Coffee tree is a small evergreen tree of Rubiaceae. Coffee for daily drinking is made of coffee beans with various cookers. Coffee beans refer to nuts in the fruit of coffee trees, which are baked in an appropriate way and have a bitter taste.
Should I give up coffee?
have
Studies have shown that premature mortality, the incidence of type II diabetes and the reduction of some cancers are all related to drinking coffee. The active ingredients in coffee can help alleviate oxidative stress, that is, the imbalance between free radicals and antioxidants.
Balance phenomenon. Caffeic acid in coffee can also improve the utilization rate of blood sugar by muscles. In addition, it also contains ingredients that promote the immune system and anti-inflammation. Systematic summary of research results is the most powerful method to measure scientific evidence.
So you never have to give up coffee again.
Caffeine alcohol has more anticancer effects.
Coffee contains coffee bean alcohol and caffeic alcohol, which has anti-cancer and anti-inflammatory effects. Coffee can up-regulate the anti-toxic biochemical process in the liver and protect the body from aflatoxin and other carcinogens.
Coffee can reduce the incidence of diabetes.
Coffee contains chlorogenic acid, which has been proved to promote glucose metabolism, improve insulin sensitivity, improve the utilization rate of blood sugar in muscles, and thus reduce the risk of diabetes.
Related terms:
Tea, cocoa and cola
Content arrangement: text
Chinese name
coffee
Foreign name
coffee
The origin of coffee tree
Ethiopia
be used for
Wake up, cheer up, etc.
application area
Friends get together, work overtime, chat and drink, etc.
spell
Kafi
kind
Cappuccino, black coffee, latte
Powdering
caffeine
side effect
Headache, sleep disorder, osteoporosis
match
Milk, sugar
catalogue
1 history
Two-component efficacy
raw material
efficacy
3 classification
4 purchase guide
5 China development
6 ways to drink coffee
Equipment use
Drinking instructions
Related nouns
Drinking guide
Disadvantaged population
Drinking taboo
7 pros and cons analysis
The benefits of coffee
Disadvantages of coffee
Coffee and health
Coffee addiction problem
1 History Editor
Coffee trees are native to the plateau area in southwest Ethiopia, Africa. It is said that more than a thousand years ago, a shepherd found that sheep ate a plant, became very excited and lively, and then discovered coffee. It is also said that a coffee forest was accidentally burned by wildfire, and the smell of barbecue coffee attracted the attention of the surrounding residents.
Local aborigines often grind the fruit of coffee tree, then mix it with animal fat and knead it into many spherical balls. These indigenous tribes regard these coffee balls as precious food for soldiers who are about to go out. It was not until 1 1 century or so that people began to use brewed coffee as a drink. /kloc-In the 3rd century, Ethiopian troops invaded Yemen and brought coffee to the Arab world. Because Islam forbids believers to drink alcohol, some religious people think that this kind of drink stimulates the nerves and violates the teachings. There was a time when coffee shops were banned and closed, but the Sultan of Egypt thought that coffee did not violate the teachings, so the ban was lifted and coffee drinks quickly became popular in the Arab region. The word coffee comes from Arabic Qahwa, which means "plant drink", and later spread to Turkey, becoming the source of this word in European languages. Arabs have also gradually improved the cultivation and production methods of coffee.
/kloc-the cultivation and production of coffee in the 0/7th century has always been monopolized by Arabs. It was mainly used in medicine and religion at that time. Doctors and monks all admit that coffee has the functions of refreshing, refreshing, invigorating stomach, strengthening body and stopping bleeding. /kloc-At the beginning of the 0/5th century, there were documents about the use of coffee. During this period, coffee was integrated into religious ceremonies and appeared as a daily drink among the people. Coffee became an important social drink at that time because Islam prohibited drinking.
1570, the Turkish army besieged Vienna and failed to retreat. Someone found a bag of black seeds in the barracks of the Turkish army, and no one knew what it was. A Polish man who once lived in Turkey took this bag of coffee and opened his first coffee shop in Vienna. /kloc-At the end of 0/6, coffee was introduced to Europe on a large scale through Italy in the name of "Islamic wine". It is said that at that time, some Catholics thought coffee was a "devil's drink" and encouraged Pope Clemens VIII to ban it, but the Pope thought it was safe to drink after tasting it and blessed it, so coffee gradually became popular in Europe.
