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The article discusses the composition and physicochemical characteristics of the coffee drink, and describes the physiological effect of the coffee drink on the human body.

physical and chemical composition

drink coffee

influence on the body.

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Composition and physicochemical characteristics of coffee

For several centuries now, coffee, a drink with a charming taste, has been making people happy. What gives it its unique taste and aroma, invigorates and refreshes when consumed?

The coffee tree, like any other plant, through the root system receives from the soil a number of minerals necessary for normal development. These minerals make up the ash that remains after coffee beans are burned. The composition of ash in the form of various compounds includes: potassium, calcium, sodium, iron, sulfur, phosphorus, nitrogen, chlorine, magnesium and other elements. None of these elements are contraindicated for humans, but on the contrary, all of them in varying quantities are needed by humans for normal life. For example, iron is a component of hemoglobin in the blood, and sodium chloride is part of the liquid part of the blood - plasma. The normal rhythm of cardiac activity depends on the presence of sodium, potassium and calcium in the human body. Calcium and phosphorus are part of bone tissue. Sulfur and nitrogen are the basis of amino acids and proteins that make up the muscle and other soft tissues of the human body.

In 1819, the French scientist Runge isolated from coffee extract colorless silky crystals with a slightly bitter taste, the aqueous solution of which was many times superior to coffee decoction in its stimulating effect. This alkaloid substance was called caffeine. It took 80 years of hard work by scientists before the final composition of caffeine and its structural formula were established. Based on this formula, the German physicist E. Fischer obtained synthetic caffeine in 1897 and thereby proved the correctness of the structural formula.

It is interesting to remember that coffee was used as a remedy in classical Arab medicine in 900-1000 AD. “Bunchum” - under this name it was described by the ancient Arab scientist, physician and alchemist Abu Bahra Muhammad ibn Zahari Iina la Razi - known in history as Rizes. However, as the consumption of coffee as a drink increased, its medicinal properties began to be forgotten.

In the laboratory of I.I. Pavlov was the first to establish that caffeine enhances excitation processes in the cerebral cortex, eliminates drowsiness, facilitates the perception of the environment and increases performance. I.I. Pavlov concluded that long-term abuse of relatively large doses of caffeine can lead to functional depletion of brain cells.

After the discovery of caffeine, coffee experienced a renaissance as a remedy. Currently, caffeine is successfully used in medical practice for various diseases. It is part of many medications that help restore impaired functions of the human body. Therefore, taking a coffee drink containing caffeine is a kind of taking a very small dose of medicine and can thus be considered as a preventive measure that stimulates and maintains the functional activity of some vital human organs. In his research, I.I. Pavlov came to the conclusion that the degree of excitability from caffeine is individual and depends on the type of nervous system. With a weak type of nervous system, caffeine reduces arousal processes, so people of different temperaments react differently to an evening cup of coffee. For some it causes insomnia, for others, on the contrary, drowsiness. Another alkaloid found in coffee is trigonaline. It does not have stimulant properties, but plays an important role in the formation of the aroma and taste of roasted coffee.

The chemical composition of coffee is complex. Many chemical compounds were identified in it using chemical and chromatographic methods. Raw coffee contains: water, fats, proteins, mineral salts, the already mentioned water-soluble substances - caffeine, trigonaline, as well as chlorogenic acid, directly reduced (inert) sugar, sucrose, water-soluble proteins, water-soluble mineral salts, insoluble substances - helicellulose and cellulose. Commercial coffee contains 11% moisture, 11% fat, 13% proteins and other nitrogen-containing substances.

When roasting, the chemical composition of coffee changes, and its weight is also lost by 14-23%. Attitudes towards the degree of roasting of coffee vary. For example, in the USA they like light coffee, in Italy ~ dark, in France - medium-colored. The change in color indicates, first of all, the caramelization of sugars.

Coffee contains nitrogenous substances, lipids, carbohydrates, organic acids, oligoelements and vitamins.

Lipids. Coffee oil has a liquid consistency and contains glycerides of palmitic, stearic, caprionic and linolic acid. Fatty substances remain almost completely in the dry residue and do not pass into the finished drink; It also contains some phytosterol (coffee salt).

Carbohydrates. In roasted coffee, the soluble carbohydrate fraction - sucrose, glucose, fructose and galctose - is not very important and makes up approximately 28% of the total soluble components.

Organic acids. Coffee beans contain a lot of organic acids: pyruvic, oxolic, citric and malic.

Particular attention should be paid to chlorogenic acid. In raw coffee it is found as the double salt of caffeine and potassium. Chlorogenic acid is lost by 37-58% during roasting, and caffeine is released; 40% of caffeine remains in roasted coffee. The effect of chlorogenic acid has not yet been sufficiently studied.

Oligoelements and vitamins. The mineral content (Table 1) is of great interest: 100 ml of 5% coffee drink contains 136 mg of various mineral salts (Table 2).

Table 1

table 2

Amount of mineral salts in 120 ml of coffee drink (one cup) made from 6 g of coffee

1 g of coffee powder contains 0.29-0.32 mg of iron, 1.4-1.8 mg of phosphorus. Coffee also contains sulfur compounds - SO2, H2S, some vitamins (nicotinic acid, etc.), but they are of no practical importance.

Essential oils. They are formed during roasting of coffee and determine its specific aroma, contain terpenes (phenol products), and have an antiseptic effect.

Nitrogenous substances. Together with alkaloids - caffeine and trigoneline - coffee contains a certain amount of betaine, choline and amino acids - livcine, glutamic and aspartic acids.

In green beans, caffeine is found in the double salt (potassium caffeine salt of chlorogenic acid). At the time of roasting, it disintegrates and partly sublimates, which is explained by the loss during this process. The caffeine content depends on the type of coffee (Table 3).

Table 3

The data given in table. 3 indicate that the degree of caffeine content depends on the geographical origin of the plant. Species with the highest caffeine content grow in West and Central Africa, with less in East Africa; It is not found in coffee from the Malagasy region. The Brazilian variety "Santos-5989" - type 2 contains 1.066% caffeine in raw form, and 1.099% in roasted form. In Arabic coffee - 0.3-2.5%, in Robusta - from 1.97 to 2.6%, in Liberica - from 1.08 to 1.53%.

The given data on the composition of coffee does not give an idea of ​​the full variety of substances contained in it. They provide only general information about some of its main substances.

The composition of raw coffee beans used for the production of various coffee products includes: water 10-13% (after roasting: 1-2.5%); protein substances 11%; fats 10-13%; carbohydrates 30-40%; alkaloids (caffeine) 0.8-2.5%, depending on the variety; mineral and organic substances 4% (90% of which remain in the final product); extractives 0.1% volatile aromatic substances (formed during the roasting process); lipids; phenolic compounds; vitamins; enzymes, etc. Acids 30-70% disintegrate during the roasting process. Coffee beans contain about 1,300 different substances, and not all of them are known to science. The composition may vary depending on the variety, region of cultivation and roasting. The roasting process produces up to 800 different flavors. In other words, to create the unique aroma of coffee, 800 individual elements are needed. Unlike all other flavors, coffee flavor cannot be synthesized.

Water. The moisture content of raw coffee is essential for assessing its quality.

Raw coffee beans belong to the group of products that have a capillary-porous colloidal structure (Fig. 1). They are characterized by various forms of connection between water and the material (free, bound and tightly bound). The water content of raw coffee beans according to the standard adopted by the International Coffee Organization (IOC) should be 12±1%. However, depending on storage and transportation conditions, the moisture content of raw coffee ranges from 9-14%.

Rice. 1. Ripe coffee beans

As studies conducted by F.G. have shown. Nakhmedov et al. (1982), raw coffee Santos I grade, Robusta I grade and Robusta II grade, received in 1975-1976, are significantly different in moisture content from the same varieties received in 1979-1980. Moreover, the same type of coffee came from the same supplier country at different times of different quality. A significant difference was found in the moisture content of Robusta II grade coffee beans from Angola, Brazil, India, and Ethiopia.

