Starches

Starch is bought on functional behaviour rather than on composition: gelatinisation temperature, viscosity profile, freeze-thaw stability, clarity and texture in the finished system are what a formulator is actually specifying.

Potato starch and corn starch behave differently and are not substitutes: potato gelatinises at a lower temperature and gives higher peak viscosity and clearer gels. Choose on the application rather than on price.

Modified starches are a further layer, and the modification has to be declared and must be permitted in the destination. That permission differs between markets and is worth confirming before a formulation is locked, because a modified starch that is standard in Canada may not be approved where you are shipping.