Maillard reaction
Chemical reaction between amino acids and reducing sugars creating browned food flavors.
The Maillard reaction is a chemical reaction between amino acids and reducing sugars that produces melanoidins, the compounds responsible for the browned color and distinctive flavor of many cooked foods. This non-enzymatic browning process typically proceeds rapidly from around a certain elevated temperature, and many recipes specify an oven temperature high enough to ensure it occurs. It is named after French chemist Louis Camille Maillard, who first described it in 1912 while attempting to reproduce biological protein synthesis. In 1953, chemist John E. Hodge established a mechanism for the reaction. The reactive carbonyl group of the sugar reacts with the nucleophilic amino group of the amino acid, forming a complex mixture of poorly characterized molecules that generate a range of aromas and flavors. This process is accelerated in an alkaline environment, such as when lye is applied to darken pretzels, because the amino groups become deprotonated and more nucleophilic. At higher temperatures, caramelization—a distinct browning of sugars—and pyrolysis, the final breakdown leading to burning and acrid flavors, become more pronounced. Additionally, at high temperatures, a probable carcinogen called acrylamide can form, which can be discouraged by heating at a lower temperature, adding asparaginase, or injecting carbon dioxide. The Maillard reaction produces hundreds of different flavor compounds depending on the food’s chemical constituents, temperature, cooking time, and air presence, and these compounds often break down to form yet more flavors. Flavorists have used this reaction to create artificial flavors, with most patents related to meat-like flavors. According to Nobel laureate Jean-Marie Lehn, it is the most widely practiced chemical reaction in the world. The reaction is responsible for the browning of seared meats, fried dumplings, cookies, bread crusts, toasted marshmallows, falafel, fried onions, coffee roasting, French fries, malted barley in whiskey and beer, dried and condensed milk, dulce de leche, black garlic, chocolate, and roasted peanuts. Specific compounds like 6-acetyl-2,3,4,5-tetrahydropyridine give baked goods a biscuit-like flavor, while 2-acetyl-1-pyrroline contributes to the smell of cooked rice and pandan. In archaeology, the Maillard process occurs slowly in acidic peat bogs, preserving bodies by browning skin and turning hai
- field
- Chemistry
- nationality
- French
Lore & Background
The Maillard reaction is a chemical process between amino acids and reducing sugars that produces melanoidins, the compounds responsible for the browned color and distinctive flavor in a wide range of cooked foods, including seared steaks, bread crusts, toasted marshmallows, and fried dumplings. It is a form of non-enzymatic browning that proceeds rapidly at elevated temperatures, though at higher heats, caramelization and pyrolysis become more pronounced. The reaction involves the carbonyl group of a sugar reacting with a nucleophilic amino group from an amino acid, forming a complex mixture of molecules that generate numerous aromas and flavors. This process is accelerated in an alkaline environment, such as when lye is applied to pretzels to darken them. Hundreds of different flavor compounds can be produced depending on the food’s chemical makeup, temperature, cooking time, and air exposure. The reaction is also responsible for the browning and umami taste in fried onions, coffee roasting, malted barley, dried and condensed milk, dulce de leche, black garlic, chocolate, and roasted peanuts. Specific compounds like 6-acetyl-2,3,4,5-tetrahydropyridine contribute a biscuit-like flavor in baked goods, while 2-acetyl-1-pyrroline gives cooked rice and pandan their characteristic smells. At high temperatures, a probable carcinogen called acrylamide can form, which can be discouraged by lower heat, adding asparaginase, or injecting carbon dioxide. The Maillard reaction also occurs in dried fruit, aging champagne, and in archaeological contexts, such as preserving bog bodies through slow browning in acidic peat.
Reader's Guide
The Maillard reaction is significant because it is responsible for the browning and flavor development in a vast array of foods, including seared steaks, fried dumplings, cookies, breads, toasted marshmallows, and falafel. It produces hundreds of different flavor compounds depending on the food's chemical constituents, temperature, cooking time, and presence of air. The reaction is accelerated in an alkaline environment, such as when lye is applied to darken pretzels. At high temperatures, a probable carcinogen called acrylamide can form, which can be discouraged by heating at a lower temperature, adding asparaginase, or injecting carbon dioxide. According to chemistry Nobel Prize winner Jean-Marie Lehn, 'The Maillard is, by far, the most widely practiced chemical reaction in the world.' The reaction also occurs in non-food contexts, such as in archaeology when bodies are preserved in peat bogs, and contributes to the preservation of paleofeces.
Did You Know?
- At higher temperatures, caramelization and pyrolysis become more pronounced, distinct from the Maillard reaction.
- Acrylamide, a probable human carcinogen, can be generated as a byproduct of the Maillard reaction between reducing sugars and the amino acid asparagine.
More in Cooking Techniques 1-24
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record