According to Doroshevich (1978), the rate of sorption and desorption of water vapor by coffee beans is relatively high. Coffee beans absorb moisture especially intensively at high relative air humidity and elevated storage temperatures. At a relative air humidity of 40-60%, the moisture content in the grains does not exceed 12%; at air humidity of 63-65%, raw coffee retains its normal color, freshness and taste throughout the year; at an air humidity of 65-70%, the beans turn yellow and then turn white; at 70-75%, along with the yellow color, the characteristic smell and taste of stale coffee appears. When relative air humidity exceeds 75%, coffee acquires a moldy smell and taste and becomes practically unfit for consumption.

However, Punnett (1959) showed that at a relative air humidity of 95% and a temperature of 20-26 ° C, raw coffee beans reach equilibrium moisture content after 25-30 days, while roasted coffee after 5-7 days, and instant coffee after a few hours.

Raw coffee is a biological object, and the water it contains undoubtedly plays an active role in the biochemical and physicochemical processes occurring in the cells and tissues of the beans.

Extractive substances. The content of water-soluble extractive substances in different types and varieties of raw coffee varies and is approximately 20-29%. The smallest amount (19-20%) is contained in the highest grades of Arabica coffee, followed in an increasing degree by the first varieties of the Arabica type (21-23%), the first varieties of the Canifora (Robusta) type (24-27%), the second varieties of the type Rosin (27-29%). Sometimes in some varieties of that and. In other types, the content of extractive substances goes beyond these limits. Most often this is due to weather conditions and methods of primary grain processing.

The extractive substances of raw coffee include alkaloids, proteins, phenolic compounds, mono- and disaccharides, lipids, organic acids, amino acids, mineral elements and some other substances contained in small quantities.

Alkaloids. In coffee beans, alkaloids are represented by methylated purine derivatives: caffeine, theobromine and theophylline (Chichibabin A.E., 1958; Kretovich V.L., 1971; Clifford, 1975), as well as trigonelline.

Caffeine (C8H10N4O2) is the most important alkaloid in coffee beans and is known as 2,6-dioxy-1,3,7-trimethylpurine, or 1,3,7-trimethylxanthine (Fig. 2).

Rice. 2. Caffeine

Caffeine is a colorless and odorless substance; in an aqueous solution it gives a bitter taste. Caffeine crystallizes from aqueous solutions in the form of crystalline hydrate, which has the shape of long, fragile, silky needles. Anhydrous caffeine melts at 236.5°C and can sublimate when heated carefully. It is readily soluble in chloroform, methylene chloride, dichlorethylene and trichlorethylene. Aqueous solutions of caffeine have a neutral reaction; it forms salts with acids. Caffeine in raw coffee is in a free state bound with potassium chlorogen (Kolesnik, 1962; Goldoni, 1979).

Different types of coffee are characterized by the following caffeine content (in terms of dry matter, in%); Arabian 0.6-1.2; Robusta 1.8-3.0; Liberian 1.2-1.5.

Trigonelline (C7H7O2N), or methyl betaine nicotinic acid, is formed in plants by methylation of nicotinic acid (Fig. 3).

Nicotinic acid Trigonelline

Rice. 4. Theobromine Monomethylalloxane Monomethylurea

Trigonelline is found in relatively large quantities in Arabica coffee varieties (1.0-1.2%). In coffee varieties of the Canifora (Robusta) type there is slightly less of it (0.6-0.74%), and in varieties of the Liberica type it is only 0.2-0.3%. Trigonelline is highly soluble in water, but is thermally unstable. When processing coffee beans, it is easily converted into nicotinic acid, and therefore trigonelline is considered the main precursor for the formation of nicotinic acid (vitamin PP) in coffee beans.

The presence of nicotinic acid in raw coffee beans was shown as early as 1945 (Tiplay, Kriegl and Ilwage). It was found that the content of the water-soluble fraction of nicotinic acid in raw coffee beans is significantly less (1.3 mg%) than in alkaline-soluble ones (in 1 N NaOH solution 6.6, in 5 N NaOH solution 9.5 mg% ).

Theobromine (C7H802N4) is a 3,7-dimethylxanthine, since upon oxidation it forms monomethylalloxane and monomethylurea (Chichibabin, 1958) (Fig. 4).

It is a colorless, finely crystalline powder, sparingly soluble in water. Theobromine melts at 351°C, is capable of sublimation, and easily dissolves in caustic alkalis, giving, for example, sodium salt. The theobromine content in raw coffee beans is insignificant - 1.5-2.5 mg% (Clifford and White, 1976).

Theophylline (C7H8O2N4) is a 1,3-dimethylxanthue that forms colorless silky needles containing one molecule of water of crystallization. Theophylline is sparingly soluble in cold water and melts at 269-272°C. The total amount of it in beans of wild coffee plants is 1.0-4.0 mg% (Fig. 5).

Rice. 5. Theophylline

From the groups of plant substances of secondary origin, the glucoside mascaroside (C26H36O11) was discovered and isolated in crystalline form in the beans of wild coffee plants (C. vianneyi). It has been established that it is a pentacyclic digerpene glucoside, similar in some properties to cafamarin, found in coffee beans (C. Buxifolia). No cafamarin was found in C. vianneyi coffee beans. In addition, two other substances close to mascaroside were isolated from the grains of C. vianneyi (Hammonaya et al., 1975); Gerhard and Helga, 1978), using chromatography and photometry methods, established that the beans of Robusta and Arabusta coffee contain diterpene glucoside in the form of traces, while in Arabica coffee it is 170 - 460 mg/kg. Another diterpene glucoside is contained in raw Robusta coffee beans in an amount of 10-45 mg/kg, in Arabusta coffee beans - 60 and Arabica - 290-340 mg/kg.

From raw coffee beans, polyamines, putrescine, spermine, spermidine were isolated and identified by thin layer chromatography (Eimorim G. and Eimorim V., 1977), which form various heterocyclic alkaloids upon deamination or oxidation.

Protein substances. For the first time, relatively in-depth studies of the protein substances of coffee were carried out by Underwood and Ditridge in 1952. The authors, having hydrolyzed the proteins of raw coffee, isolated 14 amino acids and quantified 9 components from them. G. Theiler (1977) published a series of articles showing that raw coffee of the three main varieties (Arabica, Robusta and Liberica) contains almost equal amounts of protein (amine nitrogen 1.55-1.63%, total protein content 9.69-10.19%).

The amino acid composition of raw coffee was studied using liquid ion exchange chromatography on LKB-4101 (Sweden) and Hitachi (Japan) analyzers. To determine free amino acids, a 100 g sample of the test material was ground in a mortar with distilled water, quantitatively transferred into a 100 ml volumetric flask, extracted for 1 hour, the sediment was decanted, refilled with water and extracted twice more. The combined extracts were evaporated at 40°C until water was completely removed, the sediment in the flask was dissolved in 10 ml of citrate buffer solution with pH 2.2. 1 ml of this solution was applied to the resin of the amino acid analyzer. The quantitative composition of amino acids was determined by comparing the peak areas in the chromatogram of the studied samples, as well as the peak areas of the calibration mixture of amino acids (Table 4).

Table 4

Amino acid composition of raw Mexican Arabica coffee

	Available amino acids, dry matter	Bound in proteins amino acids, g/100 g dry matter
Aspartic
Glutamic
Methionine
Isoleucine
Phenylalanine
Histidine

To determine the amino acids bound in proteins, acid hydrolysis of protein substances was first carried out in 6 N. HC1 at 105°C for 24 hours. Then the protein hydrolyzate was evaporated until hydrochloric acid completely volatilized, the precipitate was dissolved in a citrate buffer solution with pH 2.2, filtered and used for testing on an amino acid analyzer.

γ-aminobutyric acid was found in coffee beans from Vietnam, and Pereira and co-workers (1978) found pipecolic acid in raw Arabica and Arabica-Robusta hybrid coffee beans from Angola, which was not found in raw coffee from other varieties. These researchers separated and identified coffee amino acids using electrophoresis and thin layer chromatography.

