Coffee is a unique natural product, consisting of more than 100 components and more than 2000 substances. Each variety has its own special set of elements that affect the shades of taste and aroma. The chemical composition of coffee in the form of grains and in the form of a finished drink is noticeably different, there is a difference between ground and instant drinks. Scientists around the world are exploring coffee beans, but despite all the possibilities of laboratories, it is still not possible to recreate synthetic coffee that would not differ from natural. So, what are coffee beans and instant coffee made of?

Diagram - chemical composition of coffee bean

Basically, a green coffee bean is made up of fiber, water, and coffee oils. The remaining 25% is caffeine, protein, mineral salts, the antioxidant chlorogenic acid (forms the astringent taste of coffee) and the alkaloid trigonelline (creates a unique aroma when roasted).

• More than 50% of green coffee contains carbohydrates (sugars and fiber). It is they who form the foam in espresso and make up the so-called body of the drink.
• Coffee contains many acids, and most of them are released during the heat treatment process. They have a positive effect on the functioning of the stomach and digestive system.
• Tannins form a bitter, slightly astringent taste. Dairy products (milk or cream) partially bind tannins and make the taste of the drink less bitter.
• Caffeine invigorates, helps to concentrate, slightly increases blood pressure and activates the work of all body systems. Different varieties of coffee have different amounts of caffeine (there is more in Robusta than in Arabica), and in addition, the place of growth and the method of processing the grain also matter.

In coffee, there is always the so-called coffee ash, which consists of potassium, magnesium, calcium, sodium and manganese.

Table of changes in the chemical composition of coffee during roasting

The roasting of coffee beans triggers many processes during which the composition of the coffee bean changes. The longer the roast goes on, the bigger the changes will be.

• Water. Water from the grains actively evaporates (from about 12% to 3%), and the content of other substances in terms of the changed mass increases.
• Sahara. In the process of roasting, they are caramelized, which causes Brown color.
• Cellulose. Breaks down into acids, alcohols, amino acids.
• Fats. Partially decomposed into acids.
• Caffeine. Its amount almost does not change, but as the grain loses moisture and the concentration of dry components increases, the amount of caffeine in roasted coffee is higher in relative content than in green coffee.
• Chlorogenic acid. Its amount during roasting is greatly reduced, but remains large enough to form aroma and bitter taste.
• Trigonneline. One of the most important alkaloids, during heat treatment, releases valuable vitamin PP, that is, nicotinic acid.

During roasting, the components of the grain not only break down into large quantity compounds, but also react with each other, forming new (usually volatile) components. As a result, a special taste and aroma is formed.

Oily volatile compounds are rather fragile, and even in the absence of air, their concentration decreases. Therefore, it is important to buy freshly roasted coffee and store it in small closed containers.

The chemical composition of instant coffee

In instant coffee, only 15-20% of the constituents are derived from natural coffee. Espresso is prepared in just 30 seconds, and coffee beans for instant coffee are sometimes boiled for 5-10 hours. At the same time, all useful, aromatic and flavoring substances remain in the thick, which is not used. Basically, only caffeine and some acids pass. The remaining 80% of the composition are flavors, stabilizers, dyes, preservatives, flavor enhancers. Cheap instant coffee makers can add ground chicory, grains, and more that aren't listed on the packaging.

No manufacturer will make instant coffee from "100% Alpine Arabica", as is sometimes written on the packaging. As a maximum, broken and damaged grains will go there. And then, most often it is Robusta, which has more caffeine.

Vitamins and minerals in the chemical composition of coffee

Natural coffee is rich in many vitamins and minerals useful for humans.

B3- a vitamin obtained from trigonelline during heating. It has a positive effect on the nervous system, normalizes metabolism.

BUT- a vitamin that affects the growth and development of all organs.

D- improves the absorption of nutrients in the intestines;

E- stimulates the immune system, positively affects the reproductive system.

Potassium, magnesium and calcium are good for the heart, improve the functioning of the brain and blood vessels, strengthen the bone and muscle systems.

