The Role of Polyphenols in Tea: Health Benefits and Flavor Profiles

Polyphenols are natural compounds found abundantly in tea, contributing significantly to its health benefits and distinctive flavor. These compounds, primarily catechins, theaflavins, tannins, and flavonoids, are known for their potent antioxidant properties. Catechins, especially epigallocatechin gallate (EGCG), are abundant in green tea and are particularly celebrated for their ability to neutralize harmful free radicals in the body. Free radicals are unstable molecules that can cause cellular damage, leading to oxidative stress. This oxidative stress is linked to a range of chronic diseases, including cardiovascular diseases, cancer, and neurodegenerative disorders. By scavenging these free radicals, catechins help reduce oxidative stress, contributing to better overall health.

In black tea, theaflavins and thearubigins are more prominent due to the oxidation process during tea production. While green tea undergoes minimal oxidation, black tea undergoes a full oxidation process, which converts catechins into these larger, more complex polyphenols. Theaflavins, in particular, have been studied for their ability to improve cardiovascular health by enhancing endothelial function, reducing cholesterol levels, and preventing blood clots. Research also indicates that these compounds may help lower the risk of developing high blood pressure and other related conditions.

Polyphenols not only confer health benefits but also shape the sensory qualities of tea. Their presence affects both the taste and aroma, with tannins contributing to the characteristic astringency and bitterness of tea. The robust flavor of black tea and the subtler bitterness of green tea can be attributed to the different types of polyphenols present in each. Beyond their sensory appeal, polyphenols have anti-inflammatory properties that can help mitigate conditions such as arthritis, inflammatory bowel disease, and other chronic inflammatory conditions.

Furthermore, regular consumption of polyphenol-rich tea has been associated with improvements in metabolism. Some studies suggest that these compounds may assist in weight management by boosting fat oxidation and increasing energy expenditure, providing an additional incentive for regular tea consumption. In summary, polyphenols in tea offer an impressive array of health benefits while enhancing the overall sensory experience of the beverage.
The Role of Polyphenols in Tea: Health Benefits and Flavor Profiles

Decaffeination of tea by ethyl acetate processing

To be considered truly decaffeinated for labeling purpose, tea must contain no more than 0.4 percent of caffeine by dry weight.

The most common decaffeinating solvent is ethyl acetate, a substance that occurs naturally in some fruits and non-toxic component of tea. The ethyl acetate decaffeination process uses the Haco Method, which is similar to the one used for coffee. Chemically, ethyl acetate breaks down into ethanol and acetic acid.

In this process, tea leaves are bathed in water washed with ethyl acetate to remove the caffeine and then dried.

This process leaves a maximum carrier residue of 1 ppm or less, and a maximum caffeine residue of 0.08 percent, dry weight. The tea is 99.9 percent decaffeinated at the end of the process, and has an 8 percent maximum water content when leaving the factory. Decaffeinated Ceylon Black is processed in this manner.

However, ethyl acetate is very difficult to remove after the decaffeination process and can leave a chemical taste.
Decaffeination of tea by ethyl acetate processing

Decaffeinated tea

In General Tea from the Camellia Sinensis family contains from 1.6 percent caffeine in Formosa broken leaf type to 4 to 4.5 percent in most other types. By U.S. Food & Drug Administration standards, 97 percent of the 4.5 percent caffeine must be removed in order to label the tea decaffeinated.

Some packers label their teas 98 percent caffeine free. These teas, however, have never been decaffeinated but have a naturally low caffeine count.

Decaffeinated tea leaves unfortunately produce a flatter-tasting tea. Decaf tea also lacks the ‘aliveness’ and intensity of regularly processed tea.

Tea is decaffeinated by various methods. There are three processes used to decaffeinate tea: methylene chloride, ethyl acetate and carbon dioxide.

The latter two are the only two permitted in the United States. The use of methylene chloride on tea uses the same processing methods as ethyl acetate (see below) but is not allowed for import to the United States.

The most common decaffeinating solvent is ethyl acetate. Chemically, ethyl acetate breaks down into alcohol and acetic acid. Both these components are considered safe for use in decaffeinating by the FDA.

Carbon dioxide is a high pressure, super critical process. Unlike the other two processes mentioned, this process is considered natural and is more gentle to the tea leaves. It has the added advantage of retaining 90 percent of its polyphenols, the healthful antioxidants abundant in green tea.

The decaffeination technology affects the constituents drastically in case of ethyl acetate because besides caffeine most of the catechins and certain related compounds are also removed. Tea decaffeinated using ethyl acetate loses up to two thirds of its flavonoid content.
Decaffeinated tea 

Herbal teas

There is a number of herbal tea varieties, one of those are the flower tea. These teas are caffeine free alternatives and offer various benefits. Herbal tea contains no traditional tea but is made from one or a blend of more than one other plant.

Herbal teas are a natural solution for people who want to get the protective health benefits of herbs in their daily diet but don’t feel comfortable taking handfuls of herbs as capsules, and rarely use more than the standard herbs like garlic and basil for cooking.

Herbal teas are obtained by infusion of fresh or dry plant material. Popular traditional herbal teas are made from Roselle, chrysanthemum, safflower, and bael fruit.

The most famous herbal teas
*Carnation flower tea – the tea is said to restore the energy of the body and also considered great for relaxing.

*Chamomile – floral tea to help the drinker unwind at night. It eases stomachaches, soothers nerves and lulls the drinker onto0 sleep.

*Chrysanthemum herbal tea - it is famous cooling tea infusion. It has a subtle sweetness and is highly refreshing.

*St, John’s wort – for treatment of mild to moderate depression. Has been used for its sedative, anti-inflammatory, anxiolitic and astringent qualities.

*Jasmine bud flower

*Wild New York Ginseng

*Honeybush tea – it is a pleasant way to keep the body well hydrated with fluids. The tea is very rich in antioxidants.

Herbal teas have no additives, preservatives or dyes. They aren’t sweetened with sugar or sugar substitutes and they’re not mixed with other ingredients that could compromise the herbs effect.
Herbal teas 

Drinking tea help burning calories

A number of scientists are interested in researching tea’s potential in addressing obesity. Green tea is highly enzymes-active to help burning calories.

It consumption leads to significant increase in calories burning and decrease in body weight and a decrease in waist circumference, all while producing no real change in heart rate or blood pressure.

In one study, metabolic rate was increased by an average of 266 calories per day, which means the person could lose approximately 1 pound every 2 weeks simply by drinking 8 to 10 cups of tea.

Green tea functions by using up energy, up to four percent. Scientists have attributed this to the high levels of catechins available in this tea.

Research also shows that epigallocatechin gallate or EGCG compounds in green tea is better beverage for weight loss.

In the beginning of the 21st century, Suntory Ltd, Japanese Company famous for its drink and beverage conducted a randomized cross over study and found that consuming full strength oolong tea increased energy expenditure which meant more burned calories per day.
Drinking tea help burning calories

Drink black tea saves arteries

Black teas contain significant amounts of antioxidants, which is why they reduce risk of heart disease and stroke.

Free radicals are responsible for certain chronic disease such as heart attack, coronary artery disease, stroke, and hypertension.

The antioxidants inhibit many oxidation reactions caused by free radicals, thereby preventing or delaying damage to cells and tissues.

Drinking black tea helps prevent deadly clogging of arteries and reverses poor arterial functioning that can trigger heart attacks and strokes, major new studies have found.

Tea is a rich source of many antioxidants. Within thirty minutes after drinking a cup of brewed tea, blood levels of tea’s antioxidants rise by 40 to 50 percent and may last for up to eighty minutes.

One study 1993 published in Lancet by Dutch researchers found that dietary antioxidants reduce the risk of heart attack among the residents of Zutphen, a city in the Netherlands. Men who consumed the most fruit and vegetables all rich in antioxidants had the lowest heart attack risk.

In different a large 10-year study in the Netherlands, men who consumed the amount of antioxidants called "catechins" found in three cups of black tea were 50% less likely to die of ischemic heart disease, caused by narrowed clogged arteries, than were men who consumed only the catechins in half a cup of tea.

Black tea contains various antioxidants including quercetin and catechins that can reduce the risk of coronary artery disease and stroke significantly.

In one test, by the Boston University School of Medicine, had heart patients drink either plain water or four cups of black tea daily. In a month, impaired blood vessel functioning (a risk factor for heart attack and strokes) improved about 50% in the tea drinkers.

The cardiovascular and anti-cancer benefits are substantially reduced if milk is added to the tea, a practice all too common in England, Canada, Australia and New Zealand.
Drink black tea saves arteries

Health benefits of Tea

Human beings have a long history of the tea plants cultivation and tea drinking. With excellence in unique and attractive colors, flavor, taste and numerous health benefits, tea has increased its acceptance universally by attracting attention of consumers from all over the world.

The tea drink daily in Japan is now touted as one of the healthiest drinks in the world.

Tea's active ingredients are caffeine in combination with the tannin that gives it its pungency and much of its aroma and flavor which essential oils also enhance.

Caffeine component in tea, helps to dispel drowsiness and lassitude. One cup of tea drunk during work will clear the head and refresh both body and mind.

The scientists' tests showed a cup of tea gives both an immediate and a delayed lift without secondary depressing effects later on. They agreed tea is a good agent for relieving fatigue and aids clearness of thought and digestion alike.

Common green tea and black tea leaves consist about 25-30% flavonoids, while the primary sources of polyphenols in green tea are catechins and flavones.

These flavonoids are produced via the shikimic and acetate-malonate biosynthetic pathways, characterized by their C6-C3-C6 skeletal structure corresponding to 2-phenyl-substitued benzypyrans and pyrones.

Flavonoids are natural vitamin-like compounds. They make blood cells called platelets less prone to clotting, and act as antioxidants, countering the artery-damaging potential of highly reactive free radical chemicals. Catechins reduce ‘bad cholesterol’ or low density lipoprotein cholesterol (LDL) in the blood, thereby preventing hardening of the arteries and the formation of blood clots.

In one study, men with a high flavonoids intake had a 73 percent lower risk of stroke during 15 years of follow-up, compared with men with a low intake of flavonoids. The men in the study got about 70 percent of their flavonoids from drinking black tea.

Other research shows that tea bolsters the heart’s resistance to cardiovascular disease, prevents dental cavities, lengthens a tea drinkers’ life span, detoxifies the body and boosts immune function.

Tea also helps prevent tooth decay in several ways. It contains a solid dose of fluoride and works better than the antibiotic tetracycline. According to researchers at the Tokyo Dental College, it fights the kinds of bacteria in the mouth that cause gum disease and the eventual loss of the teeth. It also kills the greatest cavity-causing bacteria in the mouth, Streptococcus mutans.

Some of the most exciting research involves the link between tea and the prevention of cancer. Additionally, green tea eases the adverse effects of cancer therapies, such as radiation and chemotherapy.

Properties in green and black tea called antioxidants are thought to be active agents against skin cancer. In the past 10 to 15 years, a growing body of research has shown that foods and vitamins with a strong anti-oxidant effect may reduce the risk of many diseases, including cancer and aging.

The rich presence of catechin polyphenols, particularly epigallocatechin gallate or EGCG is the reason why green tea has so much health benefits. A powerful antioxidant, EGCG can not only inhibit cancer causing agents in cell growth but can also destroy them without harming healthy cells.

Health benefits of Tea

Chinese tea

Tea has played an important role in the social and cultural fabric of life around the world for thousands of years.

It is enjoyed for its health benefits and its contribution to living a better, simpler and aesthetically appealing life.

It is said that tea was discovered about 3000 BC by the legendary ruler Shennong. He sampled numerous herbs in order to find out their possible uses as food or medicine for his people.

In third century the celebrated surgeon Hua Tuo, originator of anesthesia, is reported as saying that tea drinking increased concentration and alertness.

In ancients, times, many Chinese, including emperors and common people alike, were captivated by its unique fragrance and aesthetic experience.

Tea drinking in China gradually spread from the south to the north. Widespread tea drinking began during the Tang dynasty, sometime between the eight and tenth centuries. It then extended from China to her neighboring countries.

Tea is always offered immediately to a guest in a Chinese home. Serving a cup of tea is more than a matter of mere politeness, it is a symbol of togetherness, a sharing of something enjoyable and a way of showing respect to visitors.

The plant which produces the common kinds of tea in commerce is the Thea chinensis, of which there are a number of more or less constant varieties so that several botanists have made three distinct species, viz, Thea viridis, Thea bohea and Thea stricta.

Fresh tea leaves are not aromatic. The tea fragrance emerges after the leaves are cured slowly under low heat. The cured tea leaves are either black or green depending on whether the leaves are fermented or unfermented.
Chinese tea