Polymer amylopectin

Amylopectin accounts for the remaining 80% of starch and is more complex in structure than amylo.se. Unlike cellulose and amvlose, which are linear polymers, amylopectin contains 1- 6-cr-glycoside branches approximately every 25 glucose units. 

Starch molecules are polymers of anhydroglucose and occur in both linear and branched form. The degree of polymerization and, accordingly, the molecular weight of the naturally occurring starch molecules vary radically. Furthermore, they vary in the ratio of branched-chain polymers (amylopectin) to linear-chain polymers (amylose), both within a given type of starch and from one type to another. These factors, in addition to any type of chemical modification used, affect the viscosity, texture, and stability of the starch sols significantly. 

Starch is the other carbohydrate-based feedstock. Approximately 10 Mt is produced annually from corn (maize), wheat and potato, out of a total agricultural production of 1.6 Gt a-1 carbohydrate equivalents. A minor fraction of starch is amylose, a linear a 1 ->4 polymer of glucose (Fig. 8.2b). The native structure of amylose is helical loose random coils are formed upon dissolution in water. The branched glucose polymer amylopectin is the major (approximately 75%) component of starch. 

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