According to. G. Theiler and Geigl, Liberica coffee beans do not differ in amino acid composition from coffee beans of other varieties.

In general, it has been established that the amino acid composition of Arabica, Canifora and Liberica coffee is almost the same, but their content differs markedly from each other, which is explained by the growing conditions.

Lipids. Coffee belongs to the group of plant materials rich in lipids. Arabica coffee contains 12-18% lipids, Canifora (Robusta) coffee - 9-13.4% and Liberica coffee - 11-12%. The general properties of lipids are largely determined by the fatty acids they contain. Gas chromatographic analysis revealed that unsaturated fatty acids account for 50.1-59.9% of the total fatty acids in raw coffee. A high content of unsaturated fatty acids may indicate possible oxidative processes in coffee oil. However, long-term observations of changes in peroxide and thiobarbituric numbers of fat during coffee storage indicate no changes in these indicators.

The content of free fatty acids in raw coffee beans of the highest grades is 0.5-3%, while in beans of lower quality it is up to 20%. Based on the amount of individual fatty acids between varieties of the same type of coffee, differences in the distribution of fatty acids between triglycerides, diterpene esters and esters themselves have been identified (Wurziger, 1973). Of the total fatty acids in coffee essential oils, linoleic acid makes up 37-50%, palmitic acid - 23-25%, oleic acid - 9-14%, linoleic acid - 1-5%, arachidonic acid - 1-4%, and myristic and behenic acid - up to 0.6%. Along with these, gadoleic, lignoceric, margaric and hexadienic acids were also found in traces.

The composition of fatty acids in coffee beans of the wild species C. Racemosa is somewhat different. They are dominated by palmitic (39.1%), linoleic (34.71%), stearic (10.41%) and oleic (10%) acids.

The iodine number of raw coffee bean oil is 82-102, the saponification number is 180-189, the benzidine number is 0.9-1.1, the refractive index is 1.4700-1.4744. Coffee oil contains approximately 4% phosphatides.

The unsaponifiable fraction of lipids contains components that are insoluble in water after their treatment with an alcoholic alkali solution. The oil of Arabica and Canifora (Robusta) coffee beans contains from 7 to 20% of unsaponifiable lipid components, which determine the low melting point of the oil (8°C), and by removing them, the melting point can be increased to 34-36°C.

Two diterpenes - cafestrol and caveol (1,2-dehydrocafestrol) - make up 40 and 20% of the unsaponifiable fraction, respectively, and are present in coffee oil mainly in the form of fatty acid esters. Contains 1-5-abiene-13, 19-diol and atractyloside in smaller quantities.

Coffee oil sterols make up about 20% of the unsaponifiable components of lipids, serotonins make up 3-6%, and the rest (~15%) comes from aliphatic hydrocarbons, including nanoxane and various pigments.

Recently, thanks to new methods of structural analysis, some success has been achieved in the identification of some sterols. It has now been found that coffee oil sterols are similar to those found in other types of plant materials. These are mainly sigo-shrin (53-55%), campestrol (16-18%), stigmasterol (22-28%) and about 10 more sterols that are present in smaller quantities and make up approximately 7% of all sterols in coffee oil.

The cuticular layer of raw coffee beans contains carboxylic acid hydroxytryptamides (5-hydroxytryptamides) in amounts ranging from 0.08 to 0.24%. Along with the antioxidant properties, hydroxytryptamides of carboxylic acids play the role of a factor in the freshness or aging of coffee, since during storage, simultaneously with the color change of coffee beans (darkening) under the influence of light and air, the content of tryptamides in them also decreases (Wurziger, 1973). Due to the fact that hydroxytryptamides cause gastric dysfunction in people with hypersensitivity, a number of methods have been developed to remove them from coffee beans.

Carbohydrates. They make up 50-60% of the total mass of raw coffee beans. Coffee carbohydrates include sucrose (6-10%), cellulose (5-12%), pentose (3-5%), pectin (2-3%) and high molecular weight polysaccharides (fiber, lignin, etc.). It has been established that the main water-soluble component of high-molecular polysaccharides of raw coffee is arabinogalactan (2-5%).

In addition, glucogalactomannan, galactose, minnose and arabinose have been isolated from coffee beans. For a long time it was believed that raw coffee lacks free monosaccharides (glucose and fructose), but research has found that sucrose predominates in Arabica coffee, and reducing sugars predominate in Canifora (Robusta) coffee beans. This was confirmed in the works of Lerici, Peipi and Matssa (1978), who, using gas-liquid chromatography in 80% aqueous solutions of ethyl alcohol of raw Arabica coffee beans from Ethiopia and Brazil, along with sucrose, detected and quantified fructose, α-glucose, β-glucose and two sugars were not identified. In general, the total amount of reducing sugars in grains reaches 0.7-1%.

Phenolic compounds. These coffee compounds are represented by tannins (tannin, catechins, etc.) and chlorogenic acids. The main part of phenolic compounds are chlorogenic acids. This concept was first introduced by Payen in 1846 to explain a component he discovered in coffee beans.

Chlorogenic acid was first isolated in crystalline form from coffee beans by Gorter in 1908, and its structure as caffeoyl-3-quinic acid was established by Fischer and Dangshet in 1932.

Chlorogenic acids include about ten compounds found in coffee, and similar compounds are found in other plants.

In the old literature, information about this group of substances is very vague, since several chlorogenic acids were often considered as one compound. The situation was aggravated by the different nomenclature of chlorogenic acids and the use of trivial names. Only in recent years, thanks to the use of modern analytical methods and processes for the isolation and separation of this group of compounds, has it been possible to accurately establish their structure and partially elucidate their physiological action.

Below are the trivial names of chlorogenic acids and their corresponding names according to chemical nomenclature (Clifford and Byte, 1976; Goldoni, 1979) (Table 5).

Table 5

Trivial names of chlorogenic acids and their corresponding names according to chemical nomenclature

Chlorogenic acids are mono- or diesters of cinnamic and quinic acids. Esters of quinic acid with caffeic and ferulic acids were also found in coffee beans.

Chlorogenic acid (capheyl-3-quinic acid)

Neochlorogenic acid (capheyl-5-quinic acid)

Cryptochlorogenic acid (capheyl-4-quinic acid)

Isochlorogenic acid is actually a mixture of dicaffeylquinic acid. It was initially identified as caffeoyl-5-quinic acid (1950), then as caffeoyl-4-quinic acid (1955), and finally in 1964, isochlorogenic acid was found to consist mainly of three fractions dicaffeylquinic acid and exists in the form of its isomers.

Raw coffee beans contain approximately 7-10% chlorogenic acids. In coffee of the type Canifora (Robusta), their concentration is higher (9-11%) than in coffee of the Arabica type (5.5-8.0%). The main share of chlorogenic acids consists of caffeylquinic acids (chlorogenic and neochlorogenic acids). So, in Arabica coffee there is 5.5-7.0%, in Kinifora coffee there is 8.0-9.0%. This is followed by dicaffeylquinic acids (isochlorogenic acids). In Arabica coffee there is 0.5-0.6%, in Canifora coffee it is 1.4-1.7%. Coffee contains feruloylquinic acid in smaller quantities: Arabica coffee contains 0.2-0.25%, and Canifora coffee contains 0.6-1.2%. In some typical coffee varieties most widely used for industrial processing, the following content of chlorogenic acids was determined by gas chromatography and thin layer chromatography (Table 6).

Table 6

Research conducted at the All-Union Scientific Research Institute of Food Concentrate Industry and Special Food Technology (VNIPP and SPT) using the colorimetric method has established that the content of tannins in Arabica coffee (India) is 6.1-6.36%, in Canifora coffee Robusta I grade (India) - 6.8-7.7%, in Santos coffee I grade (Brazil) - 3.6-4.6%.

