The characteristics of octenyl succinic anhydride (OSA)-modified polysaccharide could be affected by its degree of reaction. Four konjac glucomannan octenyl succinate (KGOS) samples were prepared with different substitution rates (SRs) of 1.151%, 1.514%, 1.753% and 2.247%. The critical micelle concentration (CMC) of the four KGOS materials decreased with increasing SR. Fourier transform infrared (FT-IR) spectroscopy indicated that the increase in SR had little effect on the type of acyl peak. The viscosity test indicated that with SR increase, the viscosity increased slightly at low rotational speed. The emulsion capacity (EC) and stability (ES) also increased with increasing SR, but the extent of increase was not obvious when the SR exceeded 1.753%. A similar pattern was found in confocal scanning laser microscopy (CSLM) observations and ES tests of KGOS nanoemulsions. Considering the characteristics of KGOS and the economic benefits, it is preferable to prepare KGOS with an SR of 1.514% and additions of alkalizing agent and OSA (in proportion to konjac glucomannan (KGM), w/w) of 2% and 3%, respectively, during the KGOS preparation.
Keywords: Emulsion capacity; Emulsion stability; Konjac glucomannan octenyl succiniate; Nanoemulsion; Substitution rate.
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