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A sweet organic compound with the general formula of Cn(H2O)m(m, n is an integer). It is divided into monosaccharide, disaccharide and polysaccharide, which are the main substances that produce heat in human body. Formerly known as "sugar" [carbohydrate; Sugar]. Such as glucose, lactose, etc. Also called "carbohydrate".

A class of organic compounds, also known as carbohydrates. It is one of the main ingredients in human food, and it is also the support and protection of plants and some animals. It can be used as an important raw material in industry.

Saccharides are aldehydes or polyhydroxy ketones containing polyhydroxy groups. It is mainly composed of three elements: C, H and O (carbon, hydrogen and oxygen). Carbohydrate is also called carbohydrate, and its molecular formula is usually represented by CN (H2O) M.

Saccharides include sucrose (brown sugar, white sugar and granulated sugar), glucose, fructose, galactose, lactose, maltose, starch, dextrin and glycogen. Among these sugars, except glucose, fructose and galactose, which can be directly absorbed by the human body for a long time, the rest of the sugars must be converted into glucose in the body to be absorbed and utilized.

It is the main heat energy provider of human body. Each gram of sugar can produce 4 kilocalories of heat energy, which is characterized by wide sources, low personality and fast heat production and heat release. Sugar is also an important substance that constitutes the body, in which glycoprotein is a component of cell membrane, mucin is a component of connective tissue, and glycolipid is indispensable to nerve tissue, and these are inseparable from carbohydrates. The total carbohydrate intake from food accounts for 60 ~ 70% of the total heat energy, and infants account for about 50 ~ 60%. If the living standard is high and the intake of protein and fat is high, the intake of carbohydrates can be reduced appropriately; Instead, demand will increase. The main sources of carbohydrates are cereals and root foods, which contain a lot of starch and a small amount of monosaccharides and disaccharides, followed by various sugars. In addition, vegetables and fruits also contain different sugars. The human body lacks carbohydrates, is often hungry, and is prone to fatigue, which will delay growth and lose weight.

When there is too much glucose in the body, the excess will be stored in the liver in the form of glycogen. When the body is short of sugar, glycogen is converted into glucose and used. Excess glucose can also be converted into adipose tissue. So eating more sugar food will make people fat.

Among all kinds of foods, the content of sugar (starch) in grains is the highest, which is the main source of sugar needed by human body.

Carbohydrate is a kind of organic matter with wide distribution and high content in biology, which exists in almost all organisms, among which the plant kingdom is the most, accounting for about 80% of its dry weight; The sugar content in human and animal organs and tissues does not exceed 2% of their dry weight; The sugar content of microorganisms accounts for about 10-30% of the dry weight of bacteria. They exist in the form of sugars or bound sugars bound to protein and lipids.

The main biological functions of carbohydrates are as energy and carbon sources, and some carbohydrates participate in the composition of cell structure.

The concept of

Saccharides are polyhydroxy (two or more) aldehydes or ketones and their derivatives or polymers. According to this, it can be divided into aldose and ketose.

The history of sugar

In ancient times, people made candy with honey. Sugar-coated almonds first appeared around Rome. The manufacturer wrapped almonds with honey and dried them in the sun to get sugar-coated almonds. This kind of candy has always been very popular with people. Verdun, located in Meuse, is the most famous producer of sugar-coated almonds. BRAQUIER company here makes sugar-coated nuts of various shapes and colors, including chocolate, roasted almonds and pistachios, all of which are carefully made by ancient methods. The production process of sugar-coated nuts is more than 10 days.

The fennel candy in Flavigny Monastery is smaller and rounder. This candy was invented in the town of Flavigny in Burgundy in 1650, and has been exported to 20 countries.

Because candy is expensive, until the18th century, only nobles could taste it. However, with the rise of colonial trade, sucrose is no longer a rarity. At this time, many candy manufacturers began to experiment with various candy formulas and mass-produced candy, thus making candy enter the homes of ordinary people. This is an important reason why we can see so many sweets today.

Chemical classification of sugar

Sugar can also be divided into triose, special sugar, pentose and hexose according to the number of carbon layers. The simplest sugar is triose (glyceraldehyde and dihydroxyacetone). Because most carbohydrates can be represented by the general formula Cn (H2O)n, people used to think that sugar is a compound of carbon and water, which is called carbohydrate. Now this name is very appropriate, but after a long time, many people still call it carbohydrate.

Types of sugar

According to the number of structural units of sugar, it can be divided into: (1) monosaccharide: sugar that cannot be hydrolyzed into smaller molecules. (2) Oligosaccharide: 2-6 monosaccharide molecules are dehydrated and condensed, and disaccharide is the most common and significant. (3) Polysaccharide: homogeneous polysaccharide: starch, glycogen, cellulose, hemicellulose, chitin (chitin) heterogeneous polysaccharide: glycosaminoglycan (hyaluronic acid, chondroitin sulfate, dermatan sulfate, etc. (4) bound sugars (complex carbohydrates, glycoconjugates): glycolipids, glycoproteins (proteoglycans) and sugars-.

Biological function of sugar

(1) provides energy. Plant starch and animal glycogen are both forms of energy storage. (2) The carbon skeleton of substance metabolism provides the carbon skeleton for the synthesis of protein, nucleic acid and lipid. (3) the skeleton of the cell. Cellulose, hemicellulose and lignin are the main components of plant cell wall, and peptidoglycan is the main component of cell wall. (4) Recognition between cells and biomolecules. Oligosaccharide chains of glycoprotein on cell membrane surface participate in cell-to-cell recognition. Some cells contain sugar molecules or oligosaccharide chains on the surface of cell membrane, which form the antenna of cells and participate in cell communication. ABO blood group determinant on the surface of red blood cells contains fucose.

How is sugar absorbed by human body?

Sugar, also known as carbohydrate, includes sucrose (brown sugar, white sugar, granulated sugar and yellow sugar), glucose, fructose, galactose, lactose, maltose, starch, dextrin and glycogen marshmallow. Among these sugars, except glucose, fructose and galactose, which can be directly absorbed by the human body for a long time, the rest of the sugars must be converted into glucose in the body to be absorbed and utilized.

The effect of sugar on human body

The main function of sugar is to provide heat energy. Each gram of glucose is oxidized in the human body to generate 4 kilocalories of energy, and about 70% of the energy needed by the human body is provided by sugar. In addition, sugar is an important substance that constitutes tissues and protects liver function.

Harm of sugar to human body

Sucrose is the highest calorie carbohydrate. Excessive intake can cause obesity, arteriosclerosis, hypertension, diabetes and dental caries.

A synthesis method of sucralose is characterized in that sucrose is used as raw material, N, N- dimethylformamide solution is added, and under the action of sulfate solid acid catalyst adsorbed on polymer carrier or sulfate solid acid catalyst, ester exchange reaction occurs with ethyl acetate to generate sucrose -6- acetate, and then trichlorosucrose is generated through chlorination and alcoholysis reaction. The invention has the advantages of simple process, high product purity, low production cost and the like, and is very suitable for industrial production.

Eating too much sugar affects children's growth.

Eating too much sugar will affect the consumption of body fat and cause fat accumulation; Eating too much sugar can also affect calcium metabolism. Some scholars believe that if the sugar consumption reaches 16- 18% of the total food consumption, the calcium metabolism in the body will be disordered and the calcification in the body will be hindered. A survey in Japan shows that the fracture rate of children has increased, and they think that too much sugar is an important cause of fracture.

Eating too much sugar will make people feel full and have poor appetite, which will affect food intake and lead to various nutrient deficiencies. Children's long-term high-sugar diet directly affects the growth and development of children's bones, leading to rickets. If children eat too much sugar and don't pay attention to oral hygiene, it provides good conditions for the growth and reproduction of oral bacteria, which is easy to cause dental caries and oral ulcers.

In order to avoid diseases such as dental caries, myopia, rickets and digestive tract, the World Health Organization appeals to parents not to let their children eat too many sweets.

Sugar is one of the important substances for human survival.

Sugar is one of the three nutrients in human body and the main source of heat energy. The heat energy provided by sugar accounts for about 60 ~ 70% of the total heat energy needed by human body. Except cellulose, all sugars are sources of heat energy.

Sugar is the most abundant organic compound in nature. Sugar mainly exists in cereals, cereals, potatoes, beans, rice flour products, vegetables and fruits in various forms of starch, sugar and cellulose. It accounts for about 80% of its dry matter in plants, and the sugar in animal food is very small, accounting for about 2% of its dry matter.

Eat sugar at 2 pm to reduce car accidents

Many researchers have confirmed that grasping the best time to eat sugar is beneficial to the human body as long as it is taken in moderation. For example, if you take a bath, you need to sweat a lot, consume physical strength, and need to replenish water and calories. Eating sugar can prevent collapse; You need to consume heat when you exercise. Sugar can provide heat energy faster than other foods. When you are tired and hungry, sugar can be quickly absorbed to improve blood sugar; When you feel dizzy and sick, eating some sugar can raise your blood sugar, stabilize your mood and help you return to normal. Eating some sugary foods after meals can make people refreshed and energetic when studying and working. According to reports, American scientists' experiments on more than a thousand primary and secondary school students show that only 2% of them doze off after meals 1-2 classes, while the control group (not eating chocolate) is as high as 1 1%. In addition, hundreds of drivers were tested, and it was found that when they were required to eat chocolate, dessert or sweet drinks at 2 pm every day, the accident rate was much lower.

Eating too much sweets is easy to get various diseases.

Some experts believe that sugar is more harmful to human body than cigarettes and alcoholic beverages. The World Health Organization has investigated the causes of death in 23 countries, and concluded that sugar addiction is more harmful than smoking, and long-term consumption of foods with high sugar content will shorten people's life span by 20 years. Therefore, in 1995, the World Health Organization put forward a new slogan of "global sugar ban". A survey by the World Health Organization found that eating too much sugar can lead to heart disease, hypertension, arteriosclerosis, cerebral hemorrhage and diabetes.

Long-term high-sugar diet will make the internal environment of human body unbalanced, and then cause various hazards to human health. Because sugar is an acidic substance, eating too much sugar will change the pH of human blood, present an acidic constitution, weaken the resistance of human white blood cells to external viruses, and make people susceptible to various diseases.

People who love sweets for a long time are likely to cause a variety of eye diseases. Experts also suggested that senile cataracts are also related to excessive sweets. They investigated 50 cataract patients and found that 34% of them have the habit of eating sweets, which they think is related to the disorder of glucose metabolism.

There is no basis for obesity caused by eating sugar.

Many domestic food nutrition and medical experts believe that simple obesity is caused by the imbalance of total calorie intake and consumption, and obesity cannot be attributed to sugar. According to the research results of the working group of the US Food and Drug Administration, it is unfounded to think that sugar causes obesity. The reason is that each tablespoon of sugar contains 16 calories, while each tablespoon of butter or other high-fat foods contains 100 calories, so sugar is not the cause of obesity.

The research of several Swedish medical scientists further confirmed that eating sugar will not lead to the formation of fat layer in human body. This research result is called "Little Revolution". According to the observation of medical scientists, fat is always more than sugar in fat food, so people who lose weight must first reduce the intake of fatty foods. Astrou of Sweden, a famous European nutritionist, thinks that if you don't eat too much fatty food, you can safely increase the amount of sugar without worrying about obesity.

Moderate consumption will not affect health.

In recent years, due to more and more articles reporting the harm of sugar to human health, some one-sided publicity has made people worry about eating sugar, and they think that "eating sugar is terrible". The conclusion of the sugar research task force of the US Food and Drug Administration is that sugar can cause other diseases besides dental caries, which is unfounded. As a part of a reasonable diet, eating sugar, like eating other things, will not be harmful to the body as long as it is eaten in moderation.

Classification of sweetness of sugar

People like sweetness, and sweetness is associated with sugar. Sucrose, glucose and maltose are common sugars. They are not only sweet in taste, but also substances that supply human energy. Honey contains fructose and glucose. Fructose is the sweetest sugar. According to the experimental measurement, the sweetness ratio of fructose, sucrose and glucose is 9: 5: 4.

No sugar

Does all sugar taste sweet? No. For example, there is 4% lactose in milk, which is a sweet sugar. On the other hand, are all sweet things sugar? You can't say that either. For example, although ethylene glycol and glycerol are sweet, they are not sugar.

The exact definition of sugar

So, how should sugar be defined? Generally speaking, polyhydroxyaldehydes or polyhydroxyketones or organic compounds that can become one of the above two after hydrolysis are chemically called sugars, and this definition is not necessarily related to sweetness.

As a sweet substance, people often eat white sugar, brown sugar and rock sugar. The method of making sugar is not complicated. Juice sugarcane or beet, filtering to remove impurities, adding appropriate amount of lime water to neutralize acid contained in the filtrate, filtering to remove precipitate, introducing carbon dioxide into the filtrate to precipitate lime water into calcium carbonate, and repeatedly filtering to obtain the filtrate, namely sucrose aqueous solution. When the sucrose aqueous solution is evaporated, concentrated and cooled under reduced pressure in vacuum, reddish-brown slightly viscous crystals are separated out, which is brown sugar. To make white sugar, it is necessary to dissolve brown sugar in water, add appropriate amount of bone carbon or activated carbon, adsorb colored substances in brown sugar water, filter, heat, concentrate and cool the filtrate, and a white crystal-white sugar appears. White sugar is much purer than brown sugar, but it still contains some water. Then the white sugar is heated to a proper temperature to remove water, and colorless and transparent block crystal rock sugar is obtained. It can be seen that rock sugar has the highest purity and the sweetest taste.

Speaking of sweet substances, people naturally think of saccharin, which is not the essence of sugar. It is not extracted from sugar, but made from black and smelly coal tar. Saccharin has no nutritional value. A small amount of saccharin is harmless to human body, but excessive consumption of saccharin is harmful to human body. So saccharin is edible, but don't use too much.

PS: potatoes, yams, sweet potatoes, taro, etc. Rich in starch, sucrose, grains (such as rice, wheat, corn, barley, oats, sorghum, etc. ), fruits (such as sugar cane, melon, watermelon, banana, grape, etc. ), nuts, vegetables (such as carrots, sweet potatoes and so on. ).