In recent decades, attraction towards the green extraction techniques has persuaded researchers to find an alternative for traditional extraction techniques. Here, the application of ultrasound assisted extraction (UAE) followed by chromatographic analysis using high performance liquid chromatography combined with diode array detection and spectral deconvolution (HPLC–DAD/SD) were investigated to quantify the main eight diterpene esters (cafestol and kahweol linoleates, oleates, palmitates and stearates) in green and roasted coffees. Factors employed were time of ultrasonication (0, 10, 20 and 30 min) and extraction solvent volume (10, 15 and 20 mL). The UAE was successfully optimized (20 min and three times extraction with diethyl ether equivalent to 15 mL) and resulted in the extraction of the considerable portion of the diterpene esters from ground coffee, representing cafestol palmitate in larger amount in green (201–739 mg/100 g) and the respective roasted ones (154–670 mg/100 g). Whereas, kahweol linoleate presented slightly higher content than kahweol palmitate either in green or roasted samples. In general, the diterpene esters content slightly decreased from green to roasted coffees, although it was not statistically significant (p > 0.05). Likewise, the profile of diterpene esters was not affected by the roasting process. The analytical method was also validated as good intra- and inter-day precisions (< 5%), good recoveries (91–101%), and high correlation coefficients (R² > 0.98) was acquired. We concluded that as a rapid and accurate approach, the UAE combined with HPLC–DAD/SD is an economic approach that can be used for monitoring of diterpene esters in either green or roasted coffee.

中文翻译：

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直接超声辅助萃取-HPLC-DAD结合光谱去卷积法测定生咖啡和烘焙咖啡中的二萜酯

近几十年来，对绿色提取技术的吸引力促使研究人员找到了传统提取技术的替代方法。在这里，我们研究了超声辅助萃取（UAE）的应用，然后使用高效液相色谱结合二极管阵列检测和光谱解卷积（HPLC-DAD / SD）进行了色谱分析，以定量确定主要的八种二萜酯（卡夫斯托尔和卡哇尔亚麻油酸酯，油，棕榈酸酯和硬脂酸酯）在绿色和烘焙咖啡中。使用的因素是超声处理的时间（0、10、20和30分钟）和萃取溶剂的体积（10、15和20 mL）。阿联酋成功地进行了优化（20分钟和三次，用相当于15 mL的二乙醚萃取），并从磨碎的咖啡中提取了相当一部分的二萜酯，代表了绿色的棕榈酸酯棕榈酸酯（201-739 mg） / 100克）和相应的烤制食品（154-670毫克/ 100克）。相比之下，在绿色或烤制样品中，卡哇尔亚油酸酯的含量略高于棕榈酸棕榈酸酯。通常，虽然从统计学上看，二萜酯类含量从生咖啡到烘焙咖啡略有下降（在绿色或烤制样品中，卡哇尔亚油酸酯的含量略高于棕榈酸棕榈酸酯。通常，虽然从统计学上看，二萜酯类含量从生咖啡到烘焙咖啡略有下降（在绿色或烤制样品中，卡哇尔亚油酸酯的含量略高于棕榈酸棕榈酸酯。通常，虽然从统计学上看，二萜酯类含量从生咖啡到烘焙咖啡略有下降（p  > 0.05）。同样，二萜酯的分布不受焙烧过程的影响。该分析方法还得到了日内和日间精度（<5％），良好的回收率（91–101％）和高相关系数（R ²  > 0.98）的验证。我们得出结论，作为一种快速，准确的方法，将阿拉伯联合酋长国与HPLC–DAD / SD结合使用是一种经济的方法，可用于监测生咖啡或烘焙咖啡中的二萜酯。