Tea chemistry

May 13, 2019

In this article, we will not only treat the chemical composition of the tea, but we will begin with the etymology of its name, description of the plant, classification of tea leaves, benefits of tea in the diet, the organic and inorganic substances that compose it and data on its consumption around the world.

Name:

The word tea, TEA in English, comes from the Amoy dialect; TE, although many argue that it derives from Mandarin Chinese "cha". The word was acquired by the Dutch who traded the plant of Chinese origin through the port of Amoy, in the province of Fujian.

The tea plant :

The tea plant (the synthesis) is a perennial plant belonging to the family of camellias, with lanceolate or elliptical leaves, with white or cream-colored flowers, and with a capsule fruit with a single seed.

Three very similar varieties are used in industrial tea production:


  • Camellia Sinesis (China, Japan, Tibet)
  • Camellia Assamica (India)
  • Lasiocalyx, subspecies della Camellia Assamica (cambodia)


The ideal habitat of the tea plant should be humid and hot, at high altitudes. The plant can reach several meters in height if it is allowed to grow freely. However, this is not the case of crops for industrial purposes, in which it does not exceed one meter in height. In this way, the work of selection and collection of the sheets is facilitated.

Classification of tea leaves:


  • Orange Pekoe (OP): long, thin and fibrous leaves that sometimes have a golden tip; the infusions are light or pale
  • Pekoe (Pek.): The leaves are shorter and not as fibrous as the OP, but the infusions usually have more color
  • Souchong (Sou.): Thicker, rounded leaves, with pale infusions

The lower grades of the split sheet that are used today are:


  • Broken Orange Pekoe (BOP): one of the most sought after; much smaller than any of the whole leaf and golden tip grades; The infusions have the strength and good color
  • Broken Pekoe (BP): slightly larger than BOP, with significantly less color in the cup; useful as filling in a mixture
  • Broken Pekoe Souchong (BPS): slightly larger than BP and consequently lighter in the cup, but also used as a filler in a mixture
  • Broken Orange Pekoe Fannings (BOPF): this degree is also very sought after, especially in the United Kingdom, and reaches quite high prices. It is much smaller than BOP and its main virtues are the speed of infusion and good color in the cup.
  • Dust (D.): crushed

"Flowery" variants of the main grades:


  • Flowery Orange Pekoe (FOP): smaller than OP leaves, also rolled along.
  • Golden Flowery Orange Pekoe (GFOP): same as FOP with some leaves showing a golden tip.
  • Tippy Golden Flowery Orange Pekoe (TGFOP): Same as GFOP but with all the golden tips. It is also classified as Finest Tippy Golden Flowery Orange Pekoe (FTGFOP).

Benefits of tea:

 Tea was considered medicine until the third century AD and it was not until the 4th and 5th centuries that it spread rapidly in China where it was drunk either for its restorative properties or for pleasure.



The leaves of green tea contain a large number of active ingredients such as caffeine (which is called teína, when it comes from tea), tannins, theophylline, Vitamins A, B1, B2, B12, E, P; calcium, and more than 300 active ingredients, including aromatic substances. Later in this article, we will deal more in detail with these molecules. These active principles vary in relation to the place of cultivation, and to the "age" of the leaf.

Tea prevents cell aging as it is an excellent antioxidant, also favors the reduction of cholesterol, helps to combat and prevent anemia by its iron content, improves immune defenses, is astringent, antimigraine, diuretic, protects the liver, decreases Stress levels 1 , helps to fight depression 2 , decreases hypercholesterolemia and is anticancer, among other benefits that are still being studied.

The black tea is the most popular variety of commercial and tea, and its benefits include the ability to decrease the absorption of triglycerides and cholesterol, reducing the risk of cardiovascular disease.

The green tea for its part, besides having the properties of black tea contains more antioxidants, lowers blood sugar and has antibiotic properties, as well as collaborating in strengthening bones thanks to its fluoride content.

Differences between green tea and black tea

Both types of tea come from the same plant, the Camellia Sinensis, but they are obtained through two very similar elaboration processes that differ by an additional step in obtaining black tea. The black tea, after the rolling of the leaves of the plant, these remain during two hours in fermentation (pseudo-fermentation), so that the polyphenols are oxidized completely.

The green tea, therefore, retains a higher content of chlorophyll (hence its name, given by the coloration provided by the presence of chlorophyll) and unoxidized polyphenols, catechins and tannins.

The black variety of tea, however, contains a greater amount of caffeine (theine) and contains more anthocyanins compared to green tea. In addition, from the oxidation of tannins derive the theaflavins and the tear begins that confer a reddish color to the drink.

Tea consumption data:

 The main world producers of Tea are:


  • China (1,744,431 TM / 2011)
  • India (1,028,098 TM / 2011)

The main consumers are:

  • the United Kingdom (2.2 kg per capita / 2012)
  • Turkey (2.1 kg per capita / 2012).

While in Latin America, Chile is the country that consumes more tea (0.6Kg per capita / 2012)

Around 3.9 million tons per year are consumed in the world, that is to say, 25 thousand cups of tea are consumed per second.



The chemistry of tea:

The taste, taste, color, and beneficial properties of tea are determined by the more than 500 organic compounds (representing 93 to 96.5% of the dry tea) it contains.

Fresh tea leaves contain between 75 to 78% of the water that is removed during the process. This leads to 4Kg of fresh leaves getting 1Kg. of finished tea.

The organic substances cited above are:


  • Proteins (from 20 to 30%)

  • Amino acids (from 1 to 5%)

  • Alkaloids (from 3 to 5%)

  • Phenols (from 20 to 35%)

  • Carbohydrates (from 20 to 25%)

  • Organic acids (from 3 to 5%)

  • Lipids (from 4 to 5%)

  • Pigments (from 0.6 to 1%)

  • Aromatic substances (from 0.005 to 0.03%)

  • Vitamins (from 0.6 to 1%)

  • Saponaria (from 0.07 to 0.1%)

  • Sterols (from 0.04 to 0.1%)


Among the major polyphenols in green tea are catechins (or flavonols) such as EC (epicatechin), ECG (epicatechin-gallate), EGC (epigallocatechin) and EGCG (epigallocatechin-3-gallate). The EGCG is of particular interest for its antioxidant, antiatherogenic and anticarcinogenic properties (intimately related properties).

Inorganic chemical composition of tea

Several scientific analyzes on the chemical composition of tea have shown that tea, in addition to carbon, hydrogen, oxygen and nitrogen, contains 27 mineral elements: phosphorus, potassium, magnesium, manganese, fluorine, aluminum, calcium, sodium, sulfur, iron , arsenic, copper, nickel, silicon, zinc, boron, molybdenum, lead, cadmium, cobalt, selenium, bromine, iodine, chromium, titanium, cerium and vanadium.

.
Below is a list of almost all the chemicals contained in the tea.


  • (DL) -GALLOCATECHIN
  • 1,4,6-TRIO-galloyl-GLUCOSE
  • 1-EPICATECHIN-GALLATE
  • 1-O-galloyl-4,6- (S) -HEXAHYDROXY-BETA-D-GLUCOSE
  • 2-AMINO-5- (N-ETHYL-CARBOXAMIDO) -PENTANOIC-ACID
  • 2-O- (BETA-1-ARABINOPYRANOSYL) -MYOINOSITOL
  • 2-O-BETA-1-ARABINOPYRANOSIDE-MYOINOSITOL
  • 2-PHENYL ETHYL-ALCOHOL
  • 5-ALPHA-TIRUCALLA-7,24-DIEN-3-BETA-OL
  • 6,8-DI-C-BETA-D-ARABINOPYRANOSYL-APIGENIN
  • 8-C-ASCORBYL-EPIGALLOCATECHIN-3-O-GALLATE
  • ALPHA-IONONE
  • ALPHA-TERPINEOL
  • ALUMINUM
  • AMMONIA (NH3)
  • ASSAMICAIN-A
  • ASSAMICAIN-B
  • ASSAMICAIN-C
  • BENZALDEHYDE
  • BENZYL-ALCOHOL
  • BETA-AMYRIN
  • BETA-CAROTENE
  • BETA-CYCLOCITRAL
  • BETA-GLUCOGALLIN
  • BETA-IONONE
  • CAFFEINE
  • CALCIUM
  • CARBOHYDRATES
  • CASTASTERONE
  • CATECHIN- (4-ALPHA-8) -EPIGALLOCATECHIN
  • CIS-JASMONE
  • CIS-LINALOL-OXIDE
  • COPER
  • D, L-CATECHIN
  • DAMMARADIENOL
  • DEGALLOYL-THEASINENSIN-F
  • DIPHENYLAMINE
  • EO
  • EPIAFZELECHIN
  • EPIAFZELECHIN-3-O-GALLATE
  • EPICATECHIN
  • EPICATECHIN- (4-BETA-8) EPIGALLOCATECHIN-3-O-GALLATE
  • EPICATECHIN-3,5-DI-O-GALLATE
  • EPICATECHIN-3- (3-O-METHYLSULFATE)
  • EPICATECHIN-3-O- (3-O-METHYL) -GALLATE
  • EPICATECHIN-3-O- (4-O-METHYL) -GALLATE
  • EPICATECHIN-3-O-GALLATE
  • EPICATECHIN-3-O-GALLATE- (4-BETA-8) EPIGALLOCATECHIN-3-O-GALLATE
  • EPICATECHIN-3-OP-HYDROXYBENZOATE
  • EPICATECHIN-EPIGALLOCATECHIN- (4-BETA-8) -3-O-galloyl
  • EPICATECHIN-GALLATE
  • EPIGALLOCATECHIN
  • EPIGALLOCATECHIN- (4-BETA - () - EPICATECHIN-3-O-GALLATE
  • EPIGALLOCATECHIN-3,3'-DI-O-GALLATE
  • EPIGALLOCATECHIN-3,4'-DI-O-GALLATE
  • EPIGALLOCATECHIN-3,5-DI-O-GALLATE
  • EPIGALLOCATECHIN-3- (3-O-METHYL-GALLATE) v197
  • EPIGALLOCATECHIN-3-O-CINNAMATE
  • EPIGALLOCATECHIN-3-O-GALLATE
  • EPIGALLOCATECHIN-3-OP-CAFFEOATE
  • EPIGALLOCATECHIN-3-OP-COUMARATE
  • EPIGALLOCATECHIN-GALLATE
  • EPITHEAFLAGALLINv6
  • EPITHEAFLAGALLIN-3-O-GALLATEv17
  • FAT
  • FIBER
  • GALLOCATECHIN- (4-ALPHA-8) EPICATECHIN
  • GALLOCATECHIN-GALLATE
  • GERANIOL2
  • GERMANICOL
  • HEPTA-TRANS-2-TRANSDIEN-4-1-AL
  • HEPA-1-AI
  • HEX-CIS-3-EN-1-AL
  • HEX-CIS-3-EN-1-OL
  • HEX-CIS-3-EN-1-OL-HEXANOATE
  • HEX-TRANS-2-EN-1-AL
  • HEX-TRANS-2-EN-1-OL
  • HEXAN-1-AL
  • IRON
  • L-GALLOCATECHIN
  • L-GALLOCATECHIN-GALLATE
  • LINALOOL
  • MAGNESIUM
  • MANGANESE
  • METHYL-AMINE
  • NEROLIDOL
  • NIACIN
  • NONAN-1-AL
  • OOLONGHOMOBISFLAVAN-A
  • OOLONGHOMOBISFLAVAN-B
  • OOLONGTHEANIN
  • OXALIC-ACID
  • PECTINS
  • PENT-1-EN-3-OL
  • PENT-CIS-2-EN-1-OL
  • PENT-CIS-3-EN-1-AL
  • PENTAN-1-OL
  • PHENOLS
  • PHENYLACETALDEHYDE
  • PHENYLACETIC-ACID
  • PHOSPHORUS
  • POLYPHENOLS
  • POTASSIUM
  • PROCYANIDIN-B-2
  • PROCYANIDIN-B-2-3'-O-GALLATE
  • PROCYANIDIN-B-2-3,3'-DI-O-GALLATE
  • PROCYANIDIN-B-3
  • PROCYANIDIN-B-4
  • PROCYANIDIN-B-4-3'-O-GALLATE
  • PROCYANIDIN-B-5-3-3'-DI-O-GALLATE
  • PROCYANIDIN-C-1
  • PRODELPHINIDIN-A-2-3'-O-GALLATE
  • PRODELPHINIDIN-B-2-3'-O-GALLATE
  • PRODELPHINIDIN-B-2-3-3'-DI-O-GALLATE
  • PRODELPHINIDIN-B-4
  • PRODELPHINIDIN-B-4-3'-O-GALLATE
  • PRODELPHINIDIN-B-5-3,3'-DI-O-GALLATE
  • PROTEIN
  • QUERCETIN
  • RIBOFLAVIN
  • RUTIN
  • S-METHYL-METHIONINE
  • SILICA
  • SODIUM
  • SPINASTERONE
  • STRICTININ
  • SULFUR
  • TANNINS
  • TARAXEROL
  • THEAFLAGALLIN
  • THEAFLAVIN
  • THEAFLAVIN-3'-O-GALLATE
  • THEAFLAVIN-3-3'-DI-O-GALLATE
  • THEANINE
  • THEARUBIGIN
  • Theasinensin A
  • THEASINENSIN-B
  • THEASINENSIN-C
  • THEASINENSIN-D
  • THEASINENSIN-E
  • THEASINENSIN-F
  • THEASINENSIN-G
  • THEOBROMINE
  • THEOGALLIN
  • THEOPHYLLINE
  • THIAMIN
  • TRANS-LINALOL-OXIDE
  • TOILET
  • ZINC


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