Extraction of coffee diterpenes and coffee oil using supercritical carbon dioxide

Commercial green and roasted coffee beans were used to maximize oil extraction and conditions were studied to obtain the highest and lowest diterpene levels on green and roasted coffee oil, respectively. Thus, operational temperatures (60–90 °C) and pressure (235–380 bar) were optimized for coffee oil extraction. Oil content levels and diterpene oil concentration were compared to the results obtained with the extraction with Soxhlet apparatus, using hexane as solvent. In general, an inverse correlation was observed between the amount of extracted oil and diterpene concentration levels. As a result, different oil contents with different diterpene concentrations could be obtained. The HPLC analysis of cafestol and kahweol in the oil extracted from green coffee beans at 70 °C/253 bar resulted in the highest concentration (453.3 mg 100 g⁻¹), which was 48% lower than in the oil extracted with hexane while in the oil extracted from roasted coffee beans at 70 °C/371 bar, resulted in 71.2% reduction of diterpenes.