Minerals. Raw coffee beans contain 3-4.5% minerals. The composition and content of the main elements have been established for a long time. However, it was not until 1972 that Tserevitinov et al. used atomic absorption spectrophotometry. (1972) managed to determine a more complete quantitative composition of minerals in coffee beans (in mg%): potassium 1712-1750, magnesium 142-176, calcium 76-120, shirium 2.3-17, iron 2.1-10.0 , manganese 1.1-9.8, rubidium 0.6-4, tsnik 0.5-3.2, copper 0.6-2.3 and strontium 0.4-1.3, as well as traces of chromium, vanadium , barium, nickel, cobalt, lead, molybdenum, titanium and cadmium.

According to the literature, there is no definite relationship between the amount of minerals and the quality of the coffee drink. However, it is believed that the content of zinc, manganese and rubidium in raw coffee beans is responsible for the best properties of the drink.

Organic acids. Citric, malic, maleic, acetic and oxalic acids have been found in raw coffee beans (Sivec and Foote, 1963). In coffee beans of different types and varieties (Arabica of the highest grade from Colombia, Santos of the first grade from Brazil, Robusta of the II grade from Indonesia, etc.), the composition and content of organic acids are different. It has been shown that the acidity of raw coffee of various botanical species and varieties ranges from 2.4 to 4.0°T. During long-term (3-5 years) storage of raw coffee under normal conditions, its acidity increases slightly.

Vitamins. Thiamine (B1), riboflavin (B2), pantothenic acid, nicotinic acid (PP), pyridoxine (B6), vitamin B12 (Chinenova, 1970) and tocopherol (E) were found in coffee beans (Folstar, Von der Plas, Pilnik and Heus , 1977).

Enzymes. Raw coffee supplied for industrial processing is a biologically active product in which enzyme systems of almost all classes are localized: oxidoreductases, hydrolases, transferases and isomerases, which play an important role in the biochemical and physicochemical processes of grain.

The change in color of raw coffee of different types and varieties from green and light green to white, whitish-yellow, yellow and dark brown is associated with a change in the activity of a complex of enzyme systems contained in coffee beans.

All substances included in the chemical composition of coffee are volatile and are quickly oxidized by oxygen; therefore, it is recommended to either roast coffee immediately before consumption, or store roasted coffee for a short time in hermetically sealed glass or tin jars. The amount of soluble substances transferred into the drink reaches 30%, which is approximately 85% of the total amount contained in roasted coffee beans. In this case, up to 80% of chlorogenic acid and up to 90% of caffeine are transferred into the drink.

Physiological effect of coffee on the human body

Coffee evokes a variety of feelings in relation to its taste - from hostility to delight, but does not leave anyone indifferent. Its strong influence on the human body has given rise to these diametrically opposed opinions about its harm and benefits.

An example of heated debate on this issue is a story that occurred in the 18th century in Sweden. To resolve this dispute, King Gustav III decided to do the following - he replaced the death penalty for two twin brothers with life imprisonment. They had to live in equally prosperous conditions and drink a large portion every day: one of tea, the other of coffee. The convicts were imprisoned in a fortress and two professors had to watch them. Years and decades passed. The king died, the professors died, but the brothers still lived and felt cheerful. Finally, at the age of 83, the convict who drank tea died, and a few years later the one who drank coffee died.

The debate about the dangers and benefits of coffee continues today. Many theoretical works, scientific studies, and clinical experiments are devoted to this issue. But most research works are devoted to the effect of pure caffeine on the human body. It should be noted that the effects of coffee and caffeine are different and depend on the degree of their concentration, different methods of intake and the presence of related substances in coffee. However, there is also a similarity in their influence.

What is the effect of coffee on the human body?

Coffee is an stimulating drink, and it is this quality that makes it widely popular. Coffee has an exciting and stimulating effect on a person during physical fatigue, giving vigor and strength for a short time. Coffee has an effect on the higher parts of the central nervous system. Caffeine is one of the main plant alkaloids, stimulates and normalizes the functioning of the central nervous system. Physiologically, it is a tonic: it eliminates lethargy, drowsiness, improves the functioning of the sensory organs, and accelerates the transmission of nervous excitement. Caffeine is especially useful for people with mental work, stimulating nerve cells, it increases their receptivity, and encourages focused thinking.

What is coffee tolerance in a healthy person? A cup of coffee typically contains 100 mg of caffeine in the Arabica variety and approximately 250 mg in the Robusta variety. Therefore, for many people, coffee causes palpitations, irregular pulses, heart pain, increased nervous excitability, insomnia, and for some, paradoxically, drowsiness. A cup of coffee prevents a decrease in activity after eating and stimulates a person’s physical and mental activity.

Coffee has a certain effect on the digestive organs. It causes an increase in the secretion of gastric juice and hydrochloric acid. 20-30 minutes after drinking black coffee, the acidity in the stomach reaches its maximum. An increase in the concentration of the drink in the stomach contents also increases the content of free hydrochloric acid, and the total acidity increases. Gastric secretion caused by coffee is equivalent to the action of the universally recognized activator of the secretory reaction - meat broth. Coffee helps increase the digestibility of food. It is not for nothing that many peoples traditionally serve black coffee after breakfast and lunch.

As a strong stimulant of gastric secretion, black coffee should be excluded from the diet of patients with peptic ulcers and gastritis; in this case, it can be recommended to drink coffee with milk and cream, while its effect on gastric secretion is significantly reduced. Coffee stimulates intestinal motility.

It is interesting to note the effect that coffee has on the gallbladder, bile ducts and liver. Coffee increases the secretion of bile. Caffeine stimulates the metabolism of certain substances in the body and normalizes the absorption of sugar and inhibits the activity of the thyroid gland. Coffee inhibits the vital activity of microorganisms and, therefore, from this point of view, it is useful for humans in many cases.

In recent years, the medical literature has provided many examples of the harmful effects of coffee, causing various diseases, including: myocardial infarction, early atherosclerosis, cancer of the digestive system, bladder cancer, diabetes, hypertension, padagra, kidney disease, etc. A quick review of the latest research in connection with the effect of coffee on the human body indicates that coffee is one of the few stimulants that do not have significant side effects on the cardiovascular system, fat metabolism, carbohydrates, uric acid, as well as on the activity of the liver and stomach and excretory system.

Coffee, like alcohol, excites, warms and activates human activity, but with the difference that it does not have an intoxicating and relaxing effect and does not lead to the consequences that arise as a result of drinking alcoholic beverages.

However, coffee consumption in the world has been declining recently. One of the reasons for this decline is that doctors attribute carcinogenic properties to it; doctors also do not recommend drinking coffee due to its high caffeine content. They say that coffee has a harmful effect on the circulatory system, cardiac activity, and sleep. Of course, with all its positive qualities and physiological properties that led to its widespread use, coffee can also have harmful effects on the body. It is contraindicated for hypertension, insomnia, increased excitability of the nervous system and other diseases.

Intoxication is also dangerous, i.e. poisoning with large amounts of caffeine due to coffee abuse.

So to drink or not to drink coffee? Is it harmful to health? These questions remain open. True, in addition to caffeine, coffee contains about 300 organic substances, the effects of which have not yet been studied. It is known that caffeine penetrates into all parts of the body within 5 minutes after consumption, causes a narrowing of some blood vessels and dilation of others, increases the metabolic rate, accelerates the production of stomach acids, facilitates the perception of sensory stimuli, activates brain activity, has a beneficial effect on respiratory function and etc. Caffeine is eliminated from the body the next day. In clinical practice, the therapeutic dose of caffeine is 0.25 g, the maximum is 1.5 g per day, and the lethal dose is 10.0 g, i.e. 100 cups of coffee.

Japanese doctors discovered healing properties in coffee. They believe that the drink helps in the fight against atherosclerosis, as it increases the content of benign cholesterol in the blood, which prevents the hardening of the walls of blood vessels. To confirm these findings, an experiment was conducted at the Jikyai Medical Institute in Tokyo. Volunteers drank 5 cups of black coffee daily for 4 weeks. Three of them “left the race” because they began to complain of disgust for the drink. For the rest, after 4 weeks, the content of benign cholesterol in the blood increased by an average of 15%; after the experiment was stopped, the cholesterol content began to decrease.