Output

• Coffee is one of nature's most complex foods, containing over 2,000 compounds when roasted.
• Natural coffee in small doses has a positive effect on almost all body systems.
• Instant coffee is not good for the body, contains a minimum of vitamins and oils, but includes synthetic additives.

Raw coffee beans primarily contain caffeine, trigonelline, chlorogenic acid, protein, and mineral salts. This set of substances makes up a quarter of the mass of raw grain. The rest comes from fiber, coffee oil and water.

Caffeine is a member of the alkaloid group. It is caffeine that coffee owes its invigorating effect. In its pure form, caffeine was isolated from coffee beans in the 1920s. Caffeine has the appearance of colorless crystals with a bitter taste.

Trigonelline is also an alkaloid found in coffee beans. Unlike caffeine, it does not have a stimulating effect on the human body, but the taste and smell of roasted coffee beans depend on it.

Chlorogenic acid is one of the most valuable components of the composition of coffee beans.

Natural unroasted grains are the only natural product with a high content of chlorogenic acid. By stimulating the human digestive system, chlorogenic acid, which is part of green coffee beans, helps the body break down fats, which is why nutritionists around the world recommend green coffee beans for weight loss. When coffee beans are roasted, the content of chlorogenic acid is reduced by 2-3 times, and coffee acquires a characteristic, slightly astringent taste.

It should be added that coffee beans contain more than 30 different organic acids (including malic, citric, acetic and coffee acids). In addition, coffee beans contain healthy fatty acids:

• linoleic - 52.2-54.3%;
• palmitic - 26.6-27.8%;
• oleic - 6.7-8.2%;
• stearic - 5.6-6.3%;
• arachidonic - 2.6-2.8%;
• linolenic - 2.2-2.6%;
• behenic - 0.5-0.6%.

Despite such an abundance of useful substances, natural grain coffee is not a high-calorie product, although it contains proteins - 0.2 g, fats - 0.6 g and carbohydrates - 0.1 g from natural grain no more than 1 -2 Kcal. Nicotinic acid and vitamin PP contained in coffee beans are active biological components. That is why coffee is considered low-calorie and not capable of harming the human figure.

However, do not forget that the daily serving of coffee from natural beans should not exceed 0.3 g of caffeine, which corresponds to two teaspoons of ground coffee beans per glass of water, and taking 4 cups grain coffee per day, this is 1 g of caffeine, a person develops a constant need for coffee, comparable to alcohol addiction.

In nature, everything is carefully thought out. And the coffee bean is one of her most complex creations. For hundreds of years, scientists have been trying to uncover all the constituent components of grain, evaluate their effect on humans and synthesize them under artificial conditions. What substances in the composition of coffee occupy the largest share and how do they affect a person?

Chemistry of the coffee bean

Today, chemists from many well-known laboratories are still researching coffee beans. This is not just curiosity, but the desire to accurately determine the composition of coffee, its change depending on the degree of heat treatment, in order to make the drink more useful and rich in taste and aromatic properties in the future.

From the point of view of the layman, the most main component coffee and tea - caffeine. Scientists agree with this. This alkaloid in terms of dry matter is from 1 to 2.5% of the total mass of the grain, which is a fairly significant proportion.

It is caffeine that the drink owes to the invigorating and stimulating effect of the nervous system. This is due to the ability of caffeine to inhibit the action of relaxing receptors and activate the excitatory ones in the cerebral cortex. As a result, the desire to sleep, rest, lie down disappears, instead of which vivacity appears and efficiency increases. Of course, the effect of caffeine is temporary and after a few hours the body will still require the portion of rest it needs.

The content of the alkaloid in the composition of the coffee bean varies depending on the variety and the region where the trees grow. Robusta usually contains more caffeine than Arabica, so the taste of the drink, which is dominated by this type of coffee, has a pronounced bitterness and astringency. A record high caffeine content was recorded in Robusta from Guinea - 1.7%. Under the influence of high temperatures, caffeine is practically not destroyed and its amount remains unchanged. For the first time, the alkaloid was synthesized in the laboratory in the middle of the 19th century and became a component of many headache pills.

