Abstract: Molecular distillation (MD) was used to purify essential oil from cumin oleoresin, obtained by supercritical carbon dioxide fluid extraction, and two important process parameters including temperature and pressure were optimized by response surface methodology for maximizing oil yield and cuminal content. Two quadratic regression model equations describing oil yield or cuminal content as a function of the two process parameters were established. Both parameters had a highly significant effect on oil yield and cuminal content. Based on numerical optimization and comprehensive considerations of oil yield and cuminal content, the optimal distillation conditions were temperature of 77 ℃and pressure of 122 Pa, resulting in an oil yield of 34.24% and a cuminal content of 30.43%.

Key words: molecular distillation, purification, cumin oleoresin, essential oil, response surface methodology