Cornstarch characteristics can be changed by expressing a non-corn plant starch branching enzyme in a corn plant. In a preferred embodiment, transgenic corn plants containing the barley starch branching enzyme IIa transgene was generated. Some transgenic corn plants produced seeds containing cornstarch with lowered gelatinization temperature and retrogradation rate while others produced seeds containing cornstarch with higher retrogradation rate when compared to non-transgenic corn plants.