Effect of cellulose nanocrystals on the formation and stability of oil-in-water emulsion formed by octenyl succinic anhydride starch

Abstract

This study aimed to investigate the effect of cellulose nanocrystals (CNCs) combined with octenyl succinic anhydride modified starch (OSAS) on the stabilization of oil-in-water emulsions. Hydrogen bond and intermolecular electrostatic interaction were found in the formation of CNCs-OSAS complex as characterized by molecular dynamics simulation. A relatively stable emulsion could be formed by ultrasonic emulsification when the concentrations of CNCs-OSAS complex in the weight ratio of 2:8 and oil were 1.5 wt% and 10 wt%, respectively. Increase in Z-average diameter of emulsion prepared with the CNCs-OSAS complex (81.3 nm at 25 °C for 30 days) was considerably less than that of OSAS-stabilized emulsion (116.8 nm at 25 °C). No creaming was observed in emulsion prepared with the CNCs-OSAS complex after 30 days of storage. The apparent viscosity of emulsion stabilized by the CNCs-OSAS complex was 1.4 times as high as that of OSAS-stabilized emulsion when shear rate was 0.01 s−1. Increased viscoelasticity of emulsions in the presence of CNCs probably enhanced the interaction between droplets and delayed the creaming of emulsions. This study provided a new perspective to broaden the application of CNCs and OSAS in "green" emulsion.