Preparation of pickering emulsions stabilised by octenyl succinic anhydride modified α-cyclodextrins for improving storage stability and curcumin bioavailability

In this work, octenyl succinic anhydride (OSA) modified alpha-cyclodextrins (alpha-CDs) with different degrees of substitution (DS) were prepared as a novel emulsifier particles to improve emulsion stability and bioavailability of curcumin. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance verified the successful esterification of OSA with alpha-CDs. The DS of alpha-CD increased significantly (from 0.000 to 0.025) with increasing OSA addition (from 0% to 9%). The morphology of OSA-alpha-CDs was changed and the thermal stability was decreased. Zeta potential and particle size were significantly changed. At DS = 0.017, the particle size was minimum with uniformity and stability. Compared to alpha-CD, Pickering emulsions prepared from OSA-alpha-CDs had smaller and uniformly distributed emulsion particle sizes. It possessed good storage stability after 30 days of storage. For Pickering emulsions loaded with curcumin, the OSA-alpha-CD stabilised emulsion (DS = 0.017) showed the greatest encapsulation efficiency of 81.22% for curcumin. In addition, emulsions with smaller particle size had higher free fatty acid release and increased bioavailability by 10.3%. These findings provided some theoretical basis for the development and utilization of novel emulsifiers and the application aspects of using emulsions as carriers for delivering functional factors.