Scale-up production of apple essences/hydroxypropyl-beta-cyclodextrin inclusion complexes: effects of the impeller type and the rotational speed on the characteristics of the inclusion complexes

Abstract Cyclodextrins (CDs), due to its unique ‘outer hydrophilic and inner hydrophobic’ structure, can be used as excellent carriers to protect active aroma compounds. The hydrodynamic conditions in the reactor substantially influence the characteristics of the cyclodextrin inclusions. Based on this, this study investigated the effects of the impeller type and the rotational speed on the characteristics of the inclusion complexes, meanwhile the corresponding scale-up process was also investigated. Results showed that the pitched blade turbine was the optimum impeller due to better axial flow performance. The average particle size, polydispersity index (PDI), loading capacity and the major aroma concentration of the inclusion complexes prepared at 5 and 120 L reactors did not have significant difference compared to the inclusion complexes prepared at 0.5 L reactor under conditions of geometry similarity and constant power per unit volume, which verified the feasibility of the scale-up rule of the encapsulation process.