Basic information of Starch

Starch can be regarded as a high polymer of glucose. Starch in addition to food, the industry for dextrin, maltose, glucose, alcohol, but also for modulation printing pulp, textile sizing, paper, plastic, tablet compression drugs. May be corn, sweet potato, wild acorns and puerarin and other starch-derived material derived.

Starch amylose and amylopectin two categories. Amylose contains hundreds of glucose units, and amylopectin contains thousands of glucose units. In the natural starch in the chain accounted for 20% to 26%, it is soluble, and the rest was amylopectin. When detected with iodine solution, the amylose solution was blue, and amylopectin and iodine contact becomes reddish brown. (The reason is that amylose with long helical segments can form complexes with long chains of poly-I3 and produce blue. Amylose-iodine complex contains 19% of iodine. Amylopectin complexes with iodine to form reddish red - magenta, because the branching of amylopectin is too short for poly I 3 - to form long chains.)

Starch is the storage of nutrients in the plant, stored in seeds and tubers, all kinds of plants in the starch content is high, 62% ~ 86% of starch in rice, wheat 57% ~ 75% starch, corn Starch 65% to 72%, potato starch is more than 90%. Starch is an important part of food, chewed rice and so feel a little sweet, it is because the amylase in saliva hydrolysis of starch into a disaccharide - maltose. Food into the gastrointestinal tract, but also by pancreatic secretion of saliva amylase hydrolysis, the formation of glucose is absorbed by the small intestine wall, a human tissue nutrients. Partial hydrolysis of amylopectin produces a mixture called dextrin. Dextrin is mainly used as food additives, glue, paste, and for paper and textile manufacturing (finishing) and so on.      

Classification of starch

Starch can be divided into amylose (sugar starch) and amylopectin (starch). The former is a non-branched helical structure; the latter with 24 to 30 glucose residues in the α-1,4-glycosidic bond end to end, at the branch for the α-1,6-glucosidic bond.

Amylose iodine case of blue, amylopectin iodine was purple. This is not starch and iodine chemical reaction (reaction), but produce interaction (interaction), but the starch spiral central hole just to accommodate the iodine molecules, by van der Waals force, the two form a blue-black complex . Experiments show that the iodine molecules alone can not make the starch blue, in fact, the starch blue is the iodine molecular ion (I3).

Starch is stored in the plant nutrients, stored in seeds and tubers, all kinds of plants in the starch content is higher.

Starch development

Starch industry is an important follow-up industry of agricultural products. Over the years, starch industry has played an important role in accumulating funds, satisfying consumption, expanding employment, improving people's livelihood and serving agriculture, rural areas and farmers. In recent years, China's starch industry has continued good development trend, both the total and speed of growth, industrial structure and product structure adjustment, the application of new technologies and new equipment, or enterprise size, economic efficiency and technological level Has undergone great changes, and become one of the vitality of the national economy.

With the improvement of people's living standard and the progress of science and technology, starch product structure will be optimized. The development of starch industry is the future development of traditional starch products and high-end starch products. Glutinous starch is the future development of starch industry. trend.

The role of starch

Thicken the use of starch: Thicken is appropriate, a great impact on the quality of the dishes, therefore, is one of the basic cooking thicken. Thicken mostly for slide, fried and other cooking techniques. The common feature of these cooking methods is: quick fire. The dishes cooked in this way are essentially free of soup. But because the cooking time to add some sauce sauce and raw material itself, so that the soup looks more and more, through thickening, so that the thickening of the juice increased, and attached to the surface of raw materials, so as to achieve dish gloss, Soft and delicious flavor.

Cooking How to use starch: Starch is commonly known as "Gorgon", for the white tasteless powder, mainly from corn, sweet potato starch and other substances extracted. Can be directly edible, can also be used for wine, but also often go to the feast of cooking materials, cooking has an irreplaceable effect.

From starch to hydrogen: Hydrogen is a clean energy source, but it is difficult to produce, store and transport. US scientists have developed a hydrogen production of polysaccharides from the new technology is expected to solve these major problems in one fell swoop.

Based on this technology, the future of hydrogen-powered vehicles will be easy to store carbohydrates such as starch as fuel, carbohydrates and water under the action of a special enzyme decomposition of hydrogen, through the fuel cell to generate electricity to drive the car forward.

According to the American Association for the Advancement of Science EurekAlert website reported that the results of the United States Virginia Polytechnic Institute, Oak Ridge National Laboratory and the University of Georgia scientists made the paper published in the "Public Library of Science and Technology" magazine.

Starch, cellulose and other carbohydrates contain large amounts of hydrogen, but they are very stable, only in the role of enzyme decomposition. Using synthetic biology, scientists used a mixture of 13 enzymes to convert carbohydrates and water into carbon dioxide and hydrogen.

Experiments show that this reaction can occur at about 30 ° C and 1 atmosphere. After carbon dioxide is removed, hydrogen enters the fuel cell to produce electricity, and the byproduct water can be recycled. In the reaction, hydrogen is the main product, the efficiency of natural anaerobic decomposition of biomass than the efficiency of hydrogen production 3 times higher than the cost per pound of hydrogen may be less than 1 US dollars.

At present, the human is mainly made of natural gas hydrogen, gaseous hydrogen is not easy to transport and storage, these factors hinder the development of hydrogen-powered vehicles. Using this new technology, cars do not have to carry hydrogen tank, and only carry starch and other carbohydrates, in-situ production of hydrogen.

The researchers said the fuel tank capacity of 12 gallons of vehicles can carry about 27 kilograms of starch, equivalent to 4 kilograms of hydrogen, for cars traveling 300 miles. The energy produced per kilogram of starch is equivalent to 1.12 kilograms of gasoline.

One of the long-term goals of the US Department of Energy is to achieve a hydrogen mass storage percentage of 12, or 0.12 kilograms of hydrogen per kilogram of storage or storage material. Prior to this technology can not do this, the new technology uses polysaccharide hydrogen storage, the mass percentage can reach 13.8.

For the human body to provide energy: Starch in the human body is first decomposed into maltose by salivary amylase, then maltose into glucose. Glucose through the glycolysis process to generate pyruvate, pyruvate; or starch directly into glycolysis intermediate glucose -1-P (this part of the time and saliva is not fully mixed). And then producing pyruvic acid. Pyruvate and enzymes combine to produce acetyl-CoA. And then into the citric acid cycle. Citrate into citric acid. Citric acid cycle inside each consumption of glucose, resulting in 6 NADH, 2 FADH2 (electronic carrier). And then in the mitochondrial membrane structure of these electrons through ATPase generate large amounts of ATP, energy.