The differences in the hydrolysis rates of these starch granules were attributed to the lower protein content of the o2-maize kernels in general and the lower amylose content of the severe o2 mutant B46o2 and QPM starches than the WT counterparts when subjected to PPA hydrolysis. The starch granules in the dry-ground maize samples were also hydrolyzed faster than the starch granule isolated from whole kernels by wet milling. This difference could be attributed to the presence of mechanically damaged starch granules and endogenous amylases in the dryground maize samples. All the results suggested that the starch granules in the o2 maize and
QPM are desirable for feed and ethanol production.