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

Introduction: 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. Methods: 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). Conclusion: 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.