Enviga – no weight loss there

Coca-Cola and Nestle who are joint producers of Enviga green tea soft drink have been advertising it as a weith loss, calorie burning product. Now, in a settlemant with 27 US states the companies have to pay $650 000 and relabel the drink. Any beverage labeled as a ‘calorie burner’ must clearly state that consuming it does not result in weight loss. According to Coca-Cola studies have shown that the combination of caffeine and the antioxidant EGCG cause calorie burning.

This is a good example of that consumers should be really altert and careful with what they buy. Apart from ‘weight loss claims’ one should be aware that most of the comercially availiable labeled as teas, iced teas or ‘containing anitoxidants’ really only contain an avrage of 0,1% of tea extract. Those products either hardly if at all have the same nutrition values as regular tea – what you are really buying is a soft drink and not tea.

 

What is decaf tea?

I think that many of us would like to drink tea all day long, dosing up on all those antioxidants, but the truth is that tea does have caffeine and drinking a lot of it especially in the evening can cause sleeping problems. At some point you might want to consider decaf tea. This was the case for me when I thought about decaf tea for the first time – and I wondered what it means for tea to be decaf, does it change the tea in any significant ways?

There are two ways in which tea can be decaffeinated. The first one uses a solvent called ethyl acetate and it allows about 30% of the polyphenols (antioxidants) to be retained. This method is cheaper, but also less beneficial for us as consumers. 

The second process is called effervescence and is more natural, using just water and carbon dioxide. Here 95% of polyphenols are retained, making this a more desired way of decaffeinating tea.

An alternative way to decaf tea yourself, which I mentioned in an earlier article is letting your tea steep for 30-40 seconds, pouring out the liquid and continue to steep the same tea leaves. The tea you pour off contains most of the caffeine, because it gets released in the beginning of the steeping. You can also choose naturally caffeine-free teas like rooibos or herbal infusions. You want to avoid bagged green tea, because it contains more caffeine then loose leaf and also you get less control of how much tea to brew. 

Since the three main substances in tea leaves (polyphenols, amino acids and caffeine) all affect the taste of the infusion, it is inevitable that the decaffeination process will alter the flavor.

Tea Chemistry

The chemical structure of tea can be generally divided into two parts – insoluble in water and soluble in water. The insoluble part contributes to the physical structure and appearance of tea and consists of crude fiber, cellulose, proteins, lignin, fats, chlorophyll and other pigments and starches.

The part of tea that we are mostly interested in is the soluble part, which contains all those health benefits that we like so much, but also defines the way tea will taste. This part consists of polyphenols to a large degree (commonly known as catechins also refereed to as tannin), amino acids (theanine), caffeine and minerals. Catechins are a type of antioxidants and can make up about 30% of the dry weight tea. Catechin content is higher in green and white tea, because black tea undergoes the oxidation process which reduces catechin content. Caffeine makes up about 3% of dry weight tea.

 

 

Different concentrations of compounds in tea are responsible for different characteristics in tea:

Polyphenols- astringency and bitterness
Amino Acids – sweetness and flavor
Caffeine- bitterness and briskness

Catechins

It’s because of catechins that tea is listed by research as one of the top foods to be consumed for better health and longer lifespan. There are four main catechin types found in tea EC, ECG, EGC and EGCG of which the last one is most potent.

Amino Acids

The amino acid L-theanine is characteristic only to tea plants and a few kinds of mushrooms. This substance provides the sweetness in tea. Leaves and buds collected early in the season have a higher concentration of theanine and are therefore sweeter in flavor.

Caffeine

Caffeine is a stimulant that affects our central nervous system and gives bitterness to the tea. Young tea leaves amd buds have a higher caffeine amount, but generally a cup a tea can contain 15 – 30mg of this substance.

How it works

Any substance that works in our as an antioxidant gives away an electron – this is the most important characteristic for antioxidants. Electrons like to be in pairs and substances with an uneven number of electrons can cause damage to our body – these are also known as free radicals. When an electron is donated by the antioxidant to the harmful substance is can be ‘calmed down’ and potential damage can be avoided. What also occurs is that the antioxidant after giving away the electron becomes a radical itself and has to be given an elecrton from a different type of antioxidant. The antioxidants work togather as a team and your body needs different kinds of antioxidants from rich sources like naturally grown foods, fruits, vegatables and tea in order to keep a balance.