Based on studies on the harmfulness of coffee, scientists believe that moderate consumption does not pose a serious danger. For a healthy person, coffee provides nothing but benefits, of course, if it is not abused, like any other food. Contraindications for drinking coffee are relatively limited.

How many cups of coffee can you drink a day without risking your health? If it is “robusta”, then it is reasonable to stick to the norm of 1-2 cups of coffee per day, “Arabica” - 3-4 cups. The nutritional value of coffee is relatively small: a cup of coffee without sugar provides approximately 11 calories, with the addition of milk and sugar - about 78 calories.

Coffee beans contain about 1,300 different substances, and not all of them are known to science. The composition may vary depending on the variety, region of cultivation and roasting. The roasting process produces up to 800 different flavors. In other words, to create the unique aroma of coffee, 800 individual elements are needed. Unlike all other flavors, coffee flavor cannot be synthesized. The composition contains: carbohydrates - 30-40%; water - 10-13% (after roasting: 1-2.5%); proteins - 11%; fats: 10-13%; minerals - 4% (90% of which remain in the final product); acids - 30-70% disintegrate during the roasting process; alkaloids (caffeine) - 0.8-2.5%, depending on the variety; aromatics - 0.1% volatile aromatics (formed during the roasting process).

It is important to understand about science in general and especially about biology: it does not have ready-made and clearly formulated answers, especially when it comes to our body and the substances that we use; no scientist can tell you: don’t eat this, sleep just this much, don’t drink coffee and everything will be fine. Complex systems simply don't work that way. Coffee is even funnier: it is the most popular psychoactive drug (in the original sense of the word - an addictive substance) in the world, millions of people drink it every day, and scientists are constantly conducting research proving that it is either the most wonderful or the most terrible drink in the world.

Drinking coffee represents a truly rare case of combining business with pleasure. Coffee has great advantages over other drinks in terms of the content of substances beneficial to health. But if drinking coffee leads to discomfort in the chest, then it would be better to give it up.

Bibliographic link

Pendzhiev A.M. PHYSICAL AND CHEMICAL COMPOSITION OF COFFEE DRINK // Rational nutrition, food additives and biostimulants. – 2016. – No. 1. – P. 100-111;
URL: http://journal-nutrition.ru/ru/article/view?id=35722 (access date: 02/14/2020). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"

Coffee contains a huge number of different substances. Among products of natural origin, coffee beans remain the record holders in terms of the number of constituent components. They contain not only organic, but also inorganic components. It is thanks to this diversity that this popular drink is able to have such a powerful effect on the human body. It is curious that it affects almost all organs and tissues. When you drink another cup of aromatic coffee, its composition directly affects the reaction of your body. This is why it is so important to know what coffee beans are made of and what happens to these substances during roasting. Let us warn you right away that the chemical composition of coffee is very complex and confusing. According to the most conservative estimates of scientists, coffee contains about 1200 substances. We will take a detailed look at the composition of coffee beans, their nutritional value, as well as their effect on the human body.

Coffee: chemical composition

After you drink a cup of coffee, the chemical composition of this product directly affects how you feel. It is curious that scientists have calculated about 1,200 different components in coffee. The effect of many of them on our body has been practically unstudied. The majority are aromatic substances. It is thanks to these volatile compounds that coffee captivates us with its amazing aroma. They also directly affect the taste that the drink acquires. Since the taste of coffee depends specifically on volatile compounds, it is so important to store coffee beans and ground coffee in tightly closed, airtight containers or special bags. The main enemy of coffee is oxygen. Under its influence, coffee components quickly oxidize and also volatilize.

The composition of coffee is complex. It has not yet been fully studied. But its main components are well known. The most important among them is caffeine. The concentration of other substances will directly depend on the type of coffee and the soil on which it grew. By the way, many substances appear during roasting of grains. About 80% of them are responsible for the taste of the final drink. Coffee consists of:

• alkaloids;
• phenolic compounds;
• proteins;
• sugars and polysaccharides;
• organic acids;
• lipids;
• minerals;
• amino acids, etc.

Different types of coffee contain approximately the same amount of protein – 9-10%.

Carbohydrates make up about 50-60% of the total mass of coffee. They include cellulose, sucrose, pectin and polysaccharides. Among them, the polysaccharide with the difficult name arabinogalactan dissolves best in water. Its share is 2-5% of the total mass of coffee beans. It was previously believed that raw coffee did not contain monosaccharides, in particular glucose and fructose. But now there are already research results in which sucrose was discovered in Arabica. But fructose and glucose are also found in Brazilian coffee. But when beans are roasted, the carbohydrate complex changes significantly. For example, sucrose practically disappears. But monosaccharides, although they decrease in quantity at the initial stages of roasting, are restored at the end of it. Some of them are consumed during caramelization of coffee beans during roasting.

Caffeine

Caffeine is the main active ingredient in coffee. Thanks to its effects, our body is charged with vigor, vascular tone increases, and the functioning of the brain, gastrointestinal tract and other systems improves. It is not for nothing that caffeine was included in the list of medicinal substances. It has long been used in some medicines. The most famous of them is Citramon.

Caffeine is the most important alkaloid found in coffee beans. It has no color or smell. In aqueous solution it has a bitter taste. Different types of coffee contain different amounts of caffeine. The quality characteristics of the raw material directly depend on its concentration. The more it is, the more coffee beans are valued.

Why does caffeine affect our body so much? It is an alkaloid that can stimulate the central nervous system. It is this ability that ensures such a violent reaction of the human body to drinks with a high caffeine content. It is interesting that caffeine was first obtained from coffee beans. That is why this substance was called caffeine. It is this powerful alkaloid that provides the tonic effect of coffee. However, this drink not only tones, but also increases performance, physical and mental. To ensure this energizing effect, coffee producers strictly monitor the caffeine levels in the beans they use. The norm is no less than 0.7%. It is this alkaloid content that ensures the sustained tonic effect of coffee.

What determines the final level of caffeine content in coffee beans? First of all, the degree of ripening of the grains plays a role. The better they ripen, the more caffeine they accumulate. Roasting the beans also plays an important role. The more they are roasted, the greater the caffeine concentration. If the recommended concentration is maintained, then a teaspoon of ground coffee contains about 0.1 - 0.2 g. caffeine in its pure form. This amount will be quite enough to get a pronounced tonic effect. But doctors do not recommend increasing this dose. Otherwise, you may get a negative response from the body to an overdose of caffeine. The maximum dose you can afford is a concentration of 0.3 g. caffeine in one go. After this, you should completely abstain from drinking coffee for 3-4 hours.

What happens if a person exceeds the dose of caffeine? Regularly exceeding the dose of caffeine recommended by doctors can lead to the following negative consequences:

1. the work of the heart will increase;
2. excitability will increase;
3. sleep may be disturbed, etc.

Trigonelline

Coffee contains several alkaloids. One of them is trigonelline. Most of it is found in Arabica. But in Robusta and Liberica varieties there is a little less of it. Without heat treatment, this alkaloid is completely tasteless and odorless. It is highly soluble in water, but is unstable when exposed to high temperatures. When the grains are roasted, it is transformed into another substance - pyridine. It has a pronounced specific aroma. Trigonelline can interact closely with nicotinic acid. This is vitamin B3. When heated, the nicotinic acid molecule contained in trigonelline is released. This is why there is a consistently high level of vitamin B3 in coffee. By the way, our body really needs it. It is thanks to nicotinic acid that we have an active metabolism. It also helps our nervous system function properly. If there is a deficiency of vitamin B3 in the body, the nervous system immediately suffers and metabolism deteriorates. This also threatens the development of such a terrible disease as pellagra.