At first, coffee was very expensive in Europe, and only nobles could drink it. Coffee is even called "black gold". Until 1690, a Dutch captain sailed to Yemen and got several coffee seedlings, which were successfully planted in Indonesia. 1727 the wife of a diplomat in Guyana, the Netherlands, gave some coffee seeds to a Spaniard in Brazil, where he tried planting and achieved good results. Brazil's climate is very suitable for coffee growth, and coffee has spread rapidly in South America since then. Due to mass production, the price of coffee has dropped, and coffee has become an important beverage for Europeans.
Kenya AA(8 sheets)
2-component efficacy editing
raw material
Name function
Caffeine has a particularly strong bitter taste and stimulates the central nervous system, heart and respiratory system. Moderate caffeine can also reduce muscle fatigue and promote the secretion of digestive juice. Because it can promote renal function, it has diuretic effect and helps the body discharge excess sodium ions. But too much intake can lead to caffeine poisoning.
After boiling, tannic acid will decompose into wood vinegar, so the taste of coffee cooked for too long will become worse.
The most important fats are acidic fats and volatile fats.
Acidic fat, that is, fat contains acid, and its strength will vary with different types of coffee.
Volatile fat is the main source of coffee aroma, and it is a substance that emits about 40 kinds of aroma.
The main source of heat in protein is not high. Protein at the end of coffee will not dissolve out when making coffee, so the intake is limited.
Raw beans of sugar coffee contain about 8% sugar. After baking, most of the sugar will be converted into caramel, which will turn coffee brown and combine with tannic acid to produce sweetness.
The fiber of raw beans will carbonize after baking and combine with caramel to form the color of coffee.
Minerals contain a small amount of lime, iron, phosphorus, sodium carbonate and so on.
Table of nutritional components of coffee
The nutritional components of coffee beans per100g are shown in the following table.
moisture
1.2g
protein
1.6 g
fat
16g
carbohydrate
1.7 g
cellulose
9g
ash
1.2g
calcium (Ca)
120mg
phosphorus (P)
170 mg
iron
42 mg
natrium
3 mg
vitamin B2
1. 12g
nicotinic acid
1.5 mg
caffeine
1.3g
tannic acid
8g
Harald Coffee (5 pieces)
efficacy
Efficacy pharmacology researcher/organization
Drinking coffee after a hangover can quickly oxidize acetaldehyde converted by alcohol and decompose it into water and carbon dioxide to be excreted;
Diuretic and dehumidifying caffeine can promote renal function, expel excess sodium ions from the body, increase urination, improve bloating and edema, and help to lose weight. Black coffee is more diuretic.
Coffee for relieving constipation can promote metabolic function and activate digestive organs, which has a great effect on constipation.
improve
liver function
The results show that patients with chronic liver diseases such as hepatitis or cirrhosis can improve their liver function by drinking more than one cup of drip coffee every day. Japanese osaka city university Research Group
Caffeine can stimulate sympathetic nerve, stimulate gastrointestinal secretion of gastric acid, promote digestion, prevent abdominal distension and gastroptosis, and promote gastrointestinal hormones and peristalsis hormones, thus quickly relieving constipation.
Calming wind and relieving spasm coffee can increase high-density cholesterol, accelerate the metabolism of bad cholesterol, reduce coronary atherosclerosis and reduce the probability of stroke.
A cup of black coffee after a meal can effectively whiten the skin. Black coffee can also promote cardiovascular circulation.
Stop hard work
Tubular disease
People with low blood pressure can get better by drinking a cup of black coffee every day. In the process of brewing coffee at high temperature, it will also produce an antioxidant compound, which is helpful for anti-cancer, anti-aging and even prevention of cardiovascular diseases, and can be comparable to fruits and vegetables.
Caffeine is a mild stimulant, which can improve the sensitivity and attention of the human body, accelerate the metabolism of the human body, improve the mental state and physical quality of the human body, and thus eliminate fatigue.
