Brown Your Butter for The Better!
Written by Carson Seo
Edited by Renee Lee
Butter. The fat we all know and love can be enjoyed in a multitude of ways, whether by spreading it onto a piece of toast, adding it into cookie dough, or melting it into a pan to baste a steak. Butter is a versatile ingredient that is used to cook many of the foods we eat. Butter on its own provides additional richness to foods, but did you know that the flavor of butter can be greatly altered through burning it? The butter that remains after being heated to a high temperature is called browned butter. Browned butter gets its name from the fact that when butter heats up, the color of the butter changes, from white to a darker, more golden-brown color [1]. This darkening phenomenon the butter undergoes may appear intuitive, since the butter is being burnt in a sense, but examining further, this color change arises due to a multi-step chemical reaction, termed the Mailliard reaction [1].
The Mailliard reaction is a chemical reaction that occurs between amino acids and reducing sugars [2]. This reaction mechanism was originally discovered by a French chemist named Louis Camille Mailliard, when he noticed that a browning reaction occurred when a solution of a sugar and an amino acid was heated to a high temperature [4]. Amino acids are essentially chemical units that structure and make up proteins, consisting of an amino group (NH2), carboxyl group (COOH), and a variable side chemical group called an R group. Reducing sugars are defined as carbohydrates that contain an aldehyde group (CHO) within their chemical structures [3].
The Mailliard reaction begins with reducing sugars and amino acids being heated to a high temperature, specifically temperatures ranging from 140 to 165 degrees Celsius [2]. When reducing sugars and amino acids become heated, they can interact with each other. In particular, the carbonyl group present within the reducing sugar will react with the amino group of the amino acid, forming unstable products like a Schiff base or an Amadori rearrangement product [4], along with water [2].
Subsequently, the Schiff base quickly rearranges to form more stable compounds called ketoamines [2], which break down to produce products such as melanoidins [4], which contributes a nutty flavor as well as the brown color that the Mailliard reaction produces. On the other hand, Amadori rearrangement products are converted to a variety of reactive intermediates. Via several further chemical reactions, such as polymerization and cyclization, the reactive intermediates are converted to a class of compounds known as Mailliard Reaction Products, or MRPs, which are responsible for creating new, delicious aromas and flavors [4]. A diverse set of compounds are considered as MRPs, including peptides and sugars. An example of an MRP is furans [4], which is a compound that helps to form a nutty aroma in foods.
Now, you might be asking: how is the Mailliard reaction connected to creating browned butter? Butter is primarily made of milk, which contains proteins and sugars [5]. Within milk, casein and whey protein along with a reducing sugar named lactose are present, making up the bulk of the fluid [5]. Therefore, when butter becomes heated, amino acids within caseins and whey proteins can react with the lactose, allowing for Schiff bases and Amadori rearrangement products to be formed, and causing a Mailliard reaction to occur. The Mailliard reaction browns the butter and develops savory, nutty flavors and aromas, as well as a subtle sweet scent within the browned butter, creating a delicious, versatile condiment. Browning butter can amplify and increase the savoriness of regular butter. So, next time you are thinking of cooking food with some butter, consider browning your butter first!
Carson Seo ’30 is in the College of Agriculture and Life Sciences. He can be reached at gs826@cornell.edu.
