AskDefine | Define amylose

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Noun

  1. The soluble form of starch (the insoluble form being amylopectin) that is a linear polymer of glucose.

Extensive Definition

Amylose (CAS# 9005-82-7) is a planar polymer of glucose linked mainly by α(1→4) bonds. It can be made of several thousand glucose units. It is one of the two components of starch, the other being amylopectin.
The α(1→4) bonds promote the formation of a helix structure. The structural formula of amylose is pictured at right. The number of repeated glucose subunits (n) can be many thousands (usually in the range of 300 to 3000).
Amylose starch is less readily digested than amylopectin; however, it takes up less space so is preferred for storage in plants: it makes-up about 30% of the stored starch in plants. The digestive enzyme amylase works on the ends of the starch molecule, breaking it down into sugars.
Iodine molecules fit neatly inside the helical structure of amylose, binding with the starch polymer that absorbs certain known wavelengths of light. Hence, a common test for starch is to mix it with a small amount of yellow iodine solution. In the presence of amylose, a blue-black color will be observed. The intensity of the color can be tested with a colorimeter, using a red filter to discern the concentration of starch present in the solution.
High-amylose varieties of rice have a much lower glycemic load, which could be beneficial for diabetics.

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amylose in Danish: Amylose
amylose in German: Amylose
amylose in Spanish: Amilosa
amylose in Esperanto: Amilozo
amylose in French: Amylose
amylose in Croatian: Amiloza
amylose in Indonesian: Amilosa
amylose in Italian: Amilosio
amylose in Hebrew: עמילוז
amylose in Hungarian: Amilóz
amylose in Malay (macrolanguage): Amilosa
amylose in Dutch: Amylose
amylose in Japanese: アミロース
amylose in Norwegian: Amylose
amylose in Polish: Amyloza
amylose in Russian: Амилоза
amylose in Swedish: Amylos
amylose in Turkish: Amiloz
amylose in Ukrainian: Амілоза
amylose in Chinese: 直鏈澱粉
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