Espresso machines maintain constant the extraction process of espresso coffee (EC), however, it is difficult to grind roasted coffee in homogeneous way. This research aims to investigate grinded beans at specific particle sizes in three variously designed filter baskets and to compare the concentration of bioactive compounds while decreasing the amount of ground coffee. Analyses on caffeine, trigonelline and chlorogenic acids are carried out with HPLC-VWD, while volatiles with HS-SPME/GC-MS. Extracting with smaller particles escalates the quantity of bioactive compounds. The amount of caffeine/cup increased moving from 500-1000 µm to 200-300 µm particle size, both in Arabica and Robusta for all filter baskets. Keeping constant the volume of EC at various heights of perforated disc, the amount of bioactive compounds at 12 g were only around 9% lower than at 14 g. The outcomes will support further studies on different extraction processes, to develop more sustainable and economically affordable coffee.

中文翻译：

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通过改变颗粒大小，穿孔的圆盘高度和滤篮来优化浓缩咖啡的提取，目的是减少磨碎的咖啡量。

浓缩咖啡机保持恒定的浓缩咖啡（EC）提取过程，但是，很难以均匀的方式研磨烘焙过的咖啡。这项研究的目的是在三个设计不同的滤篮中研究特定粒径的磨豆，并比较生物活性化合物的浓度，同时减少咖啡粉的量。用HPLC-VWD分析咖啡因，松果碱和绿原酸，而用HS-SPME / GC-MS分析挥发物。用较小的颗粒萃取会增加生物活性化合物的数量。咖啡因/杯的量从500-1000 µm增加到200-300 µm，在所有过滤篮的阿拉比卡咖啡和罗布斯塔咖啡中都增加了。在穿孔盘的各种高度上保持EC的体积恒定，12克生物活性化合物的含量仅比14克低9％左右。研究结果将支持对不同提取工艺的进一步研究，以开发出更可持续，更经济实惠的咖啡。