Cyclomaltodextrin glucanotransferases, EC 2.4.1.19, close sections of 1,4-alpha-D-glucan chains into rings by forming fresh 1,4-alpha-D-glucosidic bonds. Acting on starch and dextrins, they reversibly generate cyclomaltodextrins of six, seven or eight glucose units, known as alpha-, beta- and gamma-cyclodextrin. These ring molecules excel at encapsulating volatile compounds such as flavours and fragrances. Sourced mainly from Bacillus species, the enzymes are the industrial workhorses for manufacturing these versatile molecular carriers. The reversible nature of the reaction lets manufacturers steer product distribution by adjusting substrate concentration and removing the desired rings.