbonyl compounds, which further react with each other and amino acids/proteins. Through various chemical reactions such as condensation, polymerization, degradation, cyclization etc., color and aroma are formed. The imparting of brown color is mainly attributed to melanoidins. However, the chemical structure of melanoidins remains unclear because melanoidins are complex and heterogeneous polymers. On the other hand, various kinds of low-molecular-weight pigments formed through the Maillard reaction have been isolated and their structures have been identified. Even though the contribution of each pigment is small, the recognition of color is cumulative. In some case, these pigments form brown polymers or significantly contribute to the total color of a model solution. These chemically clear information gives us a novel aspect for an overview of browning or pigmentation through the Maillard reaction.

1912 年，Louis C. Maillard 发现了美拉德反应，当时他在含有糖和氨基酸的加热溶液中观察到褐变现象和香气形成。美拉德反应从各种糖的羰基与氨基酸/蛋白质的氨基之间的反应开始，随后形成中间体化合物或多羰基化合物，它们进一步与氨基酸/蛋白质发生反应。通过缩合、聚合、降解、环化等各种化学反应，形成颜色和香气。棕色的赋予主要归因于类黑素。然而，类黑素的化学结构仍不清楚，因为类黑素是复杂且异质的聚合物。另一方面，通过美拉德反应形成的各种低分子量颜料已经被分离出来，并且它们的结构已经被鉴定。尽管每种颜料的贡献很小，但对颜色的识别是累积的。在某些情况下，这些颜料会形成棕色聚合物或显着影响模型溶液的总颜色。这些化学上清晰的信息为我们提供了通过美拉德反应概述褐变或色素沉着的新方面。