Coffee beans contain more than just vitamin B3. There are other vitamins in this group. Each of them is extremely important for our body to function properly. It is curious that after heat treatment of the grains occurs, a whole spectrum of B vitamins is immediately formed in them. Also in this aromatic drink, a fairly high concentration of vitamins A, D, E was found. Each of them has its own important function:

• Vitamin A ensures the growth and development of the body.
• D helps to better absorb phosphorus and calcium in our intestines.
• Vitamin E is a natural stimulant of our immune system and helps renew our cells. This is the vitamin of youth.

It is very important that coffee contains many essential organic compounds. These are acids and essential proteins. For our cells they are a source of energy and continuous nutrition. Without them, it is impossible to renew our tissues and organs, as well as the functioning of the body as a whole. By the way, coffee has become that unique plant product that contains the most important amino acids. Our body mainly receives them from fish or meat. Our body is not able to synthesize these amino acids on its own, which is why it is so important that it regularly receives them from the outside. Without amino acids, the process of cell restoration will simply be impossible. But this is extremely important for our organs and tissues. If the body does not regularly produce new cells, the body will simply begin to age. Without this, internal organs will also not be able to function normally, and immune defense will not work.

Tannin

Raw grains contain quite a lot of tannin - 4-7%. But after roasting, its concentration decreases. Only about 1% or less remains in the finished grains. Tannin is highly susceptible to oxidation. Already under the influence of 80 degrees, its transformation begins. By the way, it is due to the oxidation of tannin that coffee beans acquire a pleasant brown tint during roasting. It is formed by dark pigments resulting from the oxidation of tannin. Scientists don't think so. That the destruction of tannin negatively affects the characteristics of coffee. On the contrary, it is this process that leads to the fact that coffee acquires its characteristic taste and shade. But if the grains are heated too much, the tannin will completely decompose. This is why some coffee beans give off an unexpressed, empty taste later. This means that the beans were not roasted correctly and the tannin was completely destroyed.

Chlorogenic acids

The main part of the phenolic compounds in coffee consists of chlorogenic acids. These are esters of two acids - quinic and cinnamic. Scientists also discovered esters of ferulic and caffeic acids in coffee beans. There are about a dozen different compounds in chlorogenic acids. If raw coffee contains 7-10% chlorogenic acids, then roasted coffee contains 2.5 times less. This is explained by the fact that acids are destroyed during heat treatment of grains. At the same time, the proportion of quinic acid and caffeic acid in coffee increases. Chlorogenic acids have also been found to directly affect the color of roasted coffee.

What does a caffeine molecule look like?

Let's take a closer look at the structure of the caffeine molecule. This will help you understand how it works. Scientists have found that raw coffee beans contain half the carbohydrates. They are a kind of fuel for our body. They give energy to every cell of ours. These carbohydrates are mainly simple sugars (fructose, sucrose) and polysaccharides (fiber, cellulose, pectin). These substances are simply irreplaceable for our brain. They are directly involved in its nutrition. Sugars and polysaccharides nourish nerve cells. This ensures normal functioning of the brain and nervous system.

Coffee also contains minerals:

• magnesium;
• potassium;
• calcium.

These are the most important minerals of inorganic origin. They are found in bones and muscles. Without them, proper functioning of blood vessels and the brain is impossible. These minerals ensure the normal functioning of the heart muscle. Scientists have found that raw coffee beans contain about 850 different essential compounds. But in the fried product their quantity is reduced by almost two and a half times and amounts to 350 units. They provide the amazing aroma of coffee. It is not surprising that this drink has long been recognized as the most fragrant.

What nutritional value does coffee have?

Like any product, coffee has its own nutritional value. As you know, it is measured in calories. Let’s immediately make a reservation that natural black coffee without sugar and other additives has a minimum amount of calories. This is explained by the fact that the substances it contains are very easily absorbed. The body easily absorbs them and quickly digests them. This process is also stimulated by caffeine, which is found in large quantities in coffee beans. So everyone. Anyone who doesn’t want to gain extra pounds can be recommended to regularly drink a cup of natural, fresh coffee. But to avoid complications, you should drink no more than two cups of this weak drink per day. To prevent your body from being overloaded with calories, it is better not to add sugar, cream or milk to your coffee. The ideal option is black coffee without sugar. If you have a sweet tooth and don’t like to feel the bitter taste in your mouth from coffee, then add a little sugar to it. One teaspoon will be enough.

How healthy is coffee?

If you regularly drink this invigorating drink, you must be wondering how beneficial it is for our body. The type of coffee and method of preparation also play an important role. This product is rich in proteins, fats, it contains vitamins A, B, E, D, as well as such important minerals as phosphorus, potassium, calcium. All these substances provide the effect that coffee has on the body. It can be either positive or negative. This contradictory influence is due to the fact that coffee contains simply a huge number of components. Each of them affects our body in its own way. In addition, a person may have individual susceptibility to them. It is also important how much drink a person drinks per day, what concentration.

Doctors have calculated a safe dose of coffee for humans - a couple of cups per day. However, you should not brew a drink that is too strong. Try to brew coffee of medium concentration, and do not drink it more than twice a day. Also, do not drink coffee later than 4 hours before bedtime.

Let's take a closer look at exactly how coffee affects our body. Here are the main characteristics of its effect on the human body:

1. If you regularly drink strong enough coffee, you can cause coffee addiction. To do this, you need to drink an amount of coffee per day that contains about 1000 mg of caffeine. This is what causes the addictive phenomenon. This addiction is very similar to alcohol or nicotine addiction. Getting used to coffee is that over time, the substances begin to have less and less pronounced effects on a person who drinks this drink in sufficiently large quantities. If at first coffee invigorates well and stimulates performance, then as you get used to it, this effect becomes less pronounced. To get the initial effect, a person is forced to drink more and more coffee. This is where getting used to it begins.
2. Diuretic effect. Scientists have long noticed. That coffee has a pronounced diuretic effect. True, it doesn't last long. At the same time, excess fluid is removed from the body. This is why it is recommended to drink coffee for swelling. But if you eat or drink too much of it, you risk getting dehydrated. And this is already fraught with disruption of the functioning of internal organs. To prevent disastrous consequences, nutritionists recommend not overusing coffee. After you've enjoyed a cup of coffee, drink a glass of clean water and you won't get dehydrated. If you still brought it to this. When the first signs of dehydration begin to appear, just start drinking more. For this, clean, unboiled water, preferably bottled, is best suited. You can also supplement it with a glass of mineral water. It will replenish mineral deficiency.
3. Coffee may slightly increase your blood pressure. This effect is due to the fact that this invigorating drink stimulates blood vessels. They become toned, and the pressure rises slightly. That is why it is not recommended to drink coffee for those who suffer from hypertension. This drink can immediately increase blood pressure by 15 mmHg. Moreover, this indicator applies to those coffee lovers who do not suffer from various vascular and heart diseases. But for the latter, pressure readings can jump significantly higher than 15 mm. But for some people, after drinking coffee, their blood pressure may, on the contrary, drop. This reaction of the body is due to the fact that coffee has a diuretic effect. This may also be due to the individual characteristics of the body. But basically, coffee is very useful for those who are prone to low blood pressure. In hypotensive patients, after a cup of aromatic drink, blood pressure can stabilize, performance increases, and headaches go away.
4. Coffee may affect the functioning of the heart. True, this influence is indirect. But indirectly this drink affects the functioning of the heart in the following way. After that. As caffeine enters the body, the nervous system is stimulated. After stimulation of the central nervous system, blood pressure increases. But the increased pressure itself begins to stimulate the heart. It accelerates its rhythm, the load on it increases. The degree of increase in load will depend on the dose of caffeine, the general condition of the body, as well as the individual sensitivity of the coffee components.
5. Drinking unfiltered coffee regularly can cause an increase in cholesterol levels in your blood. This is extremely undesirable, since elevated cholesterol levels lead to blockage of blood vessels and their pathologies. This is fraught with problems with blood pressure. Over time, a stroke or heart attack may even develop.
6. Coffee can increase the level of attention and stimulate memory. This effect is associated with its effect on the central nervous system. After stimulating the nervous system, a person’s brain activity improves. This means that coffee can actually improve performance. But this phenomenon is temporary. The pronounced effect does not last long - from half an hour to two hours after drinking the coffee. Interestingly, this drink can also improve your mood. It is even recommended to drink it in the initial stages of depression. The effect of the drink on the body will also depend on the individual characteristics of the person and his state of health.
7. The effect of some medications may be enhanced. We are talking, first of all, about the effect of painkillers. Caffeine enhances the effect of analgin and acetylsalicylic acid.
8. Interestingly, according to scientists, caffeine reduces the risk of developing Alzheimer's and Parkinson's diseases. This is due to the fact that it directly affects the neurons of our brain, and also temporarily constricts blood vessels. At the same time, the brain and blood vessels receive a kind of training.
9. If you regularly drink natural coffee, you will begin to suffer less from constipation.
10. The risk of developing liver pathologies, in particular cirrhosis, is reduced.
11. Women are less likely to develop breast cancer.
12. In older people, coffee can reduce bone density. This is due to its diuretic effect. Since in old age calcium is absorbed worse, and with a diuretic effect it is washed out faster. This can lead to brittle bones. This increases the risk of cracks and fractures.
13. Urolithiasis may develop. This applies, first of all, to those coffee lovers who drink more than two cups a day.
14. It is not recommended to drink coffee during pregnancy and lactation. It can cause increased blood pressure and negatively affect the fetus. Anemia of the placenta and even miscarriage may also develop. Coffee can cause low weight gain in newborns.

