Maillard reaction and caramelization

Maillard reaction and caramelization

The Maillard reaction, also known as non-enzymatic browning reaction, which is naming after French chemist Louis-Camille Maillard. However, there are two kinds of non-enzymatic browning reactions occur due to the sugars, involving caramelization and the Maillard reaction. Some examples of these reactions are grilled steaks and grilled onions taste, popcorns smell, and coffees aroma. The Maillard reaction is an extremely complex process, in which a reaction between reducing sugars and the monomers that build proteins, or amino acids*, occurs by the impact of heat. It starts with the reaction of a reducing sugar*, such as fructose and glucose with an amine, creating glucosamine ⃰. The Maillard reaction and caramelization are both promoted by heating, but the Maillard reaction involves amino acids with sugars, whereas caramelization is the pyrolysis of certain sugars, or in other simple words, the interaction of sugars with sugars.

High-temperature cooking speeds up the Maillard reaction because heat both increases the rate of chemical reactions and accelerates the evaporation of water. Another factor that affects the rate of the reaction is PH. According to Hodge’s model, the Maillard reaction has three stages. First, the carbonyl group of a sugar reacts with an amino group on a protein or amino acid to produce water and an unstable glycosylamine. Then, the glycosylamine undergoes Amadori rearrangements to produce a series of aminoketose compounds. Last, a multitude of molecules, including some with flavor, aroma, and color, are created when the aminoketose compounds undergo a host of further rearrangements, conversions, additions, and polymerizations₁. For example, 2-furfurylthiol is an organic compound that possesses a bitter taste of roasted coffee, methional has potato-like, sweet flavor, and vanillin is the primary component of the extract of the vanilla bean.

Caramelization is the removal of water from sugar, resulting in a high weight compound. In addition to requiring heat in caramelization reaction in order to begin, heat is produced while this reaction develops. The reducing sugars broke into smaller components through the heating, therefore, a tendency to donate electrons occurs, resulting in new compounds. Some of these compounds are responsible for the color of the developing caramel while others deliver its flavor or aroma.

Gelatin in crème caramel or jelly is important against osteoporosis, making the bones stronger and increasing the mineral density of the skeleton. Therefore, in some cultures, pregnant women after delivery, are given jelly to eat it.

*Each amino acid contains a central C atom, an amino group NH₂, a carboxyl group COOH, and a specific R group.

*A reducing sugar means having a free aldehyde group -CHO or a free ketone group RC(=O)R'. Thus, it gives some of its electrons to other molecules, working as a reducing agent.

*Glucosamine is a natural compound produced in the body and found in the cartilages, which are the tough tissues that cushion the joints. It can heal arthritis and use for osteoporosis, but enough evidences are not conformed, yet.

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References:

https://cen.acs.org/articles/90/i40/Maillard-Reaction-Turns-100.html ₁