What are the foods that turn blue when iodine is encountered

Starch can adsorb iodine, so that the wavelength of visible light absorbed by iodine shifts to a short wavelength, and the brown iodine solution turns blue. Similarly, amylopectin and dextrin can also adsorb iodine, but to different degrees, so they appear in different colors. The strong basis for this explanation is that the starch liquid of iodine disappears blue when heated.

This is thought to be due to the increase in molecular kinetic energy after heating, which causes desorption.

In recent years, advanced analytical techniques (such as X-ray, infrared spectroscopy, etc.) have been used to study the blue matter formed by iodine and starch, and it has been proved that the color development of iodine and starch is mainly due to the formation of inclusion complexes in addition to adsorption.

What are clusions? Amylose is a long, spirochete formed by the condensation of -glucose molecules, and each glucose unit still has a hydroxyl group exposed outside the helix. The iodine molecule interacts with these hydroxyl groups to embed the iodine molecule into the axial part of the myrospirocheta.

This effect of iodine and starch is called clallification, and the product is called clathing.

In the inclusion complex formed by starch and iodine, each iodine molecule is matched with 6 glucose units, and the starch chain is wound into a helix with a diameter, and the iodine molecule is at the axis of the helix.

The color of the cladding complex produced by starch and iodine is related to the degree of polymerization or relative molecular weight of starch. In a certain range of polymerization or relative molecular mass, with the increase of polymerization degree or relative molecular weight, the color change ratio of the inclusion complex changes from colorless, orange, light red, purple to blue. For example, when the degree of polymerization of amylose is 200 980 or the relative molecular mass range is 32000 160000, the color of the inclusion complex is blue.

Amylopectin, which has a lot of branches, has an average degree of amylopectin on the branched chain with an average degree of polymerization of 20 28, and the inclusion complex thus formed is purple. The degree of polymerization of dextrin is lower, showing brownish-red, red, light red, etc. The following table shows the degree of polymerization of starch and the color of iodine clad complex.

The inclusion complex formed by starch and iodine is most stable at pH=4, so its color reaction is most obvious in slightly acidic solutions.

According to the nature of starch, starch turns blue when exposed to iodine

My guess is: starch turns blue when exposed to iodine;

Experimental method: take a piece of potato slice and add a few drops of iodine wine dropwise;

Experimental Phenomenon: Potato chips turn blue;

Conclusion and explanation: The main component of potatoes is starch, and starch turns blue when exposed to iodine It can verify that other starch-rich substances such as steamed bread and bread can be verified

Therefore, the answer is: starch turns blue when exposed to iodine; Take a slice of potato and add a few drops of iodine wine dropwise; The potato chips turn blue; The main component of potatoes is starch, which turns blue when exposed to iodine; It turns blue when it encounters iodine

Which of the following substances appears blue when exposed to iodine? c

a.Blood. b.Butter.

c.Potato.

d.Which of the following is not necessary for photosynthesis? b

a.Light. b.Oxygen.

c.Chlorophyll.

d.Carbon dioxide.

In the process of photosynthesis, light energy is converted into (c).

a.Sound energy. b.Thermal energy.

c.Chemical.

d.Kinetic energy. The main product of photosynthesis is (b).

a.Carbon dioxide.

b.Starch. c.Alcohol.

d.What can absorb carbon dioxide on aquatic plants? (a )

a.Blade. b.Flower cRoot.

d.Seed. What happens when a small amount of clarified lime water is injected into a bottle of exhaled gas? (b )a.There is no visible change in the phenomenon.

b.The lime water becomes turbid.

c.Lime water turns yellow.

d.The lime water turns red.

Exhaled air contains less (a) than fresh air

a.Oxygen. b.Nitrogen.

c.Carbon dioxide.

d.Water vapour. In the process of respiration, the following phenomena do not occur (d).

a.Consumption of oxygen.

b.Heat energy is released.

c.Consume food.

d.Thermal energy is converted into chemical energy.

Foods with a lot of starch, such as pasta, potatoes, taro, etc.

Starchy foods, such as steamed buns.

Amylose is blue when exposed to iodine, which is not because starch and iodine have a chemical reaction (reaction), but an interaction, but the starch helix ** hole can accommodate iodine molecules, and through van der Waals forces, the two form a blue-black miscombination. Experiments have shown that iodine molecules alone cannot make starch blue, and it is actually iodine molecular ions (i3) that make starch blue

It is often said that iodine turns blue when it meets starch, which means that the amylose solution turns blue when it meets the iodine solution. In iodine solution, it is commonly used to have elemental molecules of iodine in iodine solution. Iodized salt will not turn blue when sprinkled on the beans.

When iodine encounters a starch solution, it turns blue and undergoes a chemical reaction to produce a bluish substance.

When the dot leaves encounter starch, they will turn blue and a chemical reaction will occur.

When a certain food is dripped with iodine, it turns blue, indicating that it contains: starch

Starch is a polymer compound. The essence of the reaction between starch and iodine wine is to produce a inclusion complex (the iodine molecule is encapsulated in the helical structure of the starch molecule), and this new substance changes the color due to the change of light absorption properties. Natural starch composition can be divided into two categories:

Amylose and amylopectin.

The amylose index deficiency accounts for about 10%-30%, the molecular weight is small, about 50,000, and it can be soluble in hot water (70-80) to form a colloidal solution. Amylose and iodine appear blue.

Because the characteristic of starch is that iodine turns blue, iodine wine contains iodine element, so drop 1 2 drops of iodine wine on the surface of a certain food, if it turns blue, it proves that it contains starch

Drop 1 2 drops of iodine wine on the surface of a certain food, and its surface will immediately appear blue, according to the characteristics of starch encountering iodine turning blue, indicating that potatoes contain starch Therefore, choose b Comments: This question examines the characteristics of starch, and you can solve the problem correctly if you are familiar with starch when it encounters iodine turning blue

Drizzling iodine wine on the mantou crumbs, the mantou crumbs turn blue, according to the characteristics of starch encountering iodine turning blue, indicating that the mantou crumbs contain starch

Because we know that starch turns blue-purple when it meets iodine, because starch has amylose, and the reaction with iodine is blue, and amylopectin and iodine are purple and clear, there are both amylopectin and amylose in starch, and iodine is blue-purple, and starch is a polysaccharide in sugars.