Improvement of O/W emulsion stability and rheological properties by highly branched cyclic dextrin and preparation of a novel emulsion gel

The objective of this study was to formulate and investigate a low-oil emulsion gel (20%, v/v) stabilized by highly branched cyclic dextrin (HBCD). The results indicated that HBCD effectively prevented the coalescence of oil droplets when the concentration reached a specific threshold (40 wt%). All samples exhibited dense network structure and elastic solid properties when stored at 4 oC. Fluorescence images showed the oil droplets tended to be irregular after refrigeration, indicating HBCD molecules aggregated under low temperature. Fourier transform infrared spectroscopy and its deconvolution results displayed a shift in the hydroxyl peak and an increase in R1046/1022. Additionally, new crystalline peaks emerged at 17° and 22° in the X-ray diffusion spectra of recrystallized HBCD samples. It suggested the hydrogen bonds and ordered structure of HBCD were increased in the emulsion gels during storage. Therefore, the formation and orderly arrangement of double helix structures of the branched chains which stabilized by hydrogen bonds promoted the recrystallization and self-assembly of HBCD, ultimately resulting in the formation of a stable gel structure. The research provided theoretical feasibility for the development of structured emulsions for functional foods.