Caramel reaction (Caramelization) in coffee roasting

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I have told you that the three most important chemical reactions when roasting coffee beans are:

Maillard Reaction

Strecker Degration

Caramelization

With regard to Maillard Reaction, I have written related articles about its reaction principle and its flavor. About Maillard reaction, you can read my article 🔗 academic sharing: Yunnan coffee cooked bean main components analysis article related to the theory of Maillard reaction.

The above three reactions belong to non-enzymatic reaction in the process of roasting raw coffee beans. It's a completely different reaction than when you take a bite of the apple and turn brown.

Stryker degradation reaction is one of the three major chemical reactions in coffee roasting. It occurs between Maillard reaction and caramelization reaction. Only when raw coffee beans undergo Maillard reaction will Starlek degradation begin. The reaction includes amino acids, but unlike Maillard's reaction, which is a chemical reaction between molecules with two carbonyl groups and sugars in coffee beans, the chemical equation is as follows:

Strecker Degration refers to the interaction of carbonyl compounds of amino acids (proteins) in the water environment to produce aldehydes or ketones, as well as carbon dioxide. This reaction, also known as browning reaction, is the residue of Maillard reaction to react again.

These compounds begin to exchange their own parts, and a carbonyl terminates on the amino acid (the acid of the carbon lost from the chain) to aldehydes and aminoketones. This is an intermediate stage, and the reaction continues to create many different volatiles.

Today, Huaxia focuses on caramelization. When it comes to caramel, people subconsciously think that caramel is sweet. In fact, the caramelization reaction refers to the burning of reducing sugar in raw coffee beans. Caramel is not sweet, it is bitter.

As we all know, the raw beans begin to dehydrate after entering the pot, the yellowing period begins Maillard reaction, and the caramelization reaction begins after Maillard reaction. He needs a higher temperature than Maillard's reaction, about 150 to 180 degrees Celsius. The only raw material for caramelization is sugar. In the state of high temperature, the sugar is converted into furfuryl alcohol, which produces the scorched smell of sugar and the smell of meat to people's taste. The route of caramel reaction is different from Maillard reaction, but more volatile directional compounds are produced during caramel reaction than Maillard reaction due to the increase of temperature.

After a long period of high temperature, the caramelization reaction produces more aroma and is easier to identify artificially in the baking process. However, due to the lack of sulfur and nitrogen ions in the amino acid during the caramelization reaction, compared with Maillard reaction, the flavor of Kang Shifu braised beef can not be produced.

The caramelization reaction usually occurs when the coffee bean is about to end the Maillard reaction and is close to the second explosion. If you really want to know more about the properties of caramelization, you can prepare a pot of sugar water and cook it on a gas stove, which is initially only sweet and has no other directional substances. As the temperature increases, the caramelization reaction begins, and the sugar water becomes more sour, but more aroma is developed. This is the principle of the caramelization reaction. The stronger the caramel reaction, the less sweetness in the coffee. Therefore, some pretending to force criminals to drink deep-baked Espresso can drink sweet, pure self-deception.