Prevention of gallstones For caffeinated coffee, it can stimulate gallbladder contraction and reduce cholesterol which is easy to form gallstones in bile. The study found that men who drink two or three cups of coffee a day have a lower risk of gallstones than 40%. Researchers at Harvard University in the United States.
Preventable
radiation damage
This conclusion was obtained in mouse experiments, and it can be applied to humans. Baba's Indian atomic researcher
Experiments that affect mood show that the average person's intake of 300 mg (about 3 cups of brewed coffee) a day will have a good effect on a person's alertness and mood.
Bathing with coffee powder is a kind of hyperthermia, which has the function of losing weight.
3 classified editing
There are two kinds of coffee trees with important economic value: Arabica and Robusta.
Arabica coffee grows best at high altitudes. Its flavor is much more delicate than other coffees, and the caffeine content only accounts for 65,438+0% of the total weight of coffee.
Robusta coffee has mellow taste, strong resistance to pests and diseases, and high yield per plant. This kind of coffee grows at low altitude and tastes bitter.
4 buying guide editor
No matter what kind of coffee, freshness is an important factor affecting the quality. When shopping, grab one or two.
Mocha Coffee (5 pieces)
Chew a coffee bean in your mouth. If it is crisp and audible, it means that the coffee beans are not wet, and the coffee beans with fragrant lips and teeth are top grade, but it is best to pinch them with your hands to see if they feel solid. Never buy empty coffee.
Freshly fried coffee beans are not suitable for immediate drinking. Generally speaking, the best drinking period of coffee is one week after frying, when the coffee is freshest and has the best aroma and taste.
In addition, the purity of coffee beans is another consideration. Experts choose coffee, not necessarily by particle size, but by grabbing a handful of single coffee beans, about dozens.
Take a look at whether the color of each single bean is consistent and the particle size and shape are similar, so as to avoid buying inferior products disguised as mixed beans. But if it is a comprehensive bean, it is normal to have different sizes and colors. Heavy firepower and medium depth
Roasting will make coffee beans oil, but if lightly roasted coffee beans oil, it means that they have deteriorated, which not only reduces the mellow degree, but also leads to astringency and sour taste. In short, pay attention to the freshness, aroma and taste of coffee when purchasing.
It smells old.
5 China Development Editor
In late March of 20 14, the coffee planting area and output accounted for more than 99% of the whole country.
Mantinin Island, Sumatra (6 photos)
In the southern province, the coffee harvest is coming to an end. Affected by the international market, after more than two years of "price winter", the purchase price of coffee beans soared in 20 14, from per kilogram 13 yuan to 25 yuan.
Although soaring prices stimulated market confidence, during the 20 13 to 20 14 cropping season, the coffee production in China decreased from 80,000 tons in the previous cropping season to less than 60,000 tons. In the absence of large leading coffee enterprises and local brands, the pressure of reducing production makes it more urgent for China's coffee industry to "break through" from the origin of raw materials.
According to the survey, the coffee planting area in Yunnan increased from more than 300,000 mu in 2008 to more than 2065,438+04/kloc-0.4 million mu, and the output increased from about 30,000 tons in 2065,438+03 to more than 80,000 tons, accounting for more than 99% of the national coffee planting area and output, making it the largest coffee producing area in China.
According to coffee industry insiders, the price trend of Yunnan coffee in recent 20 years is almost once every 10 year.
Luwak Coffee (7)
Price cycle. In 20 10, the price of coffee in Yunnan reached 4 1 yuan per kilogram, a record high. From 20 12 to the beginning of 20 14, influenced by the drop in international coffee futures prices, the price was as low as per kilogram 13 yuan, and the coffee planting industry entered the "price winter" for two consecutive years.
20 14, 1 At the end of the year, with the rebound of international coffee futures prices, Yunnan coffee prices also rose rapidly. "In the past February, the international coffee price created the biggest monthly increase in 20 years, from165438+ 1 14 cents per pound on October 28th to 180 cents per pound on February 28th."
There are three reasons for the rapid rise in coffee prices: First, the climate in Brazil, the world's largest coffee producer, has been dry since the end of last year, which is expected to affect coffee production; Second, some coffee producing countries in Central and South America are affected by coffee rust, and coffee production is expected to decrease; Third, coffee futures have been in a long-term downturn, and coffee futures speculators intend to raise the price of coffee and activate the coffee futures market.
