The discovery of theanine originated from an in-depth exploration of tea ingredients. In 1949, Japanese scholar Yajiro Sakuto successfully extracted and separated this substance from Gyokuro tea and named it theanine.
This discovery caused quite a stir in the scientific community at the time. Before that, people’s research on tea mainly focused on tea polyphenols, caffeine and other ingredients, and the emergence of theanine opened up a new field for tea research.
Characteristics of Theanine
Structure and characteristics
Structurally, theanine is composed of a molecule of glutamic acid and a molecule of ethylamine connected by an amide bond. This unique structure gives theanine many special properties.
In terms of physical properties, theanine is a white needle-shaped crystal with a melting point of 217-218℃. It is soluble in water but insoluble in ethanol and ether. This property allows theanine to dissolve quickly during the tea soaking process, giving the tea a fresh taste.
In terms of chemical properties, theanine has the common properties of amino acids and can react with acids and alkalis. Theanine will undergo a hydrolysis reaction under the action of acid or alkali to produce glutamic acid and ethylamine.
Sources of Theanine
Theanine is not evenly distributed in tea trees, but has specific “favorite areas”. Studies have found that theanine is mainly distributed in the young and tender parts of tea trees, such as buds and young leaves, among which one bud and one leaf has the highest content. As the leaves mature, the content of theanine gradually decreases.
There are also significant differences in theanine content in different varieties of tea trees. According to measurements, the theanine content of Anji white tea can be as high as about 5% of the weight of dry tea, while the theanine content of general green tea is between 1% and 2%.
Season also has an important impact on the content of theanine. In spring, the temperature is low, the tea trees grow slowly, and the synthesis rate of theanine is greater than the decomposition rate.
Therefore, the theanine content in spring tea is higher; while in summer, the temperature is high, the tea trees grow rapidly, and the decomposition metabolism of theanine is accelerated, resulting in a relatively low theanine content.
Theanine’s multiple benefits
As a unique ingredient in tea, theanine plays a positive role in human health in many aspects. From the protection of the nervous system to the regulation of blood pressure, from the improvement of memory to the fight against tumors, the effects of theanine cover multiple dimensions of human health.
The guardian of the nervous system
Theanine performs well in protecting the nervous system. Studies have shown that theanine can inhibit the death of nerve cells caused by transient cerebral ischemia and has a significant protective effect on nerve cells.
Blood pressure regulator
The stability of blood pressure is crucial to human health, and theanine plays an important role in this regard. Through experiments on spontaneously hypertensive rats, it was found that the injection of theanine has a significant blood pressure-lowering effect.
Its mechanism of action is mainly achieved by affecting the peripheral nerves or vascular system, and this blood pressure-lowering effect is dose-dependent.
Memory booster
Theanine also performs well in improving learning and memory. The mechanism of theanine in improving memory may be related to its functions of scavenging free radicals and promoting central choline.
Tests on humans have also shown that theanine can enhance alpha waves in brain waves, thereby enhancing learning and memory. It is like injecting a powerful force into the brain’s memory system, allowing us to learn and remember new knowledge more easily.
Tumour “Fighter”
Theanine also plays a unique role in the fight against tumors. Experiments on rats with liver tumors have shown that theanine can assist in anti-tumor effects through multiple pathways.
Theanine helps maintain the metabolic balance of cells, keeps blood total cholesterol, low-density lipoprotein, atherogenic index, triglycerides, lipid peroxidation and other indicators at normal levels, reduces peroxidation stress in the body, and creates an environment that is not conducive to tumor growth.
Fatigue “Relief”
For people who exercise regularly or feel tired, theanine is a thoughtful “fatigue reliever”. Theanine has the effect of delaying exercise-induced fatigue.
Its mechanism may be related to the effects of theanine increasing the dopamine content in brain tissue and inhibiting the synthesis and release of 5-hydroxytryptamine, which allows us to recover energy faster after exercise and reduce fatigue.
Emotional Soother
In terms of mood regulation, theanine is like a gentle soother that can relieve depression and improve menstrual syndrome. Clinical trials on women have also proven that theanine can improve menstrual syndrome.
Most women experience mental and physical discomfort 3-10 days before menstruation, and the sedative effect of theanine can effectively relieve these symptoms, making women more comfortable and at ease during menstruation.
Application of Theanine
With the continuous deepening of theanine research, its unique properties and functions are gradually recognized by people, which has also led to theanine being widely used in many fields, from daily food to professional medical care, to the exploration of other fields. Theanine is bringing more possibilities to people’s lives with its unique charm.
Food industry
In the food industry, theanine has become a popular “new favorite” due to its unique flavor and health functions. It can be used as a functional additive to add unique value to food.
Theanine also has the magical effect of improving the flavor of food. It can reduce the bitter taste caused by caffeine and catechins, enhance the sweetness, and make the taste of food more mellow and delicious.
Medical and healthcare field
In the field of medicine and health care, theanine is widely used in the development of health products because it has multiple physiological activities, such as anti-oxidation, anti-inflammatory, neuroprotection, and mental regulation.
In terms of drug research and development, theanine also has potential application value. Studies have shown that theanine can assist in the treatment of some diseases, such as hypertension, depression, and neurodegenerative diseases.
Other fields
In addition to the food and medical health fields, theanine has also begun to actively explore other fields. In the field of daily chemical products, due to the antioxidant and moisturizing effects of theanine, it is used in the research and development of skin care products.
In oral care products, theanine may also play a role. It can inhibit the growth of bacteria in the mouth, keep the breath fresh, and bring consumers a healthier oral care experience.
