Search results
Results from the WOW.Com Content Network
Amylopectin / ˌ æ m ɪ l oʊ ˈ p ɛ k t ɪ n / is a water-insoluble [1] [2] polysaccharide and highly branched polymer of α-glucose units found in plants. It is one of the two components of starch, the other being amylose. Relation of amylopectin to starch granule. Plants store starch within specialized organelles called amyloplasts. To ...
It is made up of a mixture of amylose (15–20%) and amylopectin (80–85%). Amylose consists of a linear chain of several hundred glucose molecules, and Amylopectin is a branched molecule made of several thousand glucose units (every chain of 24–30 glucose units is one unit of Amylopectin). Starches are insoluble in water.
Depending on the plant, starch generally contains 20 to 25% amylose and 75 to 80% amylopectin by weight. [4] Glycogen, the energy reserve of animals, is a more highly branched version of amylopectin. In industry, starch is often converted into sugars, for example by malting.
The amylopectin consists of chain of α-D-(1-4) and α-D-(1-6)-glucosidic linkages that form a branched molecule. Amylose is primarily linear with α-D-(1-4)-linked glucose residues. The locus Wx codes for a specific starch granule-bound enzyme, NDP-glucose-starch glucosyltransferase .
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] The structural formula of amylose is pictured at right. The number of ...
Starch gelatinization is a process of breaking down of intermolecular bonds of starch molecules in the presence of water and heat, allowing the hydrogen bonding sites (the hydroxyl hydrogen and oxygen) to engage more water. This irreversibly dissolves the starch granule in water. Water acts as a plasticizer.
Raw starch granules resist digestion, e.g., raw bananas, raw potatoes. This does not depend on the amylose or amylopectin content, but rather the structure of the granule protecting the starch. When starch granules are cooked, water is absorbed into the granule causing swelling and increased size.
Two common examples are cellulose, a main component of the cell wall in plants, and starch, a name derived from the Anglo-Saxon stercan, meaning to stiffen. [ 2 ] To name a polysaccharide composed of a single type of monosaccharide, that is a homopolysaccharide, the ending “-ose” of the monosaccharide is replaced with “-an”. [ 3 ]