"The coffee harvest of 20 14 is coming to an end, but the coffee production in the province is less than 60,000 tons. The output of Pu 'er tea has also dropped by at least 30% on the basis of last year. "Despite the soaring purchase price, the sharp drop in coffee production has cast a shadow over the coffee planting industry in China.
Since 20 14, Nestle and Starbucks have increased their efforts to develop raw material producing areas in Yunnan, and Yunnan small coffee has also been sold to more than 20 countries and regions such as Europe, America, Japan and South Korea, but overall, Yunnan coffee industry is still in its infancy, and its "breakthrough" is not optimistic.
At present, China's coffee deep processing industry lacks large-scale comprehensive leading enterprises, and there are only a handful of local coffee brands, which have not played a leading role in market share and market evaluation at home and abroad. [ 1]
According to an online survey, 47% netizens like to drink instant coffee, while 72% netizens value the taste of coffee most. China people's habit of drinking coffee may have started after 1990s, and now many city people have become dependent on coffee. Although the annual consumption of coffee in China is only 200,000 tons, the per capita consumption is increasing at a rate of 30%, and it is expected to become the most potential coffee consumer in the world.
Zhong, vice president of China Coffee and Coffee Beverage Professional Committee, said in an interview: "Relatively speaking, the proportion of people who drink pure coffee in China is not high. They usually choose to add a coffee partner or drink coffee directly. " The investigation results of Lianhe Zaobao on coffee consumers in China market are as follows: [2]
Select the reference factor ratio of coffee.
Choice tendency
Someone's taste
brand
efficacy
price
Crowd proportion
72%
15%
8%
2%
Coffee habit survey
Choice tendency
Drink coffee often.
Never drink coffee.
Instant Coffee
Freshly Ground Coffee
Not picky about drinking coffee
Crowd proportion
65%
2%
47%
Thirty percent
23%
Gasoline (fuel)
lock
[Qingyou]
This entry is reviewed by the project of sorting out and applying scientific entries of "Popular Science China".
steam
The English name of the oil is gasoline (USA)/ gasoline (UK). The oil is transparent and flammable, with a distillation range of 30℃~ 220℃. The main components are C5 ~ C 12 aliphatic hydrocarbons and naphthenes.
And a certain amount of aromatic hydrocarbon. Gasoline has a high octane number (anti-knock combustion performance), which can be divided into four grades: 90, 93, 95 and 97. Gasoline is a straight-run gasoline group refined from petroleum.
Different gasoline components, such as FCC gasoline components and catalytic reforming gasoline components, are refined and blended with high octane number components, which are mainly used as fuels for automobile ignition internal combustion engines. [ 1]
Chinese name
petrol
Foreign name
petrol
density
0.70-0.78g/cm^3
calorific value
44,000 kJ/kg
safe
tinder
colour
Yellow transparent
Gas smell
fragrance
catalogue
Evolution of 1
Physical and chemical properties
3 preparation
4-purpose classification
Five important characteristics
evaporate
Blast resistance
stability
corrosivity
safe
6 gasoline brand
7 ethanol gasoline
8 environmental impact
health hazard
Toxicological data and environmental behavior
9 environmental standards
10 product standard
1 1 first aid
Emergency treatment of leakage
protective measure
Emergency treatment
Evolution of 1
petrol
/kloc-in the 0/9th century, people didn't realize the importance of gasoline. At that time, kerosene was widely used for lighting. Refining at that time relied on simple distillation.
Process, separation of petroleum components with different boiling points. Kerosene has a high boiling point and is safe to use when igniting. It has become the main product of crude oil refining, while gasoline and other components are usually burned as fuel. On 19.
In the middle and late 20th century, internal combustion engines using gasoline were successfully manufactured.
1886 gasoline engine runs successfully as automobile power, so the importance of gasoline is increasing day by day. But only 20% gasoline can be extracted from crude oil by distillation. 19 1 1 year, solved by American standard oil company.
In order to solve the problem of low gasoline yield, the thermal cracking process invented by William Burton and Robert Humphries was used to crack heavy gas oil into light gasoline and other fractions, which improved the gasoline yield as a whole. The thermal cracking process was authorized by American patent in 19 13. The subsequent catalytic cracking process further improved the gasoline yield and higher octane number than the thermal cracking process.
