The Maillard Reaction
By Nancy Honig
The flavor and texture of vegetables can be influence by how they are cut and prepared. The difference between a whole baked sweet potato and baked slices of sweet potato can be very different. When more surface area is exposed to heat, this helps develop more natural sugars and caramel flavors. Cutting vegetables to roast or sauté, can take flavor to another level because of the Maillard reaction between the proteins, sugars and heat.
So what is the science behind this and why does it make food taste better? I will try to keep the explanation as simple as possible. Browning, or the Maillard reaction, creates flavor and changes the color of food. Maillard reactions generally only begin to occur above 285°F (140°C). Until the Maillard reaction occurs meat will have less flavor.
The Maillard reaction is a chemical reaction between an amino acid and a reducing sugar, usually requiring the addition of heat. Like caramelization, it is a form of non-enzymatic browning. This reaction is the basis of the flavoring industry, since the type of amino acid determines the resulting flavor. In the process, hundreds of different flavor compounds are created. These compounds in turn break down to form yet more new flavor compounds, and so on. Each type of food has a very distinctive set of flavor compounds that are formed during the Maillard reaction. It is these same compounds that flavor scientists have used over the years to create artificial flavors. It is interesting to note that The Maillard reaction is responsible for many colors and flavors in foodstuffs: caramel made from milk and sugar; the browning of bread into toast; the color of beer, chocolate, coffee, and maple syrup; the flavor of roast meat and the color of dried or condensed milk.
The Maillard reaction should not be confused with Caramelization which occurs with sugars. Caramelization is the oxidation of sugar, a process used extensively in cooking for the resulting nutty flavor and brown color. Caramelization is a type of non-enzymatic browning reaction. As the process occurs, volatile chemicals are released producing the characteristic caramel flavor. The reaction involves the removal of water (as steam) and the breakdown of the sugar. The caramelization reaction depends on the type of sugar. Sucrose and glucose caramelize around 160C (320F) and fructose caramelizes at 110C (230F).
Caramelization of sucrose starts with the melting of the sugar at high temperatures (see below) followed by foaming (boiling). Sucrose first decomposes into glucose and fructose. This is followed by a condensation step, in which the individual sugars lose water and react with each other. Hundreds of new aromatic compounds are formed having a range of complex flavors.
One of my favorite Food Networks Stars in known for say, “Brown food taste good”! It really does make a difference when you do things such as roasting your vegetables instead of boiling them or searing your meat before putting it in the oven or slow cooker to finish. Just remember that if carmelization is allowed to proceed to far the taste of the mixture will become less sweet as the original sugar is destroyed. Eventually the flavor will turn bitter.
Here is a simple recipe for fall vegetables the show how delicious a little browning can be!
Roasted Fall Vegetables
2 pounds (about 1 medium) butternut squash, peeled, seeded, and cut into 1 ½-inch pieces
2 pounds new red potatoes (12 to 14), well-scrubbed and quartered
1-pound medium red onions (about 2 to 3), peeled and quartered
1-pound carrots (6 to 8 medium), halved lengthwise, if thick, and cut into 1 ½-inch lengths
4 to 6 garlic cloves, peeled and smashed
3 tablespoons olive oil
Coarse salt and ground pepper
Preheat oven to 450 degrees. Divide vegetables and garlic between two shallow pans (such as baking sheets) and don’t overcrowd vegetables. This allows vegetables to brown rather than steam. You can line with parchment paper, if desired, for easy cleanup. Dividing evenly, toss with oil, 2 teaspoons coarse salt, and 1/4 teaspoon pepper. Roast until vegetables are tender and beginning to brown, 40 to 50 minutes, tossing them and rotating sheets from top to bottom halfway through. Serve hot.