Another representative of the alkaloids is trigonelline. It does not have a stimulating effect on the nervous system, but contributes to the saturation of the grain palatability. When roasted, it breaks down into a number of less complex compounds, which also contribute to the appearance of the characteristic aroma of coffee.

Chlorogenic acid is one of the most valuable components among phenolic compounds. Natural unroasted grain is the only known natural product with a high content of it. It affects the functioning of the human digestive system, in particular, is involved in the breakdown of fats, which is why green coffee is so popular among those who lose weight. When grain is roasted, the acid content decreases by 2-3 times due to its decomposition into other less valuable components. Some of them affect the color of the roasted beans.

Nicotinic acid as a representative of B vitamins and vitamin PP are the only active biological components of their kind. They are involved in metabolic processes and regulation of nervous activity. These vitamins under the influence of high temperatures reduce their concentration.

There are only 1 calorie in a cup of invigorating drink without milk.

The chemical composition of coffee is about 30 types of organic acids, some of which practically do not undergo transformations during roasting and are involved in the formation of a healthy metabolism.

Essential oils and caffeol are complex components, including more than 200 compounds, which provide the grain with a multifaceted aroma. Attempts by scientists to synthesize caffeol in the laboratory have not yet yielded results, which indicates the real complexity of these compounds.

Tannins are complex organic substances that give coffee bitterness. The natural unroasted product contains up to 9% tannins, while the finished product contains only about 1%. In addition to taste, tannins give the grain a brown color, undergoing transformations into dark pigments. As a result of strong Italian roasting, the tannin content can be very negligible, which makes the taste of the future drink simple and even empty. If you add milk or cream to the cup, they bind tannins and neutralize their bitterness.

The proportion of the main components in terms of dry matter

natural grain or ground coffee is not a nutritious and high-calorie product, although it contains:

• proteins - 0.2 g;
• fats - 0.6 g;
• carbohydrates - 0.1 g.

The calorie content of a cup of a finished drink made from natural grain coffee does not exceed 1-2 Kcal. That is why the product is considered low-calorie and not capable of harming the figure. Coffee also contains iron, phosphorus, calcium and potassium.

What happens to the components found in coffee when roasted? Heat treatment of green grain is carried out in order to remove moisture from it and extract sugars and essential oils, which provide the grain with a characteristic color, taste and aroma.

What kind of transformations undergo grain components?

• The amount of water is reduced from 11% to 3%.
• Isolation of glucose and its caramelization.
• Complex polysaccharides are converted into water-soluble carbohydrates.
• Caffeol is formed - the most complex component, consisting of more than 220 compounds.
• Trigonelline is converted to nicotinic acid.
• The share of chlorogenic acid is reduced by an average of 65%.

The black color of the coffee bean may indicate that it has been subjected to the most intense heat treatment and possibly partial charring of the sugars occurred. Such coffee will not be tasty and fragrant.

The stronger the roast, the less nutrients are retained in the grain.

If we talk about the composition of instant coffee, then it is less rich in valuable components. It releases a high dose of caffeine and resinous substances, while phenols, acids, vitamins and other useful organic compounds are lost during the production process. Chem. the composition of the sublimated product is slightly richer than the usual soluble product due to the characteristics technological processes production.

Composition of different coffee drinks

Coffee as a product available to a wide range of consumers on the Russian market is represented by such brands as:

• Jacobs (Monarch);
• Jockey (in Turkish, classical, in Viennese);
• Nescafe (Classic);
• Lavazza (Cremo, Espresso);
• Cibo;
• Jardin.

Most of them have an Arabica of Brazilian origin called Santos, which is blended with other varieties and Robusta. The world famous Italian brand Lavazza works with rarer varieties of coffee, although it also buys Brazilian products to improve the taste of its original blends. There are varieties of coffee that, during roasting and further preparation of the drink, give a pleasant chocolate aroma and taste. They contain special essential oils, which provide the product with notes of cocoa in the aroma. Coffee in capsules for a coffee machine does not differ in composition from grain.

The composition of coffee as a finished drink depends on its type. Today, there are dozens of recipes for making coffee from the beloved by many Cappuccino and Glace to the rare Bicherin. The ingredients of the drink can be very different from regular or whipped cream, Amaretto to exotic liqueurs and spices. The figure below shows the composition of coffee prepared according to different recipes. This list can be supplemented by French coffee, which has a pronounced creamy taste due to the combination of sweet milk with whipped cream.

