A Biochemical Storm in a Teacup – Science Behind Teacup

Though it is viewed by many to be an outdated stereotype of an age gone by, tea still has great importance in a society like the one that exists today in Britain. What brought home the dependence that the public has on the nectar was the news coverage of the 2005 London tube attacks, as well as the more recent riots in the capital.

In each case, there was a point when the respective news reporter would say that the shopkeepers/volunteers were bringing out blankets and cups of tea for those clearing up the damage and it brought a smile to my face. Not from any warm fuzzy feelings that one gets when viewing altruism take place in a society that prides itself on segregating each person but rather from seeing the vehemently denied trope being played once again.

That’s Britain for you: A nation where the solution for almost any problem can be solved using the appropriate application of tea.

Youth start smashing up small businesses all over the capital, laying waste to buildings that have stood for longer than they’ve been breathing? – The cheek of it! Fetch some Darjeeling and turn the hoses on those rapscallions.

Of course, if the situation becomes extremely serious, then the appropriate course of action would be to maybe think about bringing out the Earl Grey. Only in dire situations though. It’s reserved for when the Americans have their alert raised to red and all their nukes pointed at Clapham Common.

I can’t quite imagine what would be cause for anything but tea. Given the damage from the events mentioned and their complementary tea-based responses, one could extrapolate and hypothesize that it might take something on the scale of Armageddon to be cause for a coffee-based response.

That or another Adele album.

All joking aside though, tea remains one of those things that divides drinkers. Our MOCA challenge results show that on technique alone, there’s such diversity and subjectivity in preference.

What is tea?

In the same way that red and rosé wines are both manufactured from the same grape, all the different varieties of tea come from one plant, Camellia sinensis. Just as with wines, the different varieties and their stereotypical flavors come from the processing of the plant.

Black tea undergoes the most intensive of the processing whereas green tea receives hardly any, with Oolong tea existing halfway between that of black and green.

Anything not coming from the C.sinensis plant can be ignored when discussing tea. This does mean that I’m going to disregard herbal and fruit “tea” because they are not from the aforementioned plant and, quite frankly, if they’re to be considered tea then a butter sandwich should be considered haute cuisine.

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In any one single tea leaf, there exists an incredible variety of elements and compounds that are all intertwined when it comes to the chemical reaction that takes place during the leaf’s processing.

Nitrogenous molecules have a major role in the tea leaf’s composition, with  75% of all the nitrogen in the leaf coming from amino acids, many of which are unique to the tea leaf. The other 25% comes from the alkaloid caffeine present.

The leaf also contains carbohydrates, most of which are pectins, as well as very small proportions of sugars and starches. In addition to this, there are pigments derived from chlorophyll and vitamins B/C.

The inorganic components of the leaf are mainly found in salts in the cell sap and they include Calcium, Magnesium, Copper, Manganese, Iron, Sodium, and many others.

The most important parts of the leaf are the enzymes and the polyphenols, due to the hugely important role they play in the processing of the tea leaves.

Polyphenols and Processing

To many, the term polyphenol is a foreign one but it is not as intimidating or deadly as it sounds. In the tea leaf, polyphenols are a group of around thirty compounds that account for nearly 33% of the soluble matter in a fresh tea leaf.

The six main polyphenols in tea are shown above:  Catechin (C), Epicatechin (EC), Epicatechin gallate(ECG), Gallocatechin(GC), Epigallocatechin(EGC), Epigallocatechin gallate(EGCG).

The following process is dependent on the polyphenols shown and it is known as fermentation but this term implies the involvement of microorganisms when there is none. The name is somewhat of a misnomer as the aim of the process is to allow the leaves to absorb oxygen to further certain chemical reactions.

After the tea leaves have been picked by indigenous workers who were paid a pittance ( possibly a penny more than a pittance if the company employing them is Fair Trade, allowing customers to appease their guilt over being white and/or middle class), the leaves come to rest in the tea factory, sitting until they have become soft and limp due to water evaporation. It is now that the process that is incorrectly termed fermentation can begin.

The leaves are rolled to break down the membranes and bring the juices containing polyphenols in contact with the enzyme polyphenol oxidase which catalyzes the oxidation of the polyphenols via oxygen molecules in the atmosphere. This shows that the process is not one of fermentation but rather an enzymatic oxidation reaction.

Whatever the name is given, the product of this process, together with the other constituents listed above, accounts for the unique flavor and rich coloring of black and oolong teas.

After this process is completed, the tea contains two kinds of polyphenols – oxidized and unoxidized. The unoxidized polyphenols released in the beverage create the astringent, “puckery” taste associated with tea.

The unoxidized polyphenols cause the tea’s pungency, whilst the oxidized polyphenols give the tea its color and flavor. The higher the degree of oxidation, the more color and less pungency a tea has. Green tea, which does not undergo oxidation, has more unoxidized polyphenols and more of an astringent taste. Black tea has more color but less of a puckered taste.

The action of the enzyme-catalyzed oxidation process is eventually stopped by the heating and drying process that makes the tea leaves into what many in the western world are familiar with today. However, these compounds are still present in the dry leaves, waiting for the boiling water to be poured over the teabag to dissolve them.

Is green tea healthier?

Polyphenols and Processing of Tea

It’s commonplace to hear the adage “Green tea is healthier than other teas.”

Why is this thought? Well, it has something to do with free-radicals.

Free radicals are atoms, ions, or molecules with a single unpaired electron (which can be seen as a covalent bond just waiting to happen).  Any biological system creates free radicals as a by-product of life. Most reactions that occur in the body are ordered in specific ways for specific purposes. Free radicals, however, are highly reactive and therefore not very selective about what they react with.

They can initiate a chain reaction which – even at very low concentrations- can cause serious toxic effects in biological systems. This damage is a contributing factor in cancer, various chronic and degenerative diseases and also adds greatly to the aging process. This is why many “health products” constantly bombard the public with advertisements proclaiming their anti-oxidant properties.

The unoxidized polyphenols (which green tea has in much higher quantities than black/oolong) protect the system against the oxidation of lipids and suppress cancer growth by combining protons with the free radicals and stopping potential reactions. They are more effective free-radical scavengers than other antioxidants like Vitamins C and E, making them very good for human systems.

However, it should be remembered that the body has a maximum Total Antioxidant Capacity (TAC) which means that simply dumping tea and other antioxidant-rich items into your body won’t necessarily be beneficial.

Milk and lemon?

Milk and lemon Tea

Milk, sugar, and even lemon are frequent additions to black tea by the drinkers of the brew and to those accustomed to it, these additions seem only to add to the comfort of a cup of tea.

Can it be detrimental though?

A study carried out showed that the polyphenols in tea bind with a protein in milk known as casein. Therefore it is not completely insane for one to think that putting milk into black tea would cut down the effects of its polyphenols?

Not substantially, it seems.

Even in black tea, which has gone through the enzymatic oxidation process, about 30% of the polyphenols remain unoxidized and the milk combines initially with the 70% of oxidized polyphenols. The effect of this combination is to ease the harshness of the oxidized polyphenols to your stomach. So if you prefer the taste of black tea, milk is probably a good thing. However, if too much milk is added then the casein will move onto the unoxidized polyphenols when it’s done with the oxidized polyphenols.

At the end of it all, tea is a wonderful drink that has numerous psychological and physical benefits. It’s little wonder why it is a drink which is celebrated all over the world, from East to West.