Preparation and Characterization of a Flavor Compound Inclusion Complex in a Simple Experiment

Abstract

Flavor plays a crucial role and is the most important aspect of foods and beverages. β-Ionone is a common flavor compound with a characteristic violet-like odor. An undergraduate flavor compounds chemistry laboratory that provides preparation and characterization of the flavor compound inclusion complex between hydroxypropyl-β-cyclodextrin (HP-β-CD) as a host and β-ionone as a guest is reported. This simple laboratory experiment allows students to become familiar with the concepts of microencapsulation technology and flavor compound inclusion complexes by teaching students how to prepare and characterize the β-ionone–HP-β-CD inclusion complex. A glass flask with a long, graduated neck is used for fabrication of the inclusion complex, which facilitates observation the volume change of β-ionone with and without the addition of HP-β-CD. From the volume change, the β-ionone loading capacity can be calculated. The volume difference of β-ionone also provides an intuitive way for students to understand that β-ionone is encapsulated in HP-β-CD and that the water solubility of β-ionone is improved by encapsulation. This laboratory experiment also allows students to become familiar with the freeze-drying process, thermogravimetric analysis (TGA), and the application of TGA in characterization of the inclusion complex. Formation of the inclusion complex and analysis of the TGA results allow students to understand the characteristics of β-ionone release from the inclusion complex and the improved thermal stability of β-ionone.