There are groups of special coffee drinks designed for people leading healthy lifestyle life, those who react negatively to caffeine, and for losing weight. These, for example, include Leovit products. These are drinks made from green coffee beans, enriched with vitamins and other functional components, which allow you to increase efficiency, improve lipid metabolism, prevent the accumulation of fats, and compensate for vitamin deficiencies. These are instant products packaged in sachets for one-time preparation of a drink.

Many well-known brands offer decaffeinated coffee to the market. This is both ground and instant coffee with a minimum alkaloid content in the composition. It is intended for people with hypertension and other categories of customers who, for a number of reasons, cannot consume a drink with properties that excite the nervous system.

Today, not all information about the composition of coffee beans is available to us due to its complexity and a long chain of transformations of some components into others during the processing of the product and its storage. But the information behind which the research of scientists stands speaks more about the greater benefits of the drink for a person than its harm. Although everyone who starts the day with a cup of coffee will never exchange its taste and aroma for another, even the most healthy drink!

The taste of coffee depends on the variety, quality, growing and processing conditions. coffee beans. On an industrial scale, 4 types of coffee are grown: Arabica, Robusta, Liberica and Excelsa. The most delicious and fragrant, and therefore the most expensive - Arabica. True, recently new varieties have appeared from the so-called "Ethiopian heritage" - wild-growing types of coffee. They are considered promising, but the best of them, such as Geisha, come from Arabica.

The fruits of the coffee tree are called berries (in the English tradition - cherries). In all types of coffee, the berries have the same structure and differ from each other only in size, thickness of the peel or parchment shell, and color.

The berry usually contains 2 grains. Ripe berries, depending on the type of coffee tree, turn red or yellow. As it matures, the pulp becomes more sweet taste. The pulp contains caffeine (although it is much less than in grains), it makes an invigorating drink - cascara.

The structure of the coffee berry:

1. The outer shell of the berry is the peel.
2. Under the peel is the pulp (pulp).
3. A layer of gluten separates the pulp from the shells of the grains. While the berries are green, this layer is hard, but as it ripens, it softens and becomes very sticky.
4. Under the gluten is a dense parchment shell.
5. The coffee bean is surrounded by a thin, silvery shell that flakes off when roasted.

The grain ripens together with the pulp, feeds on the useful substances takes on sweetness. Therefore, grains are valued only from ripe berries. If the berries are not ripe or overripe, the grains are classified as defective.

Peaberry (Peaberry coffee)

As a result of the mutation, up to 5% of coffee berries contain not two, but only one grain, called (peaberry in English - “pea”). Sometimes they mistakenly believe that it is two grains fused together. This is not so: when two grains grow together, you get a hollow ball that can be easily divided into two concave halves. Such grains are considered defective, the defect is called "elephant ears".

The formation process of the Peaberry is completely different. In a normal ovary there are always two tiny seeds. However, in mutated berries, the development of one grain stops, but the other grows significantly in size: after all, it gets all the nutrients that nature provided for two seeds.

Coffee brewed from peaberry has a brighter taste and an intense aroma. In Western Europe, the United States and Australia, gourmet cafes are opening, where coffee is prepared exclusively from peaberry.

It has been noted that most of the peaberry is formed on plantations where mineral fertilizers are not used. For example, in Tanzania, up to 10% of Arabica is peaberry. Taking advantage of the fact that unusual coffee is highly valued, Tanzanian farmers manually select the beans of the Peaberry and sell them for much more than ordinary Arabica.

In Latin America, the peaberry is called caracol (snail) or perla (pearl). Thanks to the use of modern technologies, 2-3 tons of coffee are harvested from one hectare (whereas in Tanzania - 300 kg). Therefore, Latin American farmers often do not see the point in manually sorting coffee to separate the Peaberry.

The chemical composition of coffee beans

Coffee beans contain over 100 chemical compounds. Many of them decompose during roasting, forming substances that affect the taste and aroma of coffee.

