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26BIOLOGICAL SCIENCES
THE EFFECT OF ALTITUDE TEA PLANTATIONS ABOVE SEA LEVEL ON THE CHEMICAL COMPOSITION OF TEA
Platonova N.
PhD student, Federal State Budgetary Scientific Institution «Russian Research Institute of Floriculture and Subtropical Crops»
Belous O.
Doctor Biological Science, Chief Scientist at Plants Biotechnology, Biochemistry and Physiology Laboratory, Federal State Budgetary Scientific Institution «Russian Research
Institute of Floriculture and Subtropical Crops» Sochi Institute of Design, Business' and Low
ABSTRACT
The article presents data on the determination of chemical components in black tea. As objects of research were selected teas produced from raw materials grown on the plantations of Krasnodar region and the largest tea producing countries. We showed that all varieties of tea Krasnodar domestic producers are high quality. Differences in growing conditions and processing of black tea are affected the content of polyphenols and flavonoids. The contents of the main quantitative characteristics of the Krasnodar tea are different from the world of brands (polyphenols - of 1.62 mg/g; thearubigins was 0.90 mg/g and theaflavin - 0.09 mg/g), which, however, does not affect its taste and aroma performance.
Keywords: tea, environmental conditions, biochemical analysis, polyphenols, flavonoids
Introduction
Tea refers to the food product, the value of which is determined by taste and aromatic characteristics [4; 5; 6; 7; 2]. These indicators are caused by a complex chemical composition of tea leaves (raw material). One of the main places among the substances included in the composition of the tea leaves is a complex of tannins. All the basic properties of the finished product - its color, taste and aroma in different degrees are related to their reactions in tea leaves.
Tannins are the most mobile and active substances so they are changed under different growth conditions. Extractives substances which represent the sum of all soluble in hot water substances are also one of the important indicators of quality, as the green sheet, and the finished product. The specific astringent, pleasantly bitter flavor of the drink and the reddish color of the tea infusion depend on extractives substances.
A study of the chemical composition of green tea leaves was started in 1936-1938, the years at the Sochi experiment station, now the Institute of floriculture and subtropical crops [8]. Currently, all-Russian research Institute of floriculture and subtropical crops has been working to establish the influence of different factors on the changes in the biochemical composition of the green sheet depending on the area of growing tea plants, weather conditions, varieties, farming practices, maturity of the leaf, and many other factors, and the impact of raw materials on the quality of the finished tea [1; 2; 9].
The factors that affect the accumulation of substances, determining the organoleptic tea include soil conditions, agricultural activities, hydrothermal (combination of temperature and humidity, precipitation) and orographic factors (slope exposure and the height
of the plantations above sea level) [1; 2; 3; 7; 10; 11; 14].
Material and methods
As object of research used samples of black tea of local producers, as well as tea grown in the plantations of India, Ceylon, China and Kenya (blending and packaging is produced by company «OXALIS Tea» on the territory of the Czech Republic).
The biochemical determination was performed at the laboratory of the University of veterinary and pharmacy (Brno, Czech Republic): determination of polyphenols - spectrophotometric method using the reagent Folina-Cocalteu as a reagent [13]; determination of fla-vonoids - spectrophotometry [12]. Statistical data processing was carried out using the programs Stat-graphics and MS Excel.
Results and discussion
The study of tannin and extractive substances in the tea leaves allowed us to determine the main regularities in their synthesis, not only the dependence of the accumulation of quality indicators from the factors listed above. In addition, in our studies we compared the quality characteristics of tea grown and produced on the territory of Krasnodar region, with tea grown on plantations in India, Ceylon, China and Kenya. It is believed that high-quality tea can be grown only at an altitude of 1500 m and above. Thus, we investigated the physic-and-chemical composition of tea from Singbulli Daijeeling (plantation in the province of Singbulli, located in the mountainous regions of Northern India at an altitude of 1100 m above sea level - considered to be one of the best teas), tea from Darjeeling Puttabong (tea plantation in the province of Puttabong at the altitude of 2000-2200 meters above sea level), Kenya Flowery
Broken Orange Pekoe tea (grown in Kenya at a height of 2.5 thousand meters above sea level), Ceylon Dimbula tea(grown in the province Dimbula at an altitude of 1400 m above sea level), Keemun black tea (grown in the plantations in the country area Keemun, Gunji, Guichi), etc. Our scientist experimentally proved that due to the sharp contrast of temperatures in the Russian mountains, the tea plant grows more slowly. For the year pick up usually 3, rarely 4 harvest leaves, but the leaves themselves thus turn out much more flavorful and rich. In General, the quality high mountain tea is always higher in comparison with the plains. We noted that in these teas (high mountain) more phenolic compounds (up to 6.19 mg/g at tea grown in the province of Singbulli, India), which forms
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the unforgettable taste and aroma, when analyzed or-ganoleptic (tea-tester) assessment (Figure 1). But tea from Kenya has more tearubigin (about 6.79 mg/g) and taeflavin (0.35 mg/g) than other tea. We show that contents of taeflavin are variability substances during its oxidation and depend from condition manufacturing. The absence or presence of theaflavins in tea is quite accurate and a good indicator of the quality of tea. So, a constant ratio of theaflavins and thearubigins in a good tea is 1:10, and in bad - 1:20. High mountain teas are rightly classified in a separate group of teas with the best quality. But ratio of theaflavins and thearubigins at Krasnodar tea also are 1:10 and this is a good tea (Figure 1).