Physical and chemical properties
Gasoline is a colorless to yellowish flowable liquid at room temperature, which is insoluble in water and flammable. When the distillation range is 30 ~ 220℃ and the gas content is 74 ~ 123g/m3, it will explode in case of fire. The calorific value of gasoline is about 44000 kJ/kg (the calorific value of fuel refers to the heat generated after 1kg of fuel is completely burned). Physical and chemical properties are as follows:
Chemical formula Hydrocarbons (hydrocarbons) contain a mixture of five to twelve carbons.
Water soluble and water insoluble.
The density is 0.70-0.78g/cm3.
Transparent appearance
Aroma
Safety instructions flammable.
The calorific value is 44000 kJ/kg.
3 preparation
steam
Petroleum is made from crude oil fractionation and heavy distillation. In the process of crude oil processing, distillation, catalytic cracking, thermal cracking, hydrocracking, catalytic reforming and alkylation units all produce gasoline components with different octane numbers, such as straight-run gasoline.
The octane number is low, so it cannot be used as engine fuel alone; In addition, the sulfur content of impurities is also different, so it is necessary to desulfurize and refine the gasoline components with high sulfur content, then blend the above gasoline components and add high octane number if necessary.
Alkanes are divided into groups, and finally gasoline products that meet the national standards are obtained.
4-purpose classification
Gasoline is one of the most commonly used light petroleum products and an important fuel for engines.
According to the manufacturing process, gasoline components can be divided into straight-run gasoline, thermal cracking gasoline (coking gasoline), catalytic cracking gasoline, catalytic reforming gasoline, superimposed gasoline, hydrocracking gasoline, alkylated gasoline and synthetic gasoline.
Gasoline products can be divided into aviation gasoline, automobile gasoline and solvent gasoline according to their uses. The first two kinds are mainly used as fuels for gasoline engines, which are widely used in automobiles, motorcycles, speedboats, helicopters, agricultural and forestry planes and so on. Solvent gasoline is used to produce synthetic rubber, paint, grease and perfume. Gasoline components can also dissolve oil stains and other water-insoluble substances, and play a role in cleaning oil stains; As an organic solution, the gasoline component can also be used as an extractant.
Five important characteristics
The important characteristics of gasoline are evaporation, antiknock, stability, safety and corrosiveness.
evaporate
Refers to the difficulty of gasoline evaporation in carburetor. It has an important influence on engine starting, warming-up, acceleration, gas resistance and fuel consumption. Comprehensive evaluation of gasoline evaporation by distillation range, vapor pressure and gas-liquid ratio.
① Distillation range. Refers to the temperature range of gasoline fraction from the initial boiling point to the final boiling point. The distillation range of aviation gasoline is narrower than that of automobile gasoline.
② Steam pressure. Refers to the vapor pressure of 38℃ measured in standard instruments, which is an index reflecting the tendency of gasoline to generate gas resistance in the fuel system and the difficulty of engine starting. Automobile gasoline needs higher vapor pressure, while aviation gasoline needs lower vapor pressure than automobile gasoline.
③ Gas-liquid ratio. Refers to the ratio of vapor volume to liquid volume of liquid fuel at a specified temperature and atmospheric pressure in a standard instrument. The gas-liquid ratio is a function of temperature, and it is more reliable to evaluate and predict the gas resistance tendency of gasoline than to use distillation range and vapor pressure.
Blast resistance
Refers to the ability of gasoline to resist detonation combustion under various conditions of use. The antiknock performance of automobile gasoline is expressed by octane number. The higher the octane number, the better the antiknock performance. The antiknock ability of gasoline is related to its chemical composition. Branched alkanes, olefins and aromatics usually have excellent explosion resistance. The octane number of isooctane is 100, which has good antiknock performance; The octane number of n-heptane is 0, and its antiknock performance is poor. The octane number of gasoline is determined by an octane number machine. High octane gasoline can meet the needs of high compression ratio gasoline engine. The higher the compression ratio of gasoline engine, the higher the thermal efficiency, which can save fuel. Improving the octane number of gasoline mainly depends on increasing the components of high octane gasoline, but it is also achieved by adding anti-knock agents such as MTBE. The grade of gasoline is divided according to the octane number.
