Theanine is a characteristic non-protein Amino Acid of tea tree, which has only been reported in mushrooms and some camellias. Although there are 26 kinds of Amino Acids found and identified in tea leaves, theanine accounts for about 70% of the total free amino acids in new shoot bud leaves, while the theanine content in fresh leaves accounts for about 1~1% of the dry weight of tea leaves. 2%. Theanine has important physiological activities and pharmacological effects, so it has become one of the hot spots in the development and utilization of tea functional components by scholars at home and abroad in recent years.
Like other amino acids, naturally occurring theanine exists in the L-form, has a caramel aroma, and has a savory taste similar to monosodium glutamate, but has a much lower taste threshold than glutamine. Theanine is easily soluble in water, and the color reaction of ninhydrin is purple. D-theanine can be detected in green tea, black tea and oolong tea.
The research shows that in different seasons, the distribution of theanine in different parts of the tea tree has a certain regularity. The parts with the highest theanine content of the tea tree are the new shoots and fibrous roots, while the old stems and main lateral roots are the lowest; the annual change of theanine content is the spring tea tree. The content of theanine is higher than that of tea trees in autumn, while the content of theanine in summer is the lowest. Theanine is newly accumulated when the tea buds germinate in spring, and theanine is accumulated in the roots in autumn and winter.
Theanine has a caramel aroma and a fresh taste similar to monosodium glutamate. It is the main flavor substance of tea. The main reasons are:
First of all, theanine is the most abundant in tea trees, accounting for about 40%-60% of the total amino acids in tea trees, 1%-2% of the dry weight of tea leaves, and even 4% in some premium teas;
The second is that its taste threshold is only 0.06%, which is very low.
The last is because it has a high leaching rate in tea soup, as high as 80%. Therefore, the taste of theanine can be easily manifested in the tea soup, and it can also inhibit the bitterness and astringency caused by caffeine and catechin, and enhance the freshness and sweetness of the tea soup.
At present, theanine has been approved by the U.S. Food and Drug Administration (FDA) as a generally regarded as safe (GRAS) ingredient, and is widely used in the food and pharmaceutical industries as a health product or an additive. Since the discovery of theanine, with the deepening of the related research on theanine, the research on the pharmacological function of theanine has attracted more and more attention. According to research reports, theanine has the functions of relaxing the brain, improving concentration and learning ability, protecting nerves, improving immunity, lowering blood pressure, reducing the occurrence of cardiovascular and cerebrovascular diseases, reducing the accumulation of fat and weight gain, and anti-tumor. . In addition, tea contains caffeine equivalent to 2%-4% of dry weight, and studies have shown that theanine can antagonize the side effects caused by excessive caffeine. Its physiological functions mainly include the following aspects:
1. Theanine can reduce high blood pressure. After the rats were given theanine in the rat experiment, it was found that theanine could hinder the synthesis of serotonin in the rat brain and promote the decomposition of serotonin, so that the total content of serotonin in the brain was reduced, thereby reducing the high blood pressure. effect of blood pressure.
2. Theanine can protect nerve cells. Theanine is similar in structure to glutamic acid and can compete for the binding site of glutamic acid in cells, thereby inhibiting the death of nerve cells caused by excessive glutamate.
3. Theanine can interact with neurotransmitters to improve memory and learning ability. Experiments have shown that theanine can significantly increase the release of dopamine in the striatum of the brain, while increasing the content of tryptophan and reducing the release of serotonin. This interaction with neurotransmitters can improve memory and learning ability. .
4. Theanine can promote the human body to produce alpha waves to make the human body feel relaxed.
5. Theanine has biological synergistic effect on antitumor drugs. In in vitro experiments, the effect of theanine on the antitumor activity of doxorubicin was studied, and it was found that theanine could inhibit the exudation of doxorubicin from Ehrlich ascites tumor cells, and maintained doxorubicin in tumor tissue. concentration within.
6. Theanine can inhibit the infiltration of cancer cells.
7. Theanine has a weight loss effect.
Theanine can improve immunity and defense against viruses and menstrual syndrome.
Application of theanine at home and abroad
In 1998, at the International Health Food New Raw Materials Conference, theanine was rated as "the most worthy of developing new food materials".
So far, dozens of brands of health food in European countries have used theanine raw materials imported from Japan;
In the United States, as early as 1985, theanine was considered as a GRAS grade (that is, recognized as safe) Food Additive. At present, theanine has been directly developed into oral capsules and oral liquids in addition to traditional dosage forms. Products such as "bulk theanine powder", theanine aerosols, and "natural sleeping pills" are very popular in the US market. It is estimated that the annual sales of theanine products in the US market have reached 200-300 million US dollars, and the total market size is expected to reach more than 300-400 million US dollars. The hot sale of theanine in the international market has made the research of theanine a hot spot of widespread concern.
Based on a large number of studies on the properties of theanine, its advantages of good taste, safety, stability, and no toxic and side effects make it widely favored in Food Additives.
As a Food additive, theanine is not only soluble in water, but also has the characteristics of inhibiting bitterness and improving food flavor.
In addition, it can also be used as an additive for functional foods, because it can enhance the intensity of alpha waves in the brain, making it easy for people to feel relaxed and improve memory, so it is added to food, and it can also be developed. It is a functional food that relieves nervous tension, improves intelligence and plays a preventive role in Parkinson's disease, Alzheimer's disease, conduction nerve dysfunction and other diseases.
In terms of medicine, based on the significant physiological effects of theanine, it can also be developed as an auxiliary drug for lowering blood pressure and anti-tumor.
In other respects, the fresh smell of theanine can also be used in air fresheners; because it has an inhibitory effect on people's desire to smoke, it can also be used in smoking cessation and detoxification without causing emotional dependence; In cosmetics, it can also be used as a moisturizer or as a skin Moisturizing food. With the deepening of people's understanding of theanine, theanine will be widely used in more fields.