So, we tried to tell you as clearly as possible about the composition of coffee beans. Now you know its main components and their effect on the human body.

Why do we love coffee? The answer to this question is quite obvious - some people need 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 prepared. The only thing we know is that caffeine wakes us up in the morning and helps us function 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 a surprisingly 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 raw materials contain several hundred chemical compounds, but 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 consist of carbohydrates - they account for about half of the total mass. When fried, the amount of some of them decreases, and sucrose turns into caramel. It is responsible for the brown color of the future coffee drink. Also, during the heat treatment, a substance called kafeol 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 are accustomed to believe, that is responsible for the taste and aroma component. The latter is also an alkaloid 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 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 influenced by a chemical substance such as tannin. First of all, it is responsible for binding polysaccharides and proteins. In green grains, the percentage of the substance is about seven percent. When roasting, it is destroyed, but this is what gives the grain its 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 coffee contains is protein. Its amount is about 10% of the total amount of all substances.

Speaking about the chemical composition of grains, do not forget about vitamins and minerals, of which there are also a lot. What is really abundant here is vitamin B3. This substance affects metabolism in the body. In addition to B3, coffee also contains other important microelements. 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 the drink so beloved by many can be good for health, naturally, if consumed correctly.

Those who have problems with the cardiovascular and nervous systems, gastritis, ulcers, and rectal diseases should not drink coffee.

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

What can you say about instant drinks?

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

True, in stores you can find instant coffee labeled “organic”. This powder will not contain any artificial additives, only coffee extract. Accordingly, the price of such powder will be significantly higher. True, this guarantees only a natural composition, 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 present here, if present, then in small quantities. What cannot be taken away from instant coffee is the ease of brewing and long life. But is it really worth giving up the pleasure of drinking a cup of aromatic, tasty, and most importantly, natural drink?

photo: depositphotos.com/jirkaejc, Julia_Arda, muha04

Good afternoon dear friends! Coffee is one of the drinks that is consumed by quite a lot of people, regardless of their place of residence and nationality. Coffee contains a large number of organic and inorganic substances, which have a significant impact on the entire human body as a whole.

What do we know about coffee? Many of us can name only one single substance in coffee - caffeine, which affects us and gives us energy.

However, in fact, the chemical composition of this drink is very complex and is represented by many different substances, which many are not even aware of.

For example, roasted coffee contains over 1000 chemical compounds of various types. So, a small part of what is included in a coffee drink is represented by proteins, amino acids, alkaloids, minerals and many other substances.

Chemical composition of coffee

Many people are concerned and interested in the question: what is included in coffee? The chemical composition of coffee consists of chemical compounds that are found in the green beans and then added as they are roasted.

This suggests that roasted grains contain many more different substances than green ones. As mentioned above, there are more than 1000 such substances, where about 800 determine the taste of the drink.

A study of the chemical composition of coffee suggests that the main active ingredients in it are the following:

• Caffeine. It is he who helps us wake up in the morning and gives us energy for the whole day. Everyone who prefers it knows about the content of this substance in the drink. It is worth noting that caffeine was named after coffee, since it was first obtained from coffee beans. The substance helps improve performance and awaken mental abilities. To make a real coffee drink, it must contain caffeine in an amount of 0.7%. This figure will depend on the ripeness of the coffee beans and the degree of roasting. So, 1 tsp. Ready-made ground coffee contains about 0.1-0.2 g of caffeine. It is important to remember that it is recommended to drink a serving of coffee at a time not exceeding 0.3 g of pure caffeine. You will be able to enjoy your drink again no sooner than after 4 hours.
• Trigonelline. It has no taste or smell, but when heated it becomes a different substance and gives the drink its aroma.
• Vitamin B3. Stimulates the nervous system.
• Nicotinic acid, when combined with trigonelline during heating, ensures the content of Vitamin B3 in the required amount constantly.

The composition of the coffee bean is completely determined by the degree of roasting, as well as the plantation on which it was grown. After processing, the composition of coffee beans is represented by various types of vitamins. Here are the following vitamins:

• vitamin A, which helps the body develop and grow;
• vitamin D, which ensures the absorption of phosphorus and calcium;
• Vitamin E – stimulates the immune system.

In addition, black coffee contains amino acids and proteins. They give the body energy and nourish it. Amino acids in coffee beans of plant origin. They help the body recover and support immunity.

Coffee contains a large number of organic and inorganic substances, which have a significant effect on the entire human body as a whole.

Green coffee beans contain up to 50% carbohydrates. It contains sugars, polysaccharides and some other substances that help form the basis for nourishing the brain and nerve cells.

The minerals that make up ground coffee, as well as beans, are calcium, potassium and magnesium. They ensure strong bones, are also responsible for muscle function, and stimulate the functioning of the brain and heart.

However, it is worth remembering that excessive consumption of this drink does not lead to anything good, since an excess of caffeine causes the pulse to increase and the heart to beat at an accelerated pace.

Due to the high content of essential compounds in coffee beans, the drink is rightfully considered the most aromatic. Thus, green grains contain about 800 of these compounds, and fried grains - 350.

Composition of instant coffee

The chemical composition of instant coffee is far from the same as that of grain coffee. It is worth noting that this is because many instant drink manufacturers add various chemicals for flavor and color that are not found in natural coffee.

It should also be said that some manufacturers do not include any additional additives in the drink and retain the properties of natural coffee. Thus, instant coffee without additives includes the same elements as grain or ground coffee.

Some people prefer to drink without caffeine, due to the fact that not everyone can drink it due to insomnia, nervous breakdowns and other diseases. Here, caffeine is replaced by a substance such as carbonic acid.

Most instant coffee contains no more than 20% of the natural elements that should be in it and about 80% - flavors, dyes and other additives.

Based on this, it becomes clear that a grain or ground drink can never be replaced with a soluble one due to the naturalness of the former. If you can’t devote enough time to preparing the delicacy, then you should find instant coffee that does not contain additional substances. As a rule, such a drink is called organic, which means natural.

Nutritional value of coffee

Coffee is varied in its composition, but any type is low in calories, which allows the drink to be consumed even by those who are on a diet. It's a different matter when it comes to coffee with milk or cream and sugar. Here the calorie content is significantly increased due to additives.

Thus, pure coffee can be drunk often, if we consider this issue from the calorie side. However, it is important to remember to use the product in moderation.

Coffee, as mentioned above, can have different composition depending on the variety.

However, the chemical composition of coffee in the table in various sources suggests that the content of substances in different types of coffee is approximately the same. So, per 100 g of dry product there are:

• fats – 0.6 g;
• proteins – 0.2 g;
• carbohydrates – 0.1 g;
• calcium – about 5 mg;
• vitamin B3 – 0.6 mg;
• potassium – 9 mg;
• iron – 2 mg;
• phosphorus – 7 mg.

