Speaking of caffeine , do you think of coffee first?
In fact, there is a cold knowledge that is not too cold, that is, the content of caffeine in tea is higher than that in coffee.
As for why it is called caffeine and not theophylline? The reason is also very simple, just because caffeine was first discovered in coffee, and according to the convention of naming in the scientific community, "theophylline" can only find another way out.
What is "caffeine"?
Caffeine (Caffeine), also known as 1,3,7-trimethylxanthine, is an important plant purine base, which not only helps plants resist biological damage and pest invasion, but also To a certain extent, avoid other plants around to compete for nutrients. Among the plants that have been found to contain caffeine, tea has the highest content, and the caffeine in the leaves accounts for 2% to 4% of the dry weight. The content of caffeine in the seeds and fruits of the coffea plant is 0.4%~2.4%, and the content in the fruits of the cacao tree is 0.6%~0.8%.
1,3,7-trimethylxanthine
Caffeine is a crystalline substance with silky luster. As an important quality ingredient in tea, coffee and some functional beverages, caffeine has become one of the most widely consumed functional ingredients in the world.
The distribution of caffeine in tea plants 0
strongThe distribution of the leaf content is different. Almost every part of the tea plant contains caffeine, and more than 99% of the caffeine is present in the leaves. In addition to leaves, camellia, tea plant stems, tea seeds and roots also contain trace amounts of caffeine. Caffeine has the highest content in the young buds and leaves of the new shoots of tea plants.
Caffeine content in different tissues of tea tree seedlings (Yan Zhen, et al. Research progress on caffeine biometabolism in tea tree)
strong19span2 strong _span strong will affect the caffeine content in tea. The caffeine content of summer and autumn tea is significantly lower than that of spring tea. Therefore, caffeine can also be used as one of the important criteria for judging the quality of tea. At the same time, variety also has a certain impact on the caffeine content of tea plants. Conventional tea plant cultivars have higher caffeine content, but there are also some tea trees with lower content or no caffeine, such as cocoa tea The caffeine content is extremely low, and the "Hongyacha" found in southern Fujian does not contain caffeine.
Picture above: cocoa tea; Picture below: Hongyacha
In addition, different processing methods of will also change the alkali content of coffee.During the processing of green tea, white tea and oolong tea , the caffeine content remained basically stable or slightly decreased; while during the processing of black tea, the caffeine content of tea showed a significant increase.
The taste characteristics of caffeine
Caffeine is one of the main flavor substances of tea, with a low bitterness of 500 μmol/L. Temperature and pH will affect the bitterness intensity of caffeine and have a negative correlation. At room temperature 25 ℃, the bitterness intensity is the highest. EGCG is also a bitter and astringent ingredient in tea soup. The bitterness intensity of the mixture of caffeine and EGCG is higher than the bitterness presented by a single substance. The synergy between the taste substances gives the tea soup an unparalleled taste.
In addition to its own bitter taste, caffeine can also associate with theaflavin and thearubin through hydrogen bonds to form a complex, which is what we often say "cold after cold. ", which is conducive to the improvement of irritation, freshness and sweetness. In a certain concentration range, the combination of caffeine and tea polyphenol can promote the freshness of the tea soup, and it will turn into a bitter and astringent taste when excessive. Studies have shown that the threshold for the taste transition of caffeine is 3.8%~4.5%, and the threshold for the taste transition of tea polyphenols is 20%~24%.
physiological functions caffeine
1. reinforcement learning and memory
caffeine can stimulate the brain's central Nervous system,Prolong the awake time of the brain, keep the mind clear, sharp, and focus more concentrated. By taking caffeine, it can strengthen the learning and memory ability of animals. It is one of the first physiological functions of caffeine to be discovered. When taking proper amount of caffeine, caffeine can improve alertness, reduce fatigue, enhance recognition ability, shorten the reaction time of selection, improve instant memory, and improve the endurance and tolerance of simple and repetitive tasks, and improve work And the efficiency of learning. This also explains why people choose tea and coffee to refresh themselves when they are tired and tired at work.
Although caffeine is good, it should not be greedy. Adults who consume large amounts of caffeine for a long time or consume more than 1 g of caffeine at a time can cause "caffeine poisoning". The specific manifestations are addiction to caffeine or a series of physical and psychological adverse reactions such as nervousness, irritability, anxiety , insomnia, palpitations and so on. For pregnant women, caffeine can cause spontaneous abortion, premature delivery, and low birth weight. Therefore, the caffeine intake of special populations such as children and pregnant women must be strictly controlled.
Excessive intake of caffeine can cause symptoms such as insomnia, palpitations, etc.
2. Control weight and promote digestion , It has a weight loss effect and reduces fat accumulation. Studies have found that the intake of 100 mg of caffeine (about 1 cup of coffee) can accelerate the decomposition of fat and increase the body's metabolic rate by 3% to 4%. Caffeine can also stimulate the sympathetic nerve of , and increase the secretion of gastric juice. If you drink it properly after a meal, it will help digestion.A cup of tea is a good choice for digestion and relieving greasiness.
3. Anti-cancer function
can effectively reduce the risk of renal cancer in rats caused by the ingestion of caffeine. , epidermal growth factor caused malignant tumor cell metastasis, and can inhibit the growth of colon cancer cells. In addition to its direct anti-cancer effect, caffeine is often used as a chemotherapy synergist. Studies have confirmed that caffeine has a synergistic effect on breast cancer chemotherapy .
4. Diuretic and liver protection
Caffeine has a diuretic effect, it can promote the filtration rate of water in the urine, increase the filtration rate of the glomerular span1 The re-absorption of improves the discharge of harmful substances. In addition, caffeine can also promote the metabolism of the liver, excrete alcohol in the blood from the body, and reduce the harm of alcohol to people. Therefore, many people like to drink tea to hangover after drinking. In addition, caffeine can prevent liver cirrhosis and protect the liver.
5. Prevention and treatment of diabetes
span p1spanspanThe scholars of Harvard University found that long-term consumption of caffeine-containing coffee can significantly reduce the incidence of type 2 diabetes, while drinking decaffeinated coffee has no effect. Drinking green tea and coffee every day may help diabetic patients to prolong their life and improve their lives. Participants who drank 4 or more cups of green tea a day and 2 or more cups of coffee a day had even a 63% lower chance of death.
The combined effect of the intake of green tea and coffee on all-cause mortality in diabetic patients (Komorita Y, et al.)
_span2 strong span1 _span _span _strong19 1. Food industry
In addition to tea, coffee, chocolate and other beverages and foods that are rich in caffeine, caffeine can also be used as a natural additive to significantly improve the taste of food and beverages, and at the same time increase mental vitality. In order to stimulate consumer enthusiasm, more than 70% of beverages on the market are added with 0.02% caffeine, and some foods such as ice cream are also added.
2. Pharmaceutical industry
is used as a stimulant and a caffeine in medicine, as a stimulant in medicineIt is also widely used in clinical analgesia, hemostasis and other medical fields, and the market development prospects in the medical field are very broad.
3. Daily chemical industry
In the field of daily chemicals, caffeine can be used to develop weight-loss products and beauty skin care products to meet the needs of consumers, especially women.
Caffeine-added eye creams, essences and other beauty products
(picture from the Internet)
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