Corn starch molecular size

This relative molecular size difference between starch and the hydrolysis sugars gives maltodextrins and corn syrup solids their valuable functional properties for the flavor industry. 

Kerr and Severson have superimposed selective precipitation on aqueous extraction technique, by treating the soluble extract with butyl alcohol. This gives an A-fraction (designated by Kerr as crystalline amylose ) of exceptionally high iodine adsorption, but in yields amounting to only 5-6% of the starch. The products from corn and tapioca starches analyze 20.5% and 20.7% iodine adsorption respectively, as compared with a maximum value of 19.0% after four recrystallizations of the Pentasol-precipitated A-fraction from corn starch. This suggests that the A-fraction may be somewhat diversified in molecular size, and that aqueous extraction preferentially dissolves the shorter linear chains. It is not to be expected that all the molecules of a natural high polymer should be of uniform size. 

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