The Mechanism and New Strategy on Competitive Release Effect of β‐Cyclodextrin Inclusion Complexes

Abstract

Competitive release is an important release pattern of β‐cyclodextrin (β‐CD) inclusion complexes. Releasing flavor by absorbing harmful molecules is an ideal situation. Thus, two inclusion complexes, phenethyl alcohol β‐CD inclusion (PACD) and phenol β‐CD inclusion (PNCD), were prepared and their combining capacity was studied. The binding constant of PNCD was over 9 times more than PACD. PN could accelerate the release of PACD by entering the empty β‐CD, revealing competitive release effect. However, we noticed that weak‐combining molecules also induced competitive release effect. PACD and PNCD were treated with several different competitors, demonstrating that the release behavior of β‐CD inclusion complexes could be controlled by changing competitors. However, the process lasted much longer for “weak” molecules to exchange “strong” ones. The mechanism of competitive release of β‐CD inclusion complexes was conforming to chemical equilibrium theory. The release rate could be adjusted by changing the competitors with different concentration and different combining capacity. Moreover, solid inclusion complexes could interact with gaseous competitors, revealing competitive release effect. Competitive release effect could achieve the release of flavor while absorbing harmful molecules. Also, combining capacity or solvent condition was not the determination of competitive release effect, but also an adjustment strategy for molecule release, largely expanding the application of β‐CD inclusion complexes.