The chemical composition of coffee beans is quite rich, which allows it to act on the human body both positively and negatively. Only he himself can know how a treat will affect a particular person, since there are contraindications to consuming the treat for some people.

This is often due to the caffeine content. For example, the drink is not recommended for people with high blood pressure.

Instant coffee without additives includes the same elements as grain or ground coffee.

It is worth considering in more detail the effect of delicacy on the human body:

• Excessive consumption of the drink is equivalent to addiction. This is due to excessive intake of caffeine, which is contained in this drink. This addiction can be equated to alcohol or any other;
• The treat has a diuretic property, so if you are dehydrated, it is not recommended to drink it in any form. It is best in this case to replace the drink with water;
• people who do not have heart problems or blood pressure may experience a slight increase in blood pressure after drinking the drink. If the drink is consumed by a hypertensive person, the blood pressure may rise much higher than in healthy people. In this regard, the use of the drink should be postponed or replaced with others. Thus, it is recommended to drink coffee with a reduced caffeine content or without it at all. Fortunately, now you can find it without problems in any store;
• The drink has no effect on the heart. The misconception is that, on the contrary, it worsens the functioning of the heart and is confused with an increase in blood pressure or nervous excitability;
• unfiltered delicacies often increase cholesterol, which complicates the functioning of blood vessels and leads to increased blood pressure;
• The increase in productivity, performance and mental focus only occurs for a while. So, the duration of the drink in this case can be from 30 minutes to 2 hours. You won’t be able to use this effect all day;
• oddly enough, coffee can enhance the effect of some medications, such as aspirin, analgin and some antispasmodics;
• the drink reduces the likelihood of certain diseases, such as Alzheimer's disease. This effect can be explained by the fact that the brain is trained due to the vasoconstrictor effect;
• the treat prevents constipation, breast cancer and even cirrhosis of the liver;
• The older generation should limit their consumption of the drink due to the fact that the drink reduces bone density. Often this leads to cracks and fractures appearing almost out of nowhere;
• those who drink more than 2 cups of drink per day risk increasing the likelihood of developing kidney stones;
• coffee increases the likelihood of developing pathologies in the fetus if a pregnant woman drinks more than 1 serving per day. Some women generally prefer to give up drinking during pregnancy in order not to harm their baby.

After analyzing this list, we can say that coffee can affect a person’s condition and his body, both positively and negatively.

Coffee is one of the few drinks of natural origin, the biochemical composition of which includes a huge number of organic and inorganic elements that have a significant impact on the condition and functioning of all systems and tissue structures of the human body. Despite all their efforts, scientists have not yet been able to create an artificial coffee substitute that can accurately convey its unique aroma and taste. A situation exactly reminiscent of futile attempts to create an analogue of breast milk. Obviously, nature is reluctant to reveal its treasured secrets to man.

About the chemical composition of coffee

The biochemical composition of coffee is extremely complex: it contains about two thousand chemical components, the combination of which gives its characteristic taste and aroma. Only half of these substances have been studied. Thanks to modern methods of chemical analysis, it has been established that natural coffee contains several hundred organic substances that determine the taste and aromatic properties of our favorite drink, and each variety has its own unique set of these components.

The richness of the chemical composition and the percentage of substances in coffee beans are determined by climatic conditions and soil characteristics, and the characteristics of their taste and aroma are determined by the roasting technology and method of preparation, during which natural substances undergo a number of complex chemical metamorphoses. Thus, each stage of processing coffee beans (including the preparation of the drink) consistently ends with a modification of their chemical composition. The essence of the processes occurring in this case is the subject of study by many world research centers.

Composition of green coffee beans

A quarter of the mass of raw coffee beans comes from caffeine, chlorogenic acid, trigonelline, mineral salts and vegetable proteins. The remaining three-quarters of the weight is made up of plant fiber, coffee oil and water. Coffee fruits are champions in the content of chlorogenic acid, which gives them a tart, slightly acidic taste: no other product contains it in such quantities.

Arabica beans have a low caffeine content, while low-grade African Robusta fruits have the highest amount of caffeine (over 3%). The process of storing coffee does not affect the caffeine content in any way, but roasting leads to an increase in its mass fraction. The content of coffee oil in different types of coffee varies significantly. Indian varieties have the least amount of fat. The highest protein content is in African robusta.

About the composition of roasted coffee beans

The composition of roasted coffee beans is determined not only by the growing conditions, but also by the duration of roasting. During this process, the grains, losing a significant part of the liquid and from 14 to 23% of the weight, at the same time (due to gas formation) acquire additional volume. Raw coffee fruits contain many alkaloids, phenols, proteins, amino acids, disaccharides, lipids, mineral salts, natural acids and a number of components present in trace quantities.

During roasting, new chemical compounds are formed in them, enriching the already diverse chemical composition, numbering more than a thousand components, eight hundred of which determine the taste of the finished drink. In addition to the delicious aroma, roasting gives the beans the well-known dark color. Roasting rids the grains of their moisture content; When sugar is caramelized, caramel is formed (which colors the beans brown) and caffeol, a multicomponent compound that is the source of the characteristic coffee aroma. In the process of decomposition of chlorogenic acid, which is contained in significant quantities in the fruit, coffee acquires its astringent tart flavor.

Roasting is equally destructive to tannins - natural substances that give the drink a bitter taste. With this in mind, beans should be roasted carefully. Another source of unique aroma is the alkaloid trigonelline, the destruction of which during roasting produces nicotinic acid. The famous alkaloid caffeine tolerates this process completely differently. After frying the fruits, which lose most of their moisture, its amount (as a percentage of the mass of raw materials) even increases.

The invigorating effect of coffee is provided by the presence of caffeine. Researchers have always been interested in the question, thanks to which component contained in coffee fruits, the drink prepared from them has the ability to drive away sleep and give vigor.

This crystalline, colorless substance was isolated by the German researcher Runge in 1819 and was named caffeine. Upon further research, caffeine was found in tea leaves, mate, cola, guarana, and cocoa. It has been found that plants synthesize it to protect themselves from insect pests and to attract pollinators. Caffeine increases motor activity, speeds up reactions, improves brain activity and nervous system function. The caffeine content is determined by the type of coffee. In the best Arabica varieties, characterized by a mild taste and pleasant aroma, the beans contain from 0.5 to 1.5% caffeine, and in Robusta fruits it can be from 1.5 to 4.5%.

Caffeine is an alkaloid; after roasting, it does not disintegrate and its amount does not decrease when compared with green caffeine. More precisely, the amount of caffeine in the roasted bean increases, but only in proportion to the decrease in the weight of the bean, which loses liquid during roasting.

The chemical composition of coffee depends on its variety, as well as on the method and level of roasting. 100 ml of a drink made from fried fruits contains (on average): proteins (0.2 g), fats (0.5 g), carbohydrates (0.2 g). Convinced fans of strong black coffee become almost as dependent on it as smokers are on tobacco. Despite the harm caused to the body by countless cups of coffee, lovers of this drink cannot deny themselves the pleasure of drinking another cup. Meanwhile, drinking natural coffee is contraindicated for patients with gastric and duodenal ulcers, diseases of the cardiovascular system, chronic colitis and enterocolitis. It is not advisable to drink it if you are prone to neuroses, insomnia and thyrotoxicosis.

What should people do who are contraindicated from drinking coffee? Do they really need to forget the taste of this wonderful drink forever? Of course this is not true. In modern supermarkets you can find many coffee drinks, the composition of which either does not contain natural coffee, or its amount does not exceed 35%. When preparing coffee drinks, plant raw materials are used, during the brewing process they produce a drink whose taste and aroma resembles natural coffee, and the absence of caffeine and caffeine makes it safe for the health of people suffering from the above ailments. In addition, some countries have learned to make decaffeinated coffee, the caffeine content of which is almost zero.