Abstract: The remaining ratio of L-ascorbyl stearate or D-isoascorbyl stearate in ethanol is measured by iodimetry to investigate their stability. The stability of L-ascorbyl stearate or D-isoascorbyl stearate in ethanol decreases when the solution is exposed to light or contained metal ion. The L-ascorbyl stearate and D-isoascorbyl stearate become more and more unstable as the solution temperature increases. Metal ion chelating agent EDTA and cane sugar can also affect their stability. In generally, L- ascorbyl stearate is more stable than D-isoascorbyl stearate under the same circumstances.

Key words: L-ascorbyl stearate, D-isoascorbyl stearate, stability