Krasnodar (Russia)
Darjeeling Singbulli
Darjeeling Puttabong
Keemun
Kenya
Ceylon
polyphenols, mg/g thearubigin, mg/g theaflavin, mg/g
Figure 1: the content ofpolyphenols and flavonoids in the samples of the finished tea
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All tea plantations grown in the Krasnodar region located at low altitudes, the plants are of the Chinese big leaf species (at the time, as in India, Ceylon and Kenya - Assam variety), and are characterized by lower values of the polyphenols substances forming the aroma and taste (an average of 1.62 mg/g). At all world plantations have only two main species of tea plant -Thea sinensis and Thea assamica - they differ not only morphologically, but also in chemical composition, so the teas from different species of the tea plant, different taste and aroma qualities. The tea plant is sensitive to changes in the external environment, leading to differences in the chemical composition of the leaf, harvested in different places of growth. The leaves of the Northern varieties of the tea (Chinese and Japanese) contain less soluble (extractive) substances and tannin than the leaves of the southern (Indian). Therefore, the tea of Chinese varieties (for example, teas from the Keemun varieties) has a more delicate, mild flavor and aroma than tea Assam varieties.
Plantation from «Sholohovsky tea» - the most «Alpine» is located at an altitude of 600 m above sea level; plantation of «Hosta Tea» - from 300 to 550 m
above sea level; «Shapsug tea» - the so-called zone of low foothills; «Matsesta tea» has a plantation of over 400 meters above sea level, but not higher than 600 m above sea level. The plantation from «Dagomys tea» have a complex orography - the plantations are located on flat areas, and mountain, but to the height of 500 m above sea level. The leaves of the tea from Krasnodar plantation have contained less extractive substances and tannin than the leaves of the other tea.
The conditions of the black sea coast of Krasnodar region (Sochi) belong to the wet subtropical with high humidity (average 75 %) and high rainfall (average 1,500 mm per year). The whole territory is characterized by microclimatic areas. Marked vertical zoning of climate change: when climbing every 100 meters the temperature drops by 0.6 °C in summer and 0.3 °C in winter, therefore, the climate changes from subtropical to cold temperate Western type, then the cold climate of the meadow belt, etc. These facts are stops the advancement of the tea plantations in the mountains, the upper boundary is 500 - 600 m above sea level.
Thus, in the Krasnodar region the tea is grown in the Northern border of the subtropics (up to 43° - 50 °
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North latitude), all plantations belong to the so-called «low-altitude», the highest possible altitude are 600 m above sea level. Therefore, the quality of tea differs from tea high mountain group. The analysis of the extract, the attention is drawn to the fact that the extract Krasnodar black tea has lower amounts of polyphenols less intense than in other samples. We need to increase the extraction time slightly for optimal sensitivity when viewed tea on a spectrophotometer. However, the extracts Krasnodar tea are characterized by a rich aroma and a milder taste. The tea analysis has shown that unlike other global tea, the Krasnodar tea has a pleasant aftertaste which can last for ten to fifteen minutes at a time, but other tea quickly lose this property.
Conclusion
Tea plants grown outside the Russian Federation at in plantations located at altitudes above 1 200 m above sea level have a distinctive organoleptic characteristics, are characterized by a high content of phenolic compounds of the group, standing out as a separate type of tea high - mountain tea.
Tea plants grown on plantations in Krasnodar region, growing at altitudes up to 600 m above sea level, the polyphenol content in them is lower, which affects the taste (but not aromatic) characteristics.
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