Characterization of Pickering emulsions stabilized by OSA-modified sweet potato residue cellulose: Effect of degree of substitute and concentration

The aims of the present study were to modify the native sweet potato residue cellulose (NSPRC) with octenyl succinic anhydride (OSA) using DMAc/LiCl reaction system and to evaluate the formation and stability of Pickering emulsion stabilized by this modified cellulose with different degree of substitute (DS) and concentration. The results showed that the molecular structure, crystal character, contact angle and surface texture of OSA-modified sweet potato residue cellulose (OSA-SPRC) were remarkably changed compared to NSPRC. In conclusion, the hydroxyl of the NSPRC was successfully replaced by the carboxyl group of OSA. Moreover, the emulsifying ability and stability of OSA-SPRC were both higher than that of Tween 80 at the same concentration and storage time. Compared with low DS (0.0017 +/- 0.0003) OSA-SPRC, the emulsions stabilized by high DS (0.0063 +/- 0.0005) OSA-SPRC displayed better creaming index, lower particle size, uniform droplets distribution, higher apparent viscosity, and emulsion stability after storing for 15 d. Similar findings were obtained with the concentration of OSA-SPRC from 0.25% to 1.75%. The improvement in the emulsion properties was likely due to the formation of oil-OSA-SPRC particles network and the saturated adsorption of OSA-SPRC particles at the O/W interface, thereby limiting the aggregation of oil droplets. Overall, the Pickering emulsions stabilized by OSA-SPRC exhibited benign stability against coalescence. The emulsions were found to be responsive to the DS and concentration of OSA-SPRC. This research revealed the formation mechanism of the Pickering emulsion stabilized by OSA-SPRC and its main affecting factors.