Hydrophobic modification-induced self-assembly selectively enhances ice recrystallization inhibition by β-cyclodextrin.

Octenyl succinic anhydride (OSA) modification was used to regulate the ice recrystallization inhibition (IRI) activity of cyclodextrins by promoting amphiphilic self-assembly. OSA-modified α-, β-, and γ-cyclodextrins were prepared, and successful grafting was confirmed by carboxyl group analysis, FTIR, and 1H NMR. OSA modification affected IRI activity in a cyclodextrin-dependent manner: it reduced the activity of α-CD, had little effect on γ-CD, but markedly enhanced β-CD. The 5% OSA-β-CD sample showed potent activity at 3.0 mg mL-1. Fluorescence, light scattering, transmittance, and AFM analyses revealed concentration- and grafting-dependent supramolecular assembly. Mechanistic analyses indicated that the IRI activity was unlikely to result from reduced bulk-water mobility or persistent adsorption onto specific ice planes. In ice cream, 5% OSA-β-CD inhibited ice crystal growth without affecting major quality attributes.