Abstract In this study, a pressurized liquid extraction (PLE) was optimized to obtain green coffee extract rich in cafestol and kahweol diterpenes. The effects of temperature (T) and static time (St) (time of contact between the solvent and the matrix during each cycle or batch) on global yield, cafestol and kahweol concentrations and antioxidant activity were studied. The greatest green coffee extract global yield (9.78%) was obtained at 70 °C and 8 min St. PLE at 74 °C and 6 min St presented the highest concentration of cafestol (20.08 g/kg extract) in the green coffee extract, whereas, the highest kahweol concentration (25.16 g/kg extract) was obtained at 60 °C and 6 min St. The extracts showed high DPPH• antioxidant activity, particularly after PLE at 50 °C and 8 min St (EC50 1.56 μg/mL of extract). This extract also presented a high total phenolic content (35.99 mg GAE/g of extract).

中文翻译：

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富含二萜的生咖啡提取物——以乙醇为溶剂的加压液体提取工艺优化

摘要 在本研究中，对加压液体萃取 (PLE) 进行了优化，以获得富含咖啡醇和咖啡豆二萜的生咖啡提取物。研究了温度 (T) 和静态时间 (St)（在每个循环或批次期间溶剂与基质之间的接触时间）对整体产量、咖啡醇和咖啡豆醇浓度以及抗氧化活性的影响。在 70 °C 和 8 分钟 St. PLE 获得最高的生咖啡提取物全球产量 (9.78%)。在 74 °C 和 6 分钟 St 时，生咖啡提取物中咖啡醇的浓度最高（20.08 g/kg 提取物），而最高的咖啡豆醇浓度（25.16 g/kg 提取物）在 60 °C 和 6 min St 下获得。提取物显示出高 DPPH• 抗氧化活性，特别是在 PLE 50 °C 和 8 min St 后（EC50 1.56 μg/mL提取物）。