Chemical
Compounds in Tea
·
Polyphenols.
·
Amino
Acids.
·
Enzymes.
Polyphenol oxidase and peroxidase are the most important enzymes in tea leaves.
...
·
Pigments.
Plant pigments are responsible for absorbing light for photosynthesis. ...
·
Carbohydrates.
...
·
Methylxanthines.
·
Minerals.
...
·
Volatiles.
There
are an estimated 30,000 polyphenolic compounds in tea4, flavonoids
are arguably the most important group of polyphenols in tea and are the source
of the many health claims surrounding tea, and specifically tea
antioxidants. Within the flavonoid group, flavanols (also known as
flavan-3-ols) are the most prevalent. Flavanols are also referred to as
tannins, and during oxidation are converted to theaflavins and thearubigins—the
compounds responsible for the dark color and robust flavors notably present in
black teas.
The
major flavanols in tea are: catechin (C), epicatechin (EC), epicatechin gallate
(ECG), gallocatechin (GC), epigallocatechin (EGC), and epigallocatechin gallate
(EGCG). EGCG is the most active of these catechins and is often the subject of
studies regarding tea antioxidants. Tea flavanols are sometimes collectively
referred to as catechins.
Besides flavanols, tea flavonoids also include flavonols, flavones,
isoflavones, and anthocyanins; all of which contribute to the color of a
tea’s infusion and its taste.
Amino Acids
Tea leaves contain many amino
acids, the most abundant of which is theanine. In the tea field, sunlight
converts amino acids to polyphenols, and as such; shade grown tea contains more
amino acids than tea grown in direct sunlight. Some tea bushes are even
deliberately shaded for several weeks before harvest to enhance the tea’s amino
acid content. Theanine, more specifically L-Theanine is responsible for promoting alpha brain wave activity
which promotes relaxation.
Methylxanthines
Methylxanthines in tea include the
stimulant caffeine and two similar compounds: theobromine and theophylline.
Methylxanthines also contribute to a bitter taste in the tea infusion. Caffeine is a central nervous system stimulant of the methylxanthine
class. It is the world's most widely consumed psychoactive drug. Unlike many
other psychoactive substances, it is legal and unregulated in nearly all parts
of world.
Minerals
28 mineral elements have been found in the tea flush5. Compared to other plants, tea has a higher than average amount of: fluorine, manganese, arsenic, nickel, selenium, iodine, aluminum, and potassium5
28 mineral elements have been found in the tea flush5. Compared to other plants, tea has a higher than average amount of: fluorine, manganese, arsenic, nickel, selenium, iodine, aluminum, and potassium5
Enzymes
Polyphenol oxidase and peroxidase are the most important enzymes in tea leaves
Polyphenol oxidase and peroxidase are the most important enzymes in tea leaves
pigments :There
are two major groups of pigments in fresh tea leaves: chlorophylls and
carotenoids.
No comments:
Post a Comment