Tanning agents give tea a distinctive astringent taste. Their average content
in a tea leaf ranges from 8% to 30%, being the main component of all substances contained in the tea solution. They are a complex mixture of tannin and catechins, polyphenols and their derivatives.
Caffeine in conjunction with tannins, as well tea catechins, have properties of vitamin P (bioflavonoids), which has capillary strengthening and hypotensive (pressure-reducing) effects, stabilizes collagen in vascular walls, and contributes to a better activity of vitamin C (ascorbic acid).
Due to tannin tea is the main supplier of vitamin P to the human body.
The amount of essential oils in tea is insignificant (0.006% of a dry tea leaf), but it’s thanks to them that we can enjoy the aroma of tea. Of course, the aroma is pleasant in itself, but the substances that cause us to feel it act in a certain way on our central nervous system (especially in the limbic system), creating a special emotional background.
During the manufacture of tea from fresh leaves part of the essential oils is destroyed, but part of them are recreated anew. That is why it is possible, using different processing techniques, to source teas with different flavours from the same plant.
The main tea alkaloid is caffeine, but in tea it is joined with tannins and forms theine, which acts more gently on the central nervous system, stimulating mental activity and intensifying the process of thinking. Its content in tea ranges from 1% to 4%.
To be continued…