Amylopectin

Amylopectin and its structure

1. AMYLOPECTIN Beenish Arshad

2. DEFINITION The non-crystallizable form of starch, consisting of branched polysaccharide chains. Amylopectin is a water-soluble polysaccharide and highly branched polymer of α-glucose units found in plants.

3.  It is one of the two components of starch, the other being amylose. Formula :  (C 6 H 10 O 5 ) n

4. Structure

5. It is highly branched glucose polymer and accounts for 80-85% starch. The glycosidic linkages are alpha 1-4 and alpha 1-6. These alpha linkages are broken down in human digestive tract by enzyme amylase. Starch in potatoes, rice corn, wheat are major food sources.

6. Insoluble in water, Why Amylopectin  is even less  soluble  due to the additional 1-6 glycosidic bonds on the branch chains, further reducing its H bonding potential and therefore reducing  solubility in water

7. Characteristics It is in branched form Its polymer units are upto 2,000,000 Its molecular weight is upto 50-500 million It is alpha 1,4 and 1,6 glycosidic linkage its inner chains are formed of 20-24 glucose subunits. Dissolved  amylopectin  starch has a lower tendency of retrogradation (gelling) during storage and cooling.

8. ‘Waxy’ starches are of almost 100% amylopectin and well suited to wafer and waffle baking. The main waxy starches available are from corn, rice (glutinous rice, sweet rice) and  sorghum . Its appearance is like white powder. It thickens at lower temperature.