Chemistry: A Complex Cup of Tea

Polyphenols and Amino Acids

Tea is well known for being packed full of delicious things, delicious aromas, tastes, and even chemical compounds!  It is in fact the chemical compounds that give tea their complex and diverse aromas and tastes and its mind+body effects, which are brought out and varied based on the different processing techniques.

Polyphenols are the most abundant compounds in steeped tea.  They carry with them the drying sensation on the tongue and a slight bitter flavor.  Polyphenols are most abundant in the fresh, tender leaves of the plant, the new growth.  Polyphenols are produced in the tea leaves from the reaction of amino acids and sunlight.  Therefore, shade grown tea leaves, like those turned into Gyokuro, have lesser levels of Polyphenols and more amino acids.  In this tea the light, savory Umami flavor is able to shine, opposed to the dark liquor produced by leaves high in Polyphenols.

What do Polyphenols do?

The most notable category of Polyphenols are called Flavonoids.  The  compounds that make up Flavonoids are flavanols, flavonoid, falvones, isoflavones, and anthocyanins.  Flavanols are the most abundant and are referred to as tannins or catechins.  Flavanols are noted for their antioxidants and effects on the tea liquor, which is turned dark with rich and robust flavors, like in Black tea.

As mentioned above, the Gyokuro tea of Japan has a strong Umami flavor.  This is due to its high levels of amino acids.  Umami is the term used for the sweet, savory flavors of brothy Green teas.  Teas like Gyokuro are shaded for weeks in order to increase the levels of amino acids in the leaves and the Umami flavor.  The amino acid abundant in tea leaves is called Theanine, which is known to promote alpha brain wave activity and the feeling of relaxation.  Theanine also balances out the negative effects of caffeine in the tea, such as jitteriness.  Instead of unchecked caffeine that results in crashes and cravings, Theanine works with caffeine to promote a stimulated relaxation or clam alertness.

 

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