3.3.3.1 Starch

3.3.3.1 Starch

Starch is a polymer of glucose. It yields only glucose on hydrolysis and hence is a homopolysaccharide and is called a glucosan or glucan. The two chief constituents of starch are amylose (15-20%), which has a non branching helical structure, with glucose units linked by α(1-4)-glucosidic bond in the chains and amylopectin (80-85%), which consists of branched chains composed of 24-30 glucose residues united by α (1-4) glucosidic linkages in the chains and by α (1-6) glucosidic linkages at the branch points.                                                                   

                                                          

 

Structure of amylose

                                                  

Structure of Amylopectin

 

Structure of Amylopectin

                                                                         

Starch is the most important food source of carbohydrate and is found in cereals, potatoes, legumes, and other vegetables. Rich sources of starch are grains such as wheat, rice, corn, oats, millets and barley, legumes such as peas, beans and lentils and tubers such as potatoes, yam and cassava. 

Last modified: Thursday, 10 November 2011, 6:25 AM