stability
Refers to the long-term stability of gasoline under natural conditions. Characterized by colloid, induction period and iodine value. The lower the gums, the better. The longer the induction period, the better. According to the national standard, the actual gum content per 100 ml gasoline should not be greater than 5 mg. The iodine value indicates the olefin content.
corrosivity
Corrosiveness refers to the characteristics that gasoline corrodes storage tanks, pipelines, valves, vaporizers, steel cylinders and other equipment during storage, transportation and use. It was characterized by total sulfur, mercaptan, copper sheet experiment and acid value.
safe
The index of gasoline safety performance is mainly flash point, and the flash point value strictly stipulated by national standards is ≥55℃. Too low flash point means that gasoline mixed with light components will bring security risks to the storage, transportation and use of gasoline, and will also lead to the failure of automobile engines.
6 gasoline brand
steam
Oil products are produced and sold according to brands, and brand specifications are stipulated by national gasoline product standards, which are related to different standards. At present, there are three gasoline brands in China (Ⅳ), namely 90, 93 and 97. country
(v) No.89, No.92 and No.95 respectively (No.98 in the appendix). The grade of gasoline is divided according to the octane number. For example, 97 # gasoline, that is to say, its antiknock performance is equivalent to 97% isooctane and 3% n-heptane.
Gasoline fuel. The bigger the label, the better the explosion-proof performance. Different brands of gasoline should be selected according to the engine compression ratio, which will be indicated in the user manual of each car. The compression ratio is between 8.5 and 9.5.
Generally, 90 # gasoline is used for first-class vehicles, and 93 # gasoline is used for vehicles with compression ratio greater than 9.5.
If the engine with high compression ratio uses low-grade gasoline, the cylinder temperature will rise sharply, the gasoline will not burn completely, and the machine will vibrate strongly, thus reducing the output power and parts.
Damage, fuel consumption and inability to drive. If the engine with low compression ratio uses high-grade engine oil, there will be a phenomenon of "delayed combustion", that is, the auto-ignition point will not be reached when the compression ratio is the highest, and there will also be a phenomenon of incomplete combustion, which is not harmful to the engine.
Yao benefited a lot.
In addition, the national standards also have strict regulations on the contents of various chemical components of gasoline, such as benzene and olefins. If the olefin content is too high, a colloidal substance, poly, will be produced.
Accumulate in the intake pipe and valve guide. When the engine is at normal working temperature, there is no abnormality; When the engine is turned off and cooled for a period of time, the glue will stick the valve in the valve guide. From this time on.
Machines, just
Gasoline (1 1 sheet)
There will be a phenomenon of valve jacking. The content of toxic benzene shall not exceed 65438 0%.
At present, there are three grades of gasoline on the market: 90, 93 and 97. These figures represent the octane number of gasoline, that is, the antiknock property of gasoline, which has nothing to do with the cleanliness of gasoline. The so-called "high-grade gasoline is cleaner" is purely misleading. It is more scientific and economical to refuel according to the compression ratio of the engine or the requirements of the automobile instruction manual, which can give full play to the efficiency of the engine.
In the design stage of automobile engine, the label of fuel used will be set according to the compression ratio. Compression ratio is a very important structural parameter of the engine, which means that the gas volume at the beginning of compression at the bottom dead center of the piston is higher than that at the top of the piston.
The ratio of gas volume at the end of dead point compression. In terms of power and economy, the greater the compression ratio, the better. High compression ratio, good power, high thermal efficiency, vehicle acceleration and maximum speed will also be improved accordingly. but
Due to the limitation of cylinder material performance and gasoline combustion knock, the compression ratio of gasoline engine should not be too large. Simply put, cars with high compression ratio use advanced fuel. The higher the fuel grade, the slower the engine oil combustion speed and the combustion knock.
The lower, the higher the compression ratio required by the engine; On the contrary, low-grade fuel has faster combustion speed, greater combustion knock and lower engine compression. [2]
7 ethanol gasoline
According to the standard of ethanol gasoline for automobile in China, ethanol gasoline contains ethanol 10%.