What is the smell of a sun-dried quilt?


In life, we will find that the quilt that has been exposed to the sun will have a very good smell, this smell is often called "the taste of the sun" or "the taste of the sun", of course, the sun will not have a taste, this smell should still be emitted by the quilt, some experts explain that in fact, this smell is actually emitted by the mites hidden in the quilt after being burned by the sun, so it is actually the smell of mites, so is this really the case?

What are mites? It is a small arthropod, belonging to the arthropod phylum Arachnidae Broad-bellied suborder, and spiders belong to the same arachnids, but its size is much smaller, the body length is generally about 0.5 mm, some as small as 0.1 mm, most species are less than 1 mm, adults have 4 pairs of feet, a pair of tentacles, no wings and antennae, it is known that there are more than 50,000 kinds of mites in the world, some of which can burrow into human skin to become parasites, and some of them live in human clothing, bedding, pillowcases, including leather mites, chigger mites, scabies mites, worm mites, powder mites, dust mites and pampa mites, etc., many species can bite people to suck blood, suck oil, invade the skin, and seriously endanger human health.

However, mites are very afraid of strong light, because mites are small, the body surface protection tissue is thin, strong light can evaporate the water in the mite body, change the molecular structure of the mite body surface, etc., so strong light can kill some mites, so people can also destroy some mites in the next life.

So is the so-called "smell of sunlight" after drying the bedding the smell released when mites are killed? If you think so, I have to say that I think too much, and experiments have found that the number of mites that the sun's strong light can kill is very limited, and unless it is very strong sunlight exposure, it will kill mites.

Moreover, the mites killed in this way are not what anyone thinks is that the sun scorches the mites, the energy of the sun exposure is only a few tens of degrees Celsius on the quilt, it is impossible to scorch the mites, and even if it is scorched, it is impossible to have a good smell, the composition of mites this arthropod is just protein, fat and carbohydrates, the taste of burning on the fire can refer to the smell of roasted meat, burning feathers or burning a few hairs, the burnt smell is not good, and the so-called " The taste of the sun "varies greatly.

And in the current living and sanitary conditions, people's commonly used bedding or clothing are very clean, the number of mites on them is very small, it is impossible to cause the mites to emit a great taste due to sun exposure.

Therefore, it can be concluded that the "sun smell" after drying the quilt is not actually the smell of mites being burned, so what is its taste? The experiment found that it should be the oxidative photochemical action of the dry cloth surface material and the odor produced by the photochemical action of some human fat under the photochemical action of sunlight.

In February 2020, Matthew M. M. of the University of Copenhagen, Denmark. The team led by Professor S. Johnson analyzed the gas composition emitted on the surface of the outdoor sun-dried cotton towel by using thermal desorption gas chromatography/mass spectrometry (TD-GC/MS), and compared it with the gas composition emitted by the outdoor dry or indoor dried towel, and found that the towel dried by outdoor sunlight can emit a large number of C5-C9 carbon oxide compounds, such as aldehydes, ketones, carboxylic acids, etc., including valeraldehyde, hexanal, heptaldehyde, octanal and nonanal, etc., especially 2-methylpropionic acid. And these substances are also tasteful, and some taste similar to certain aromatic hydrocarbons, such as 2-methylpropionic acid, smell better. However, no such substances were found in towels under outdoor drying and indoor drying conditions, which shows that the production of this smell is really the credit of sunlight.

It has also been found that hydrogen bonds can be formed between cotton fibers, which can maintain a pleasant smell for a long time after sunlight. The oil secreted by the human body and some cosmetics creams will also be left on bedding or clothing, and some of the compounds can melt and volatilize under sunlight, producing a relatively good smell.

Therefore, the researchers believe that these substances are the cause of the pleasant "smell of the sun" released by bedding or clothing after being irradiated by the sun, rather than the smell of mites after being burned by the sun