Man was showing an interest to the chemical contents of coffee beans during long time of using them. Researchers were interested in substances, which are giving to coffee the taste, aroma and vivacity. Naturally, that coffee drink isn’t valuable as a source of protein, fat and carbohydrate. So, what invigorative substances does coffee contain? As every plant, coffee tree gets from the soil number of mineral substances that are necessary for normal development of living of the plant through the rootage. These mineral substances transform in ashes that remains when the coffee beans are burnt. It contains nitrogen, iron, potassium, calcium, magnesium, sodium, sulfur, phosphorus, chlorine and other elements as various compounds. Neither of further elements is dangerous for man’s health. On the contrary, all of them are necessary for normal functioning of organism in fixed quantities. For example, the iron is a part of haemoglobin of a blood, and sodium chloride forms the liquid part of blood – plasma. Normal rhythm of cardiac activity depends on presence of natrium, calcium and potassium. Calcium and phosphorus are the part of the bone tissue. Nitrogen and sulfur are the basis of amino acids albumens, which are forming the muscular tissue and other soft tissues of organism.

In 1819 french scientist Runge evolve insipid crystals, aqueous solution of which surpassed coffee broth in many scores of times in stimulate action. That substance, which is related to alkaloids, was named caffeine. But 80 years of painstaking work of scientist past before the final composition of caffeine and its structural formula were established. Basing on that formula, german chemist Fisher found synthetic caffeine and proved the accuracy of structural formula in 1897.

It is interesting, that coffee used in the classical Arabic medicine as a medical tool in 900-1000 A.D. It was found out as “bunchum” by ancient Arabic doctor and alchemist Abu Bakhra Mohamed ibn Zakhari ia al Razi, who was also known as Razes. However, during the growing of consumption of coffee as a drink, his medical properties started forgetting. Coffee was born the second time as a medical tool only after caffeine’s discovery. Now caffeine is using successfully in a medical practice against many diseases. It is the part of mare than twenty different descriptions of medications that are conductive in reconstruction of disturbed functions of some of man’s organs. Receptions of the coffee drink containing caffeine in the reception of small-dozed medications, and could be regarded as a prophylactic action, which is stimulating and maintaining the functional actions of some important human organs. In different kinds of coffee there is various quality of caffeine – 1-2 percents on average.

The second alkaloid containing in coffee is trigonelline. This alkaloid isn’t stimulating, but he is important in forming of aroma of roasted coffee. Besides, coffee contains eight vitamins from B group, whish are really important for human. They are regulating the course of many biochemical processes and preventing a number of hard illnesses. Organic acids are of great value, which are the part of coffee beans. They are producing intensive gastric secretion and are promoting the good digestibling of food. According to the modern data, coffee contains more than 30 organic acids: as prevalent as malic acid, citric acid, acetic acid and such infrequent as coffee acid, cinchona and others. Majority organic acids in green coffee are as salts, metals and only 1/3 part of them – uncombined. The most essential is chlorogenic acid. Evidently, it imparts astringent relish and feeling of fullness. It’s abundance in coffee of different sorts varies from 4% to 8%.

But roasted coffee is more manifold in substances. Complicated physic-chemical changes are making during roasting, which are creating new substances, causing aroma, color and taste of roasted beans. During the roasting the coffee bean are expanding and loosing near 18 % of their weight. These processes are occurring thanks to evaporation of moisture and partial decomposition of organic matter such as: protein, fat, sugar, cellulose, organic acid, etc. During the roasting caffeine is changing lightly. But according to changing the weight of roasted coffee percentage of caffeine is growing up. Chemical changes in coffee during the roasting are very complicated and aren’t completely learned yet. Substances that are forming coffee aroma are volatile and they are easy oxidizing by the atmospheric oxygen. That is why it is highly recommended to roast coffee directly before usage or to keep it brief time in hermetically sealed glass cans or in canisters. Substances contained in coffee and are determinant of color, aroma and taste are passing into drink during the cooking process. Sum total of substances that are passing into the drink is near 30%, which is near 85% of all soluble substance contained in coffee. Cited data doesn’t reveal all variety of substances of coffee. The just give us a general idea about some base materials discovered by scientists.

Some materials of current article were taken from COFFEE.RU site