Green extraction and separation of Dendranthema indicum essential oil by supercritical carbon dioxide extraction combined with molecular distillation

The optimal extraction parameters of Dendranthema indicum extract using supercritical carbon dioxide extraction were organized by response surface methodology (RSM) with Box -Behnken design (BBD). The peak extraction yield (9.37%) was obtained in the condition of 750 W of microwave power, 40 degrees C of extraction temperature, 26 MPa of extraction pressure, and 105 min of extraction time. Subsequently, molecular distillation was applied to separate essential oil from D. indicum extract. The separation yield of D. indicum essential oil obtained at 80 (DIEO80) and 90 degrees C (DIEO90) were 0.21 g/100 g and 0.44 g/100 g, respectively, which was lower than those of 100, 110 and 120 degrees C, while they presented transparent with no precipitate. DIEO90 possessed the strongest antioxidant activities (16.08 mu mol TE/g for 1,1-diphenyl-2-picrylhydrazyl scavenging activity, 46.05 mu mol TE/g for ferric reducing antioxidant power, respectively). Furthermore, alkenes, alcohols and esters were identified the main volatile flavor components for D. indicum extract and essential oils. The proportions of major contributing components such as 1,8-cineol (6.45%-15.04%), isopinocarveol (6.02%-11.78%), (E)-alpha-bergamotene (3.02%- 5.62%), (E)-beta-famesene (2.80%-12.92%), germacrene D (2.83%-8.23%), 6-ethenyl-2,2,6-trimethyloxan-3-ol (5.86%-6.88%), (6-Ethenyl-2,2,6-trimethyl-oxa-n-3-yl) acetate (9.11%-10.51%) and beta-elemene (4.16%- 6.44%). Though molecular distillation, compounds with low boiling points were enriched in DIEO80 and DIEO90, and compounds with high boiling points were in other oils. Overall, the sequential green process based on supercritical carbon dioxide extraction with molecular distillation is an efficient method for extraction and separation of essential oil.

Automated summary

This study utilized supercritical carbon dioxide extraction and molecular distillation techniques for the extraction and separation of essential oils from Dendranthema indicum extract. The optimal extraction parameters were determined by response surface methodology, and the main volatile flavor components in D. indicum extract and essential oils were identified. During the molecular distillation process, compounds with low boiling points were enriched in oils obtained at certain temperatures, while compounds with high boiling points were enriched in oils obtained at other temperatures.