What is the coffee Mena reaction? what is the Mena reaction? how much is the Mena reaction?

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The aroma of coffee comes from the fact that coffee beans themselves store rich precursors of aroma substances, such as carbohydrates, proteins, lipids, organic acids, etc. After being heated and baked, it will initiate a series of complex reactions, creating an attractive aroma. The two important reactions are caramelization (caramelization, oxidation and browning of sugars) and Mena reaction (Maillard reaction, the reaction of amino acids with sugars). Both reactions require the participation of sugars, and the rich sugar in raw beans provides the materials needed for these two reactions. Studies have also shown that there is a positive correlation between sucrose content and the aroma of coffee beans. Because the sugar content of Arabica mentioned in the previous paragraph is more than Robusta, it also proves the reason why Arabica coffee beans have a better flavor.

We all know that coffee cooked beans are delicious, but raw beans are tasteless. Do you want to know why? Why does food taste sweet when heated? In fact, this is the pyrolysis of food after heating, that is, the "Mena reaction". Want to know what benefits the Mena reaction will bring to the food? What problems will the Mena reaction bring you? Please take a look at the introduction to this article.

In order to change from raw coffee beans to coffee beans that can be drunk, the necessary step is "roasting" or, to put it bluntly, "scorched", because only roasted coffee beans can emit an attractive fragrance that mortals can't resist.

In the process of coffee bean roasting, the residual water in the coffee bean cell is converted into water vapor, but the thickness of the cell wall (not the soybean membrane cover) of the coffee bean is about 6 microns, which is not only much thicker than that of ordinary plants. and relative to its cell size of more than 30 microns, it is like a small pressure boiler when roasted at high temperature (the intracellular pressure can be as high as more than 20 atmospheric pressure). So the sugars, proteins, peptides, lipids and minerals inside the cell are caramelized at high temperature (185-240 ℃) and high pressure, which is known as the "Mena reaction". The end product is yellowish brown, bittersweet glycosylamine and melanin (the main source of coffee flavor), and carbon dioxide (up to 12 liters of carbon dioxide per kilogram of roasted coffee beans, wow! Greenhouse gases! Sometimes it breaks through the cell wall and produces the popping sound that is often heard in roasted coffee beans. From raw beans to the end of roasting, the volume of coffee increased by 50%, while the weight of coffee decreased by 20%.

It is because of the addition of "heat" that proteins and lipids with longer molecular chains inside raw coffee beans can be pyrolyzed into shorter molecules, just like cracking oil, while shorter molecules with lower molecular weights are more likely to volatilize. After roasting, the number of volatile compounds in roasted coffee beans increased from about 250 to 800, and more than 800 volatiles were released from the beans. These gases are the main components of coffee caffeol and the main source of coffee aroma.

In addition to the "temperature", another baking factor that affects the flavor of coffee is "time". The baking time depends on the baking temperature and the baking process, usually about 12 minutes, and some people use high temperature to reduce the baking time to 90 seconds. in addition, low-temperature baking can extend the time to 40 minutes, depending on the taste of the coffee beans, is a unique knowledge!

But exactly how much coffee should be roasted before OK is really a matter of opinion, and there will be specific preferences depending on the country in which you are located.

Although the roasting terminology and roasting degree differ, the roasting degree of coffee has a similar classification, just as steaks are distinguished by rare rare, medium rare medium rare, medium medium, medium well medium well and well-done well done. Generally speaking, it can be divided into four types: light baking, moderate baking, deep baking and double baking.