Two processes are used for the commercial production of cyclodextrins. One is
referred to as the non-solvent process; in it, the enzyme is allowed to react with starch
in a completely aqueous environment. In the other, referred to as the solvent process,
an organic precipitant is added to direct the reaction to produce only one cyclodextrin.
Both processes use starch (corn, potato, rice, wheat, etc.) as the substrate. Corn
and potato starches are most commonly used. In both processes, the starch is hydrolyzed
to a dextrose equivalent (DE) of 3 to 8 (see Chapter 21) prior to use. 25 If liquifaction/
hydrolysis is not sufficient, retrogradation occurs. This limits the availability
of substrate, resulting in low yields of cyclodextrins, and interferes with later recovery
steps. If the starch is over-hydrolyzed, the disproportionation reaction dominates
and yields of cyclodextrins are low. If an α -amylase is used to hydrolyze the starch, it
must be inactivated by acidifi cation, raising the temperature, otherwise, the yield will
be greatly reduced.