Properties of Residual Maize Starches Following Acid Hydrolysis

The properties of residual starches following initial acid hydrolysis were investigated. Starch granules of several endosperm mutants of maize, namely opaque‐2 (o2), amylose‐extender; opaque‐2 (ae o2), waxy; opaque‐2 (wx o2), dull; opaque‐2 (du o2), and sugary‐2; opaque‐2 (su2 o2) were used. Initial rate of hydrolysis for su2o2 was fastest and that for aeo2 was slowest. Following the acid hydrolysis by the enzymatic and chromatographic method, in the initial phase of hydrolysis amylose was preferentially hydrolyzed in the starches, except in the case of wx o2. In the case of wx o2 the long B chains of amylopectin were preferentially hydrolyzed. The rate of decrease in chain length of ae o2 was relatively fast and that of su2o2 was slow. Fine structures of amorphous regions in these starch granules are discussed.