Substances affecting the properties of coffee as a drink:

• caffeine is an alkaloid that acts as an energy drink. Robusta has more caffeine than Arabica;
• trigonelline is an alkaloid that, when heated, is destroyed to form nicotinic acid. The decomposition products of trigonelline react, forming substances that create a pleasant aroma of roasted grains;
• carbohydrates, in particular, monosaccharides (glucose, fructose, lactose, sucrose), which give the drink a sweet aftertaste. In Arabica - 8.2-8.3% sugars, in Robusta - 3.3-4.1%. The brown color of roasted coffee beans is a consequence of caramelization of sugars during heat treatment;
• fats - when heated, they decompose, forming acids. It is precisely because of the presence of fats that roasted coffee at long-term storage acquires a rancid odor. It is believed that the least fat is found in Indian Arabica;
• organic acids: citric, tartaric, malic, oxalic, coffee. Fruit acids give the drink sourness: citrus or berry, sometimes with wine notes. If an unpleasant aftertaste of vinegar is felt in the drink, it means that the grains have undergone too long fermentation, which is why they have formed acetic acid. This taste is considered a disadvantage. Acids decompose when heated, so dark roasted coffee has almost no sourness. If you want to muffle the sourness in light roasted coffee, you need to prepare the drink in a pour over or brew using the cold brew method;
• chlorogenic acid (refers to organic acids), which in itself does not have a bitter aftertaste. When roasted, it forms chlorogenic acid lactones, which, in turn, decompose into phenylindanes - very bitter substances. Therefore, coffee from dark roast beans is always more bitter;
• tannins are compounds that give the drink a bitter-tart taste.

The dependence of the taste of coffee on climatic conditions

The taste of coffee of the same variety varies depending on the altitude at which the plantation is located:

• 600–1200 m - shades of earth and grass are sometimes felt in the taste, especially if the grains are processed in a dry way. With wet processing, the taste becomes more pleasant;
• 1200–1800 m - coffee has a nutty, citrus or vanilla-chocolate flavor;
• above 1800 m - floral, berry, fruit shades appear in the taste, sometimes - with wine sourness.

Alpine coffee is considered the best. However, harvesting is not easy: the plantations are located in places with difficult terrain, on the slopes of the mountains, where it is impossible to deliver equipment. Therefore, such coffee is harvested by hand and processed especially carefully, otherwise it will not be possible to sell it dearly.

Coffee bean sizes

To sort the grains, they are sifted through special sieves with cells of different sizes.

Types of coffee by the size of the beans (measured by green unroasted beans):

• very fine grain (sieve No. 12, cell side length – 4.764 mm);
• fine grain (No. 13, 5.161 mm);
• small grain (No. 14, 5.558 mm);
• medium grain (No. 15, 5.955 mm);
• good grain (No. 16, 6.352 mm);
• sufficiently large grain (sieve No. 17, 6.749 mm);
• large grain (No. 18, 7.146 mm);
• extra large grain (No. 19, 7.543 mm);
• very large grain (No. 20, more than 8 mm).

The size of the coffee bean does not directly affect the taste of the drink; no modern quality assessment system considers size as a criterion. Sorting is needed only for correct . The larger the grain, the more difficult it is to evenly fry it inside and out.

Defects in coffee beans

If the beans are not properly handled or stored in the wrong conditions, the drink will have an unpleasant taste and aroma. To determine the quality, 300 g of coffee is weighed and the number of beans with defects is counted.

Types of defects in coffee beans:

• black grains affected by a fungus (give an unpleasant taste to the drink);
• grains with holes damaged by insects;
• concave grains of irregular shape, resembling shells. As a rule, they have low acidity;
• oily grains. The defect occurs due to the low content of iron in the soil. The taste of the drink will be mild;
• Quakers are shriveled grains from unripe berries. Coffee is bitter, sourness is almost not felt;
• rust-colored grains obtained from overripe berries or subjected to too long fermentation. The drink has an acetic taste;
• broken, cut grains often smell bad;
• grains covered with mold;
• wrinkled yellow grains that have undergone too long drying;
• brittle (crystallized) grains of bluish-gray color. This appearance is acquired due to too high a drying temperature. Their coffee is tasteless.

Foreign inclusions are also considered defects: pebbles, leaves, coffee husks.

Why do we love coffee? The answer to this question is quite obvious - someone needs its invigorating effect, while others enjoy the taste and aroma. At the same time, few people think about what substances are contained in the grains from which it is made. The only thing known is caffeine, which wakes us up in the morning and helps us work during the day. However, this is not the only substance found in coffee beans.

The composition of this product is so rich that it is even surprising why the drink that is prepared from it can equally bring both benefit and harm. With the right approach, coffee can become not only an amazingly tasty energy drink, but also, to some extent, a cure for many diseases. Or at least help prevent them.

It’s worth mentioning right away that coffee beans do not have a stable composition. It depends on the variety, place of growth, time of collection and other important points. It also changes when - if raw materials contain several hundred chemical compounds, then in the finished product this figure can only reach two thousand. Surprisingly, despite all the progress that scientists have made in chemistry, it is still not possible to recreate at least something similar to natural grain. very far from what can be considered a real drink.

For the most part, they are composed of carbohydrates - they account for about half of the total mass. When roasting, the amount of some of them decreases, and sucrose turns into caramel. He is responsible for the brown color of the future coffee drink. Also, during the heat treatment, a substance such as caffeol is formed, which gives the specific aroma of coffee.

Another element on which the specific taste and aroma of the finished drink depends is trigonelline, which belongs to the group of alkaloids. It is he, and not caffeine, as we used to think, that is responsible for the flavor and aroma component. The latter also belongs to alkaloids and has a tonic property. Yes, in its pure form, caffeine has a bitter taste, but this does not affect the coffee drink in any way. The same substance can also be found in Coca-Cola - a couple of bottles are comparable in effect to a cup of natural coffee. The taste is completely different.

The taste of the future drink is also affected by such a chemical substance as tannin. First of all, it is responsible for the binding of polysaccharides and proteins. In green grains, the percentage of the substance is about seven percent. When roasted, it is destroyed, but this is what gives the grain a unique taste and aroma. It turns out that the destruction of tannin is a necessary condition for creating the coffee drink that we know and love.

Another important substance that is part of coffee is protein. Its amount is about 10% of the total amount of all substances.

talking about chemical composition grains, do not forget about vitamins and minerals, of which there are also a lot. What is really a lot here is vitamin B3. This substance affects the metabolism in the body. In addition to B3, coffee contains other important trace elements. Here are just a few of them:

• vitamins A, E, almost the entire group B, PP;
• iron;
• sodium;
• calcium;
• magnesium;
• zinc;
• copper.

As mentioned above, the chemical composition of grains can change under the influence of many conditions. But even the lowest grades of coffee beans contain many substances and their compounds. So we can safely say that a drink so beloved by many can be good for health, of course, if it is used correctly.

You should not drink coffee for those who have problems with the cardiovascular and nervous systems, gastritis, ulcers, diseases of the rectum.

In addition, excessive consumption of this invigorating drink can lead to insomnia, nervousness, and irritability. If you do not get carried away and take into account the state of your health, then coffee will not do any harm.

What can be said about instant drinks

Manufacturers are constantly working to improve the composition of instant coffee. But while it is very far from natural grain. In the best case, the substances that are present in coffee beans in powder will be no more than 20% of the total. Everything else is flavors, preservatives, dyes and other achievements of the chemical industry.

True, in stores, you can find instant coffee marked "organic". Such a powder will not contain any artificial additives, only coffee extract. Accordingly, the price of such a powder will be much higher. True, this guarantees only a natural composition, a pleasant taste and aroma.

But the chemical composition of an instant drink, even an organic one, is much poorer than that of its grain counterpart. Such valuable proteins, carbohydrates, amino acids and vitamins are here, if present, then in small quantities. What can not be taken away from instant coffee is the convenience of brewing and long. But, is it worth it to give up the pleasure of drinking a cup of fragrant tasty, and most importantly, natural drink?

photo: depositphotos.com/jirkaejc, Julia_Arda, muha04