Inst. of Food Science and Nutrition, Swiss Federal Inst. of Technology (ETH), CH-8092 Zurich, Switzerland.
J Food Sci. 2010 Nov-Dec;75(9):C697-702. doi: 10.1111/j.1750-3841.2010.01822.x. Epub 2010 Oct 7.
Aroma recovery as determined by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) was compared in coffees resulting from conventional grinding processes, and from wet grinding with cold and hot water. Freshly roasted coffee as well as old, completely degassed coffee was ground in order to estimate the relationship of internal carbon dioxide pressure in freshly roasted coffee with the aroma loss during grinding. The release of volatile aroma substances during grinding was found to be related to the internal carbon dioxide pressure, and wet grinding with cold water was shown to minimize losses of aroma compounds by trapping them in water. Due to the high solubility of roasted coffee in water, the use of wet-grinding equipment is limited to processes where grinding is followed by an extraction step. Combining grