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Amylose A is a parallel double-helix of linear chains of glucose. Amylose is made up of α(1→4) bound glucose molecules. The carbon atoms on glucose are numbered, starting at the aldehyde (C=O) carbon, so, in amylose, the 1-carbon on one glucose molecule is linked to the 4-carbon on the next glucose molecule (α(1→4) bonds). [3]
A solution of triiodide (I 3 −) (formed by mixing iodine and potassium iodide) can be used to test for starch. The colorless solution turns dark blue in the presence of starch. [70] The strength of the resulting blue color depends on the amount of amylose present. Waxy starches with little or no amylose present will color red.
Damaged starch can be produced, for example, during the wheat milling process, or when drying the starch cake in a starch plant. [5] There is an inverse correlation between gelatinization temperature and glycemic index. [4] High amylose starches require more energy to break up bonds to gelatinize into starch molecules.
Natural saccharides are generally composed of simple carbohydrates called monosaccharides with general formula (CH 2 O) n where n is three or more. Examples of monosaccharides are glucose, fructose, and glyceraldehyde. [4] Polysaccharides, meanwhile, have a general formula of C x (H 2 O) y where x and y are usually large numbers between 200 and ...
Retrogradation is a reaction that takes place when the amylose and amylopectin chains in cooked, gelatinized starch realign themselves as the cooked starch cools. [1]When native starch is heated and dissolved in water, the crystalline structure of amylose and amylopectin molecules is lost and they hydrate to form a viscous solution.
The chair conformation of six-membered rings have a dihedral angle of 60° between adjacent substituents thus usually making it the most stable conformer. Since there are two possible chair conformation steric and stereoelectronic effects such as the anomeric effect, 1,3-diaxial interactions, dipoles and intramolecular hydrogen bonding must be taken into consideration when looking at relative ...
Maltose is the two-unit member of the amylose homologous series, the key structural motif of starch. When beta-amylase breaks down starch, it removes two glucose units at a time, producing maltose. An example of this reaction is found in germinating seeds, which is why it was named after malt. [4] Unlike sucrose, it is a reducing sugar. [5]
Amylopectin contains a larger number of Glucose units (2000 to 200,000) as compared to Amylose containing 200 to 1000 α-Glucose units. In contrast, amylose contains very few α(1→6) bonds, or even none at all. This causes amylose to be hydrolyzed more slowly, but also creates higher density and insolubility. [8]