The Chemistry of Steak

Introduction

YouTube Video



Steak is any cross-cut slab of meat, usually beef, that is between 1-2 inches thick that is meant to be cooked with relatively high heat quickly. It is considered to be one of the most popular and most American meals to have, not to mention one of the tastiest when it is cooked perfectly. There are several ways steak can be cooked; it can range from remaining very red and rare or cooked so that the brown that is seen on the outside of the finished steak goes all the way through the meat.

 

I chose to examine steak for a couple different reasons. First of all, it is one of my favorite meals that my father makes for our family. Not only is it one of my personal favorites, but it is also a favorite of my immediate family as well as many members of my extended family. Secondly, the process of cooking a steak and how to make it rare or well done has also interested me. People’s different preferences on how they want their steaks cooked also fascinates and sometimes even amuses me when they have very strong opinions on how cooked their steak is.

 

Steak does not have a huge affect on my life because my father generally saves it for special occasions such as a Christmas Eve dinner or a birthday. But throughout my life I have eaten steak cooked at various levels and have developed my own opinion on how a steak should be cooked (rare, and I mean as rare as possible, is the only way to go my friends). It has often been one of my favorite treats, and as a meat lover, steak will always be one of my favorite meals to have.



Composition of ...

  • Water

    • H2O

    • Makes up about 75% of animal muscle (steak)

  • Protein

    • General Formula: RCH(NH2)COOH

    • Includes

      • Carbon

      • Nitrogen

      • Oxygen

    • Makes up about 20% of animal muscle


Main Chemicals, Compounds, Components

  • Water (H2O)

Water is the necessity of all life. When scientists are searching for life, they search

for water. It makes up most of every living thing on Earth; even the Earth itself is made of mostly water. Its density and viscosity make it ideal for swimming as well as make blood circulation possible. Water can be used for cooking, drinking, cleaning, playing, and even creating electricity. It is predictable, measurable, and quantifiable. Water also has a darker side to it. It can kill, torture, and make things rust, as well as find small cracks and seep in uninvited. Water is needed and used in our everyday lives.

  • Protein (RCH(NH2)COOH)

Proteins are a macromolecule that makes up approximately 20% of all animal muscle. They

are composed of chains of amino acids. There are twenty different amino acids that can

combine to make different proteins depending on the organism’s DNA. Because DNA

cannot leave the cell’s nucleus, it will go through a process called transcription where it

will turn into mRNA (messenger RNA) that will be able to leave the nucleus and become

tRNA (transfer RNA). It will then go to a ribosome where it will go through a process

called translation. At this point, the tRNA will be coded to certain amino acids, which will

form proteins.



Chemistry's Role

The cooking process of steak happens through the Maillard reaction, also called the “browning reaction”, which is a complex series of reactions that has been studied for nearly a century; however, there are still many pathways and reactions that are unknown because of its complexity. Generally, the Maillard reaction is a chemical reaction where sugars and amino acids in the meat react to heat and create new and flavorful compounds. It is a reaction that is found occurring not only in steak, but also in toast and French fries. Factors that affect the different resulting flavors include pH, the types of amino acids and sugars, temperature, time, the presence of oxygen, and amount of water. Having a high water environment restricts the reaction because the reaction produces water.

The Maillard reaction occurs most readily between temperatures 300°F-500°F. When the meat is cooked, the outside temperature becomes hotter than the inside, which triggers the reaction. Protein molecules in the meat are bonded in coils and when heat is applied, those bonds begin to break and the coils begin to unwind. Most of the water content in the muscle fibers then leak out. Reactive carbonyl groups of the sugars react with the nucleophilic amino acids, which produces glycosylamine and water. Pentose sugars react more than hexoses, which in turn react more than disaccharides. The larger the sugar is, the slower it will react with the amino acids. For example, the amino acid lysine reacts the fastest and creates darker colors and the amino acid cysteine (with a sulphur group) creates specific flavors but not a lot of color. The unstable glycosylamine that comes from the initial reaction of the sugar and amino acids then goes through Amadori rearrangement, forming ketosamines. From there, the ketosamines can do several things such as produce water and reductones, short-chain hydrolytic fission products can be formed (Ex: diacetyl, aspirin, pyruvaldehyde), and produce brown nitrogenous polymers and melanoidins. Another thing that is happening in the reaction is iron atoms in the proteins are losing an electron, which causes the gradual color change of the meat. Some people put sodium chloride (table salt) on the steak and allow it to sit prior to cooking, which pulls off moisture and speeds up the Maillard reaction; however, this does not make much of a difference in cooking time, but it may allow the seasoning to penetrate the outer layers of the steak.


Background Research

The Maillard reaction was originally discovered by French scientist Louis-Camille Maillard in the early twentieth century when he was trying to figure out how amino acids formed proteins. He saw that when he heated sugars together, the mixture would slowly turn brown. But it was not until the 1940s that people began to see a connection between the Maillard reaction and flavor when World War II soldiers complained about their powdered eggs turning brown and developing unappetizing flavors. After many laboratory tests, scientists discovered that the flavors were coming from the Maillard reaction and they began to research ways to prevent the reaction. Eventually, they discovered the role the Maillard reaction plays in developing aromas and flavors.

Resources

http://www.livescience.com/44852-cook-perfect-steak-science.html

What the Maillard Reaction is

Surface Temperatures Needed for Reaction

Purpose of Salt

http://www.exploratorium.edu/cooking/meat/INT-what-makes-flavor.html

Temperatures at which Maillard Reaction most Readily Occurs

History of Maillard Reaction

http://www.science.ie/features/archived-feature-articles/chemistry-of-cooking.html

Components of Animal Muscle

Things that happen in the Maillard Reaction

https://en.wikipedia.org/wiki/Maillard_reaction

Temperatures at which strictly Maillard Reaction Occurs

What happens when Temperatures are Higher than Maillard Reaction Temperatures

Things that happen in the Maillard Reaction

How the Maillard Reaction is Related to the Flavoring Industry

http://www.food-info.net/uk/colour/maillard.htm

The Complexity of the Maillard Reaction

Factors that Affect the Resulting Flavors from the Reaction

Specific Examples of Which Amino Acids Create What Flavors/Colors

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

Specific Examples of Which Amino Acids Create What Flavors/Colors

Restrictions on the Reaction

Other Sources

http://abyss.uoregon.edu/~js/glossary/proteins.html

https://en.wikipedia.org/wiki/Mineral



About the Author
Hannah Stevens is a junior at Billings Senior High School in Billings, Montana. She enjoys swimming competitively and has swam for Senior High ever since her freshman year. Hannah has competed on the varsity team, gone to state and lettered in swimming both her freshman and sophomore years. She is competing on the varsity team now and plans to go to state and letter in swimming once again this year. Hannah also has high aspirations for times for this season as well. She has received academic all-state in swimming as well both her freshman and sophomore years and will be continuing to work hard in the classroom to maintain her high GPA.







Comments