Molecular weight of amylopectin

The molecular weight of amylopectin is appreciably higher, since according to osmotic pressure determinations it is 50,000-1,000,000. 

A further factor that causes the non-homogeneity of nitrostarch is the presence of the two components, amylose and amylopectin in starch. It has been demonstrated by nitrating each of these starch components separately that the nitration products differ from one another. Berl and Kunze [37] detected that amylopectin yields a product of a considerably higher viscosity than that resulting from the nitration of amylose. This effect may be attributable to the higher molecular weight of amylopectin. 

Determination of molecular weight of amylopectin is limited by the gel permeation chromatography columns available. Recent research indicates significant differences in amylopectin DP, with potato amylopectin being by far the largest. 

Amylopectin is a branched polymer of Ct-D-glucopyranosyl units. As in amylose, the backbone of amylopectin is linked by (X-(l,40 glycosidic bonds. The branches in amylopectin link short chains of amylose by a-(l,6 ) glycosidic bonds. Each chain in amylopectin contains about 25 (X-D-glucopyranosyl units (Figure 26.13). The molecular weight of amylopectin can be as high as 1 million. An amylopectin molecule can have as many as 300 interconnected chains. 

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