Tea

Tea, a beverage widely used in the daily life of many countries, including the USSR. It is obtained by infusing the leaves of a special plant (Thea chinensis; a large shrub cultivated in China and other countries, and in recent years also in the Transcaucasian republics of the Union) in hot water. Through special processing of the buds and leaves of this plant, so-called commercial tea is obtained, which acquires certain additional flavor properties through this processing. Production waste (tea dust, small twigs, etc.) yields special low-grade teas, so-called brick tea and compressed tea. The main flavor component of tea is the alkaloid theine, identical in composition to caffeine (C₈H₁₀N₄O₂); its percentage content increases in high-grade teas, reaching 4.7% (Khlopin). The aroma of tea depends on the essential oils contained in it. In addition, tea contains tannins, nitrogenous compounds, fats, etc. The physiological effect of tea as a hot beverage consists of its influence on the nervous system (vasomotor centers), in particular it dulls the sense of fatigue. During the period of private ownership in old Russia, commercial tea was subjected to numerous adulterations and falsifications. These included mixing in used tea that had already been consumed, mixing in leaves of other plants, for example lingonberry, blueberry, strawberry, Ivan tea (so-called Epilobium angustifolium - willow herb, tea "kapor-ka"). In addition, artificial colorings for tea were often used - indigo, corn, etc. For detection, the botanical-microscopic method (shape of tea leaves under a microscope) was used, as well as some chemical methods. Average composition of tea (in %) (according to Khlopin): water 8.46, nitrogenous substances 24.13, theine 2.79, essential extracts (fat) 8.24, tannins 12.35, non-nitrogenous substances 30.28, cellulose 10.61, ash: soluble in water 2.97, insoluble in water 2.96, aqueous extract 38.76.