Cyclodextrins have been proven to form complexes with linear oil molecules and stabilize emulsions. Amphiphilic properties of cyclodextrin particles were modulated through esterification reaction between â-cyclodextrin (â-CD) and octadecenyl succinic anhydride (ODSA) under alkaline conditions. ODS-â-CD particles with degree of substitution (DS) of 0.003, 0.011, and 0.019 were obtained. The introduced hydrophobic long chain that was linked within â-CD cavity led to the change of ODS-â-CD in terms of morphological structure, surface charge density, size, and contact angle, upon which the properties and stability of the emulsions stabilized by ODS-â-CD were highly dependent. The average diameter of ODS-â-CD particles ranged from 449 to 1484 nm. With the DS increased from 0.003 to 0.019, the contact angle and absolute zeta potential value of these ODS-â-CD particles improved from 25.7° to 47.3° and 48.1 to 62.8 mV, respectively. The cage structure of â-CD crystals was transformed to channel structure, then further to amorphous structure after introduction of the octadecenyl succinylation chain. ODS-â-CD particles exhibited higher emulsifying ability compared to â-CD. The resulting Pickering emulsions formed by ODS-â-CD particles were more stable during storage. This study investigates the ability of these ODS-â-CD particles to stabilize oil-in-water emulsions with respect to their amphiphilic character and structural properties.
Emulsions Hydrogen-Ion Concentration