Harnessing the Maillard Reaction

A flavorful bread crust, the golden skin on a turkey, and roasted vegetables all have the same process behind their rich, complex flavor: the Maillard reaction, which combines proteins and sugars to create new flavors and browning. The Maillard reaction isn’t one reactions, but a set of chemical reactions that occurs when proteins and sugars are cooked at high heats. The reaction produces lots of tasty chemicals that color food brown and give the food complex flavors. In order to bring those flavors and colors to your food, you need to know how the reaction works.

What kinds of food experience the Maillard Reaction?

The Maillard reaction is a set of reactions between proteins and sugars. Sugars occur in some quantity in most foods, from chicken breast and cheese to broccoli and quinoa. This means that you don’t have to add sugar to your dish for the Maillard reaction to occur. While the reaction can occur in any food with proteins and sugars, it is prominent in food with a lot of protein and a smaller amount of sugar, like meats. For foods that have a lot of sugar and only some protein, like cookies, the Maillard reaction will occur, but most of the browning will come from caramelization, a separate reaction in sugar that doesn’t require protein. Caramelization will be discussed in a later section.

If you use different types of proteins, sugars, or other ingredients, you’ll get slightly different reactions in your food. This is why browning meat doesn’t smell the same as baking bread. Proteins can have a huge variety of structures. From differences in amino acids, the basic chemical building blocks of proteins, to differences in how long strands of amino acids fold and interact. Because proteins are different at the molecular level, they’re also difference in what we can perceive about them. Meats look different from egg whites and whey protein, for example. These differences in proteins at the tiny level lead to different tastes and appearances. See Figure 1 and Figure 2.

amino-acid_med
Fig 1. A generic Amino Acid. Different variable groups (R) create different amino acids (https://www.exploratorium.edu/cooking/meat/INT-what-makes-flavor.html)

 

folded_protein
Fig 2. An example of a folded protein. (https://en.wikibooks.org/wiki/Structural_Biochemistry/Proteins/Protein_Folding_Problem)

The sugars in the Maillard reaction can take many forms, from simpler sugars like glucose or table sugar to more complex sugars, like starch. Simple or complex in this case just means how much work the body has to do to turn the sugar into energy. Complex sugars must be turned into simple sugars before they can provide energy to your body. Wheat flour may not taste very sweet, but it has a lot of complex sugar in the form of starch. See Figure 3.

sugars
Fig. 3. Molecular structure of a few types of carbohydrates (sugars). (https://www.precisionnutrition.com/all-about-carbohydrates)

 

Differences in the ingredients of the Maillard reaction result in a different set of reactions taking place, even if the reactions are all still under the Maillard umbrella. These different reactions mean that foods you make with different ingredients will have different flavors,

What makes the Maillard Reaction occur?

The Maillard reaction occurs as a reaction between the protein and sugars in the presence of heat. The carbonyl group in the sugar reacts with the nucleophilic amino group in the protein. In slightly more plain terms, the part of the sugar that includes an oxygen molecule double bonded to a carbon molecule reacts with the part of an amino acid that tends to donate electrons in reactions. This is associated with a host of smaller reactions that have the colors and flavors associated with browning food as their products. If that went over your head, that’s okay! As a cook, you don’t have to worry about the details of the reaction. You just have to make sure that you have the right ingredients and condition for the chemicals to do their work.

Once the right ingredients are present, the most important factors to ensure that the Maillard reaction occurs are heat and dryness. The first factor is temperature. The reaction typically occurs between 300 and 500 degrees Fahrenheit, so ingredients must reach this temperature before the reaction occurs. The second factor is dryness. If your food is too wet, it will not get hot enough for the reaction to occur. Because water boils at 212 degrees Fahrenheit, food with a lot of water in it, or foods submerged in water cannot get above the boiling temperature of water. For example, look at the dumplings and rolls shown in Figures 4 and 5. Dumplings and rolls have essentially the same ingredients, but different temperatures and cooking methods make their final appearance and taste very different. The dumplings are essentially submerged in water during their cooking time, so they’re not able to get to the heat required for the Maillard reaction to occur. The reaction’s need for dryness is why cooks are often counseled to dry the surface of their meats before cooking.

 

dumplings
Fig. 4. Dumplings that have not undergone the Maillard Reaction (https://www.jocooks.com/)
rolls
Fig. 5. Rolls that have undergone the Maillard Reaction (http://cook.fnr.sndimg.com/)

Is the Maillard Reaction just another word for caramelization or burning?

While caramelization, burning, and the Maillard reaction all cause changes in color and flavor in foods, they are three separate processes. Caramelization does not require proteins at all, acting on sugars alone. It also occurs at higher temperatures than the Maillard reaction, starting when sugars reach about 350 degrees Fahrenheit. Burning produces blackened bits and acrid flavors rather than browning, and occurs at higher temperatures than the Maillard reaction.

Conclusion

Sometimes, cooking can feel very mysterious. Knowing why and how processes occur takes the confusion out of cooking, and puts you in control. Is your steak not browning? Turn up the heat and drain off the liquid! Does your meal feel plain? Add some roasted vegetables and crusty bread!

And before you sit down to a saved dinner, consider thanking the Maillard reaction.

REFERENCES

http://www.scienceofcooking.com/browning_of_foods.htm

http://www.scienceofcooking.com/maillard_reaction.htm

http://www.seriouseats.com/2017/04/what-is-maillard-reaction-cooking-science.html

http://modernistcuisine.com/2013/03/the-maillard-reaction/

 

 

 

 

 

 

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