Meat Physics – Part 2: Maillard Reactions in Cooking Meat

Fiorentina-con-patate-al-forno

This article is the sequel to Meat Physics – Part 1: To Cook a T-Boke Steak

In this second chapter we enter the details about chemical and physical processes taking place during the cooking of the Fiorentina Steak (T-Bone Steak). Our goal is to figure out how to get from raw meat to cooked meat.

A variety of chemical reactions determine the characteristics of cooked meat: aroma, the brownish colour and, obviously, the flavor. Some of these reactions are classified under the Maillard reactions.

Louis Camille Maillaird is a famous French chemist lived across the 19th and the 20th centuries. He discovered the chemical reactions among an amino acid and reducing sugars, while attempting to reproduce protein synthesis.

Let’s dive deep in more details, whilst not tangling up with difficult chemical formulas.

It is interesting to notice that Maillard Reactions take place not only during the cooking of meat, but also in the cooking process of onions, bread, French fries and toasted coffee.

The starting element of these kind of reactions is the amino acid reaction with sugar.

An amino acid is an organic compound with a basic structure formed by the integration of an amino group (nitrogen + hydrogen) with a carboxyl group (carbon + oxygen + hydrogen). Below, you can see an easy example of this. The “R” mark represents the amino acid part stretching to form bonds. Amino acids are the constitutive elements of every protein.

chimica della carne

For there are amino acids and sugars in different quantities in a great range of foods, Maillard reactions ought to create lots of final combinations, thus lots of different shades of cooking.

Try to think about your order at a restaurant: you will ask for a “well-cooked” meat or for an “underdone” meat. Have you ever received your dish with the same cooking?

We can give three different explanations of the Maillard reactions, resulting in three different stages of the reaction itself:

PHASE 1

In stage one, sugar carboxyl groups – formed by carbon compounds in double bond with oxygen, react with the amino acids amino groups. This reaction, catalyzed by the energy transition brought by the grill heat, produces glucosamine and water.

PHASE 2

Glusosamine is also a nitrogen, carbon, oxygen and hydrogen compound, but is an instable element that transforms rapidly, following the so called Amadori rearrangement. Details of  this rearrangement are complicated, what is important here is that at this stage typical cooked meat compounds are produced.

PHASE 3

In the third stage, rearrangements start to produce chitosamine, some ketose and amino groups compounds, furtherly reacting until they produce the final bonds. Among these, to mention one, the 2-bis-methyl-3-furyl-disulfide, whose presence determines the cooked meat fragrance: mouth watering just to think about it.

fiorentina griglia

As explained in the previous chapter, the final result of these three stages will be determined by the food quality we are cooking, the cooking temperature and the cooking time.

The necessary temperature to start the Maillard reactions is between 284 °F and 356 °F. Above this temperature, Maillard reactions still happen, but they produce the tipycal burning smell, not so pleasant as the cooked meat fragrance.

Traditional cooking recipes have it that meat has to be cooked for one minute near the heating source, in order to create the brownish crust (Maillard reactions are already happening here!), and to remove it and cook it 3 to 4 minutes per side and, at last, 5 to 7 minutes on the bone steak.

Now that we have looked at the reactions, we know that time is crucial just like the cooking heat. Indeed, that is why a long exposure to heat could create compounds that harden the meat, and an hurried cooking could not produce the compounds generating the specific meat aroma which we discussed above.

It’s up to the chef to develop specific abilities to adequate the cooking to the specific piece of meat he is about to cook.

Our ancestors back in the 15th century already knew all these things: they might not have called them “reactions”, and they sure knew nothing about carbon and amino groups and all that comes with that, but we owe them one important thing: we did not have to wait Louis Maillard to taste a fantastic Fiorentina Steak!

Fonti: Le scienze: il blogThe Science of Cooking (Peter Barham)

Matteo Biagetti | PhD Student @ Department de Physique

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