What is the Maillard Reaction? Mention Factors that Affects Maillard Reaction
Maillard reaction produces flavour and aroma during cooking process and it is used almost everywhere from the baking industry to our day to day life to make food more enticing and tasty. From freshly baked bread to grilled meat and roasted coffee, this reaction plays an essential role in making food more appealing and delicious.
The Maillard reaction is a chemical reaction between amino acids (from proteins) and reducing sugars (such as glucose or fructose). When food is exposed to high heat, the carbonyl group of the sugar reacts with the amino group of the amino acid. This process is accelerated in alkaline (basic) conditions. This reaction is often called nonenzymatic browning reaction because, it takes place in the absence of enzyme unlike many biological processes in living organisms.
While the Maillard reaction enhances flavour, it can also lead to the formation of compounds that may have negative health consequences.
Maillard Reaction also occurs at a much slower rate in our bodies, and it may have a role in the formation of some types of cataracts. It's also been linked as a contributor to other medical conditions.
For example, advanced glycation end-products (AGEs), formed during the Maillard reaction, compounds linked to aging and chronic diseases such as diabetes.
Uncontrolled Maillard reactions can produce acrylamide, a potential carcinogen which forms in starchy foods cooked at very high temperatures (e.g., fried potatoes, chips).
The reaction was first described in 1912 by the French chemist Louis-Camille Maillard. Later, in 1953, American chemist John E. Hodge proposed a detailed mechanism to explain its steps.
Mechanism: In 1953, American chemist John E Hodge published a mechanism for the different steps of the reaction. The reaction starts with the formation of an N-substituted glycosylamine and water, as the sugar and amino acid react. This unstable glycosylamine then undergoes Amadori rearrangement, forming a more stable ketosamine. Further reactions lead to a complex mixture of compounds, including melanoidins, which contribute to the brown colour and unique flavors.
Factors Affecting the Maillard Reaction
✍︎ Temperature: The reaction is initiated at temperatures above 140°C. High temperature increases the rate of chemical reactions and accelerates the evaporation of water.
✍︎ pH: The pH of the food can affect the reaction rate and the types of compounds formed. Reaction occurs rapidly in alkaline medium.
✍︎ Reactant concentration: A higher concentration of reducing sugars and amino acids accelerates browning.
✍︎ Time: Longer heating produces deeper colours and more intense flavours.
✍︎ Presence of Catalysts: Metal ions, acids, and bases, can act as catalysts and either speed up or slow down the Maillard reaction.