Today, May 21, we celebrate International Tea Day and for this reason, nutritionist Maria Carmen Japaz explains the most important aspects of this beverage:
Tea is defined as the infusion of treated and dried leaves of the camellia sinensis plant. Its origin is located in China and arrives belatedly to Europe through Dutch traders in the XVII century and it is not until the following century when it reaches a wide acceptance in England and its colonies, becoming the national drink.
There are basically 2 types of tea:
- Black tea is made from the leaves which, once picked, are dried and then left to ferment. This fermentation affects the phenolic compounds present in the leaves. These compounds are pigments that give the leaves a dark color and become more easily soluble.
- Green tea was the way it was consumed in ancient times in China. It is produced by drying the leaves at high temperature, thus inhibiting enzymatic activity and consequently fermentation. For this reason, the characteristics of green tea depend on the composition of the leaves as they are present in the plant and not on subsequent processes.
Currently there is a great diversity of teas on the market, some of which are semi-fermented in order to offer products with diverse organoleptic characteristics.
Caffeine content
The quantity of caffeine in tea is equal to that of coffee when expressed in dry substance; but to prepare a tea we use less quantity, therefore, in 1 cup of prepared beverage there will be less quantity of caffeine.
For many people the stimulating effect of caffeine causes insomnia, they can therefore resort to decaffeinated tea, which is obtained from the dried leaves of fermented black tea and then the caffeine is extracted through the action of solvents.
- 1 cup of coffee 60-80 mg of caffeine
- 1 cup of decaffeinated coffee 3-4 mg of caffeine
- 1 cup of tea 30-50mg of caffeine
- 1 cup of cocoa 10-40 mg of caffeine
- 1 cola soft drink 35-45 mg of caffeine
Nutritional value
Tea does not provide calories, and practically its nutritional value lies in its content of polyphenols with antioxidant properties.
Especially green tea contains a large amount of flavonoids or phenolic compounds: flavonols, catechin, epicatechin, epigalactocatechin, epicatechin gallate, epigallocatechin gallate, flavonol and kaempferol; all compounds with important antioxidant properties.
Potential adverse effects:
- Insomnia due to the effect of caffeine.
- Inhibition of the absorption of non-heme iron (iron present in foods of vegetable origin) which is only significant in vegetarian diets with a high consumption of tea; and provided that tea and food sources of non-heme iron are consumed together.
Infusions or herbal teas
These are herbal teas made from leaves, seeds, fruits and other parts of various plants, for example: chamomile, fennel, pennyroyal mint, lime blossom, valerian, etc.
A recommendation: Green tea
For people who are not sensitive to the effect of caffeine, it can be a stimulant and reduce the feeling of fatigue. It counteracts migraine, drowsiness and mental fatigue.
Tannins are responsible for its characteristic bitter taste and has an astringent effect, which is why it is used in people with diarrhea as well as black tea.
If there is one thing that characterizes green tea, it is its antioxidants; a wide variety of compounds that protect tissues from damage caused by free radicals. These compounds are not present in black tea, since they are lost during its elaboration process.
It is also rich in theobromine, which has a diuretic, vasodilating and relaxing action on smooth muscles (those of the organs and arteries).
Among the minerals, it is rich in fluorine and manganese.
Properties of green tea:
- Reduces LDL cholesterol levels (bad cholesterol) therefore, it is used in the prevention of cardiovascular diseases.
- By neutralizing free radicals through its antioxidant action, it protects cells from being damaged (cancer prevention).
- It delays the aging of the skin and internal organs.
- Regulates blood pressure, preventing hypertension.
- Strengthens the immune system.
- Due to its fluoride content it protects teeth from being attacked by bacteria.
How to prepare green tea:
- Use a heaping dessert spoonful of green tea per cup.
- The antioxidants in green tea are soluble in water, therefore, if we infuse for a long time (5-10 min) the tea leaves, we will get the antioxidants to migrate and concentrate in the water.
- Green tea should not be prepared with boiling water, otherwise its taste will be too bitter.
Varieties of green tea:
- Lung Ching: is the best known variety and means Dragon Well. It is the usual drink of monks who use it to clear the mind and relax. It has a golden color and sweet flavor.
- Bancha: it is extracted from the plant of the same name. It has a slight hay flavor.
- Gundpowder: it is very popular in Morocco. It is sweet and sour and is boiled with mint and sugar.
- Sencha: very popular in Japan, it has a yellowish color and tastes like vegetables.
- Matcha: highly appreciated by the Japanese for its refreshing power. It is the variety served in the tea ceremony.
- Pi Lo Chun: absorbs the aroma of fruits from the fruit trees growing around it.