Impact of Grinding Procedure on the Yield and Quality of the Extract from Clove Buds Using Supercritical Fluid Extraction

The effects of the grinding procedure on the supercritical fluid extraction (SFE) yields of eugenol, β-caryophyllene, α-humulene, and eugenyl acetate from clove are discussed in detail in this paper. For this purpose, five grinding procedures were employed: 1) continuous 1-min grinding, 2) continuous 2-min grinding, 3) two 1-min grinding periods with 6-min stop in between 4) continuous 4-min grinding, and 5) four 1-min grinding periods with 6-min stops in between. After that, the extractor was filled with 12 g of milled clove obtained using one of the grinding procedures while the other SFE parameters were kept constant (pressure of 150 bar, temperature of 40 °C, supercritical CO2 flow rate of 1.03×10−4 kg/s, static time of 20 min, and dynamic extraction time of 15 min). Then, the composition of the extract was evaluated by gas chromatography (GC). It was found that the grinding procedure has considerable effects on the recoveries of eugenol, β-caryophyllene, α-humulene, and eugenyl acetate from clove, and employing four 1-min grinding periods with 6-min stops in between as the grinding procedure gave the highest content of the aforementioned components in the extract.