When making tea, it is often seen that there is a layer of "foam" floating on the surface of the tea soup, what are these "foam"? Some people think that it is the residue of pesticides or impurities in the tea, which is a sign of poor quality tea. But in fact, the formation of foam in tea soup is mainly due to the presence of a substance called Tea Saponins. Scientific research shows that Tea Saponins has antibacterial, anti-inflammatory, analgesic and other effects, so it is not only harmless to the human body, but beneficial.

一．What is Tea Saponins?

Tea Saponins, also known as Saponins because of its aqueous solution and its ability to produce a persistent, soap-like solution foam when oscillated. Saponins exist widely in more than 90 families and 500 generas of plants in nature. These plants include the common oil crops such as soybeans and Camellia Oleifera, but also ginseng, codonopsis pilosula, paris polyphylla and other precious Chinese herbs such as liquorice, sea cucumber and pulsatilla. In addition, some Marine organisms such as starfish can also secrete saponins.

Tea saponin is a kind of natural glycoside compound in theaceae. It is a mixture of oleanane-type Pentacyclic Triterpenoid Saponin. The basic structure is composed of saponin, glycosome and organic acid. Tea saponin has the commonality of camellia saponins, it is a colorless and ashless fine columnar crystal with a melting point of 223~224°C, bitter and spicy, it can bubble and has hemolytic effect. The crystallization of tea saponin is insoluble in ethyl ether, chloroform, acetone benzene, petroleum ether and other solvents, also insoluble in cold water, anhydrous ethanol and anhydrous methanol, but slightly soluble in warm water, carbon disulfide and ethyl acetate, and easily soluble in aqueous methanol, aqueous ethanol, n-butanol and glacial acetic acid, acetic anhydride and pyridine, and its solubility increases significantly in dilute alkaline aqueous solution.

Tea saponin is distributed in the roots, stems, leaves and seeds of tea plants, but its molecular structure is different, resulting in different physical properties. In terms of content alone, the saponin content in tea seeds was the highest, but the content of tea saponin in different tea seeds is different.

The content of tea saponin in tea seeds, like other plant inclusions, is affected by the geographical location of tea plants, environmental conditions, tea tree type, variety, seed maturity, and even the regularity of fruit. The tea area of China is vast and the complex ecological conditions will have a profound impact on the content of tea seed saponin.

二．Application of Tea Saponin

Modern medical research has shown that tea saponin has the effects of hemolysis and fish toxicity, also has anti-insect bactericidal effect, anti-osmosis, anti-inflammatory, relieving cough, antalgic, anticancer and other pharmacological functions, and promoting plant growth effect. In addition, Tea Saponin also has good emulsification, dispersion, wetting, decontamination, foaming and other surface activities, it is a natural surfactant with excellent properties. Therefore, tea saponin is widely used in washing, wool spinning, knitting, medicine, daily chemical industry, construction industry and other fields.

1. Application in daily chemical industry

The tea seed cake has been used to soak water for washing and shampooing in ancient times, and it is generally believed that tea seed cake water can make hair soft and bright after washing, and can remove dandruff and relieve itching. In modern times, tea saponin, as a natural product, is a rare surfactant material in the daily chemical industry.

The surface activity of tea saponin can be used to make shampoo etc., which not only makes hair shiny and feels soft, but also is practically non-toxic, safe to use, and has the effect of nourishing hair and skin care, and also has anti-inflammatory, anti-itching, anti-dandruff effect and other pharmacological functions. As a matrix component, tea saponin can be used in sunscreen and anti-inflammatory skin creams, soaps, body washes, etc.

2. Application in medicine

Tea saponin has the effect of reducing phlegm and relieving cough, and can treat senile bronchitis and various edema. The developed tea seed syrup has obvious effect in treating senile chronic bronchitis. It is reported that tea saponin can be used as an anti-influenza drug, also in a variety of drugs or health drinks and foods.

3. Application in breeding industry

In shrimp culture, the hemolysis and fish toxicity effects of tea saponin can be used as a pond cleaning agent to kill harmful fish, but has no bad effect on shrimp, and saponin is not absorbed by the human stomach; Feed additives made from tea saponin are effective alternatives to antibiotics, which can reduce zoonotic diseases, make the whole breeding industry to a new level, and finally make people eat safe meat.

4. Application in other areas

In terms of pesticides, tea saponin can be used as wetting agent and suspension agent in solid pesticides, as synergist and spreading agent in cream pesticides, and can also be directly used as biopesticide. Tea saponin can also be used in foam drilling, foam drainage and so on.

To sum up, when tea drinkers see the "foam" on the surface of tea soup when making tea, it is not what pesticide residues or impurities in tea, but tea saponin, which is beneficial to human health.