Relationship of the channels of normal maize starch to the properties of its modified products

Starches from 5 inbred lines of normal maize with different relative average degrees of channelization (RADC) that could be divided into two groups (2 with RADC values of 1.49–1.52 and 3 with RADC values of 0.10–0.17) were reacted with 4 highly reactive reagents. No consistent correlations between RADC and the effects of derivatization with the 4 reagents on physical properties, either without or after surface protein removal, were found. Reaction with propylene oxide, a slowly reacting reagent whose reaction should be independent of RADC, resulted in an inverse relationship between several physical properties and RADC. The results indicate that there are inherent granular and molecular differences in the maize starches that control reactivity that are more influential than RADC (at least with the degrees of modification used), that the differences carry through chemical derivatization, and that different reagents react differently with different starches.