I'm interested in food science, and I've been reading about Maillard reaction.

All of the articles / videos about Maillard reactions that I found online mention that reducing sugar and amino acids are required for the reaction to occur, but never talks about what kind of reducing sugars are present while searing a steak, roasting a chicken, etc.

When we are cooking a steak with just olive oil, for example, what kind of reducing sugars are present? I initially thought glycogen and ribose in the meat might be acting as reducing sugars, but I learned that most meat we buy don't have glycogen, and there is only a very small amount of ribose present in the meat. Similarly, what kind of reducing sugar / amino acid is present when baking bread?

Lastly, my understanding is that table sugar we buy from stores is sucrose, which is a non-reducing sugar. Does this mean that adding sugar while cooking meat wouldn't help if your goal is to start a Maillard reaction? I know that sucrose does break down to glucose and fructose, which are reducing sugars, when heat is added, but does that break-down occur fast enough for it to be meaningful?

Any input would be greatly appreciated!


1 Answer 1


Quoting from medium.com

If it wasn’t for Maillard, we would not have juicy seared steak, deep fried chicken wings, nor grilled sausages. All these browning, aromas and flavor bursts are a result of simple sugars reacting together with proteins. However, Maillard is not the only reaction occurring between these different molecules in food.

This is one of the chemical reaction that whether you have an interest in chemistry or not, we all carry out on a regular, maybe even in daily basis.The Maillard Reaction${^1}$ causes two types of browning of foods: enzymatic & non-enzymatic browning. Non-enzymatic browning can again be split in two types: the Maillard reaction and caramelization${^2}$.

The Proteins contained in meat and other comestible goods are usually rich in the amino acids arginine and lysine. The side chain func- tional groups of Arg and Lys react with reducing carbohydrates such as glucose or lactose to form Amadori reaction products${^3}$.

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Maillard reaction chemistry

The Maillard reaction is a chemical reaction between an amino acid and a reducing sugar, usually requiring the addition of heat.The Maillard reaction is a ‘non-enzymatic browning' reaction involving reduced sugars with compounds possessing free amino groups. A reactive sugar, such as glucose(a reducing sugar) can react with amino groups in amino acids, peptides, and proteins as well as with other molecules that contain free amino groups${^4}$.

Why a Reducing sugar?

Freshly prepared solutions of glucose in water gradually change by the opening of the pyranose ring to the free aldehyde form. This reaction is a reversal of a hemiacetal formation reaction. Reducing sugars behave like glucose${^5}$.

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Following are the steps involved.

  • Initial reaction between a reducing sugar and an amino group forms an unstable Schiff base${^6}$.

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  • The Schiff base slowly rearranges to form Amadori products${^7}$.

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Next, oxidative decomposition of Amadori products can lead to the formation of a wide range of reactive carbonyl and dicarbonyl compounds.The complex reactions are summarised in figure below${^7}$.

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Different amino acids produce different amounts of browning.

The Maillard reaction is responsible for many colors and flavors in foodstuffs${^8}$.

The Maillard reaction does not just make food taste better. It has a science involved in it. Understanding the key facts allows you to manipulate the process of cooking according to what your taste buds crave for. It is the difference between blindly following a recipe and being able to make a recipe work for your taste${^9}$.


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

The pentose sugars might be part of Nucleotide of DNA and RNA(In case no external reducing source is added).

That said, Reducing sugar free xylose, has been reported in onion, strawberries, prunes, apples, pears, grapes, juniper berries, barley malts, brewhouse worts, maple syrup, asparagus, the white and the yolk of eggs, corn, tomatoes, apricots, bamboo shoots, potatoes, beans, alfalfa, beer, and mangoes${ ^{10}}$.

Most of the carbohydrate of the carrot was found to be in the form of soluble reducing substance(You could try as additives for steak prepration)${^{11}}$.













  • 1
    $\begingroup$ Thanks for the resources! But the information above doesn't describe where the reducing sugars such as glucose is coming from. When cooking a steak with oil, where is glucose coming from? $\endgroup$
    – Sonul
    Jun 13, 2019 at 16:36
  • 1
    $\begingroup$ @Sonul I have update regarding reducing sugars in the post. $\endgroup$ Jun 13, 2019 at 17:24

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