In the chemical industry, the application of theanine is also gradually being developed. It can be used as a natural surfactant in the production of detergents, cleaners and other products.
Extraction and Synthesis of Theanine
Extraction process
There are many methods for extracting theanine from tea leaves, and each method has its own unique features. Precipitation is an earlier method, in which the copper carbonate precipitation method uses the property of theanine and basic copper carbonate to generate lavender columnar copper salt to separate theanine.
Alcohol precipitation is also a precipitation method. It uses the difference in solubility between theanine and other impurities in solvents such as water and ethanol to separate them. It is easy to operate.
A certain amount of anhydrous ethanol is added to the waste dry powder after extracting tea polyphenols and catechins or the crude theanine powder after preliminary purification. After standing, white matter is precipitated. The white matter is dried at a constant temperature of 75°C by centrifugation or suction filtration to obtain theanine crude product.
The ion exchange method uses the amphoteric electrolyte characteristics of theanine to achieve separation and purification through exchange adsorption. Strong acid cation exchange resin has a good adsorption effect on theanine.
Under certain conditions, theanine can be adsorbed by the resin and then eluted by a suitable eluent. This method is more selective for theanine, easy to elute, has fewer impurities in the eluent, and has high light transmittance, which ensures the stability of product quality.
Membrane separation, as an emerging green and energy-saving method, has received increasing attention in recent years. It uses the selective permeation principle of the membrane to separate and purify theanine extract.
Ultrafiltration membranes can remove macromolecular impurities, and reverse osmosis membranes can be used to concentrate theanine solution.
This method reduces the large amount of reagents required in traditional extraction processes and has the advantages of being eco-friendly, low energy consumption, high extraction purity, simple process, low production cost, and high separation efficiency.
Synthesis of Theanine
There are two main methods for the synthesis of theanine: chemical synthesis and biosynthesis. The chemical synthesis method is mainly the glutamic acid-ethylamine synthesis method, which dehydrates glutamic acid at room temperature into a cyclic lactam structure, and then controls certain conditions to allow ethylamine to combine with glutamic acid converted into a cyclic structure to form theanine.
This method is relatively simple to operate, low cost, and suitable for industrial production, but it also has some disadvantages, such as the raw materials are not easy to obtain, polluted, toxic, and difficult to purify.
The biosynthesis method mainly includes tea tree in vivo synthesis, microbial enzymatic synthesis, and cell culture. Theanine synthesized in the tea tree is directly synthesized by L-glutamic acid and ethylamine under the action of theanine synthase.
The microbial enzymatic synthesis method uses microbial fermentation to produce enzymes, and then uses enzyme extracts to produce theanine. The cell culture method uses explants such as tea tree stem tips to produce callus tissue, and uses callus tissue to produce theanine.
People who are suitable for theanine
People who are under great pressure and prone to anxiety: Theanine can promote the release of central neurotransmitters in the brain, help regulate emotions, relieve tension and anxiety, and relax the body and mind. Daily supplementation of theanine in this group of people can help improve their mental state.
People with poor sleep quality: Theanine can help people relax their body and mind, reduce the excitement of the brain, and have a certain improvement effect on sleep problems such as insomnia and dreaming caused by mental tension, etc., help improve sleep quality, and is suitable for people who have difficulty falling asleep and have shallow sleep.
People with low immunity: Theanine can regulate the human immune system, enhance the activity of immune cells, improve the body’s resistance, and help the body resist the invasion of external pathogens.
People who need to improve cognitive ability: Theanine can improve the brain’s cognitive ability and attention, enhance memory and learning ability, and help them complete tasks better.
People at risk of cardiovascular disease: Theanine helps regulate blood pressure and is beneficial to cardiovascular health.
People at high risk of neurodegenerative diseases: Theanine has a protective effect on nerve cells and may help prevent neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease.
Sports enthusiasts: Theanine can relieve sports fatigue, help sports enthusiasts recover faster, and improve recovery efficiency after exercise, so it is suitable for people who exercise regularly.
Generally speaking, most people can benefit from moderate intake of theanine, but if you are taking specific medications or have special health conditions, it is recommended to consult a doctor or professional health advisor before using theanine supplements.
The Prospects of Theanine
As people pay more and more attention to health, theanine, as a natural ingredient with multiple health functions, has a very broad market prospect.
In the field of food, theanine, as a safe and healthy additive, will continue to play an important role in sports drinks, snack foods and other products, bringing consumers more delicious and healthy choices.
In the field of medicine and health care, with the in-depth study of the pharmacological effects of theanine, it is expected to play a role in the prevention and treatment of more diseases and make greater contributions to human health. In the field of daily chemicals and chemicals, theanine will also have a broader application space due to its unique efficacy.
However, the development of theanine also faces some challenges. In terms of extraction and synthesis, it is necessary to further optimize the process, improve efficiency and reduce costs to meet the growing market demand.
In terms of quality control, it is necessary to establish more complete standards and testing methods to ensure the quality and safety of theanine products. In addition, it is necessary to strengthen the publicity and promotion of theanine and improve consumers’ awareness of its efficacy and application.
In the future, there are many directions to explore in the research and application of theanine. In terms of basic research, we can further study the mechanism of action of theanine in the body, including its interaction with other biomolecules and its regulatory mechanism on different physiological systems, which will provide a more solid theoretical basis for its application in the medical field.
In terms of applied research, we can develop more innovative products based on theanine, such as new health products, functional foods and personal care products. We can also explore the potential applications of theanine in agriculture, environmental protection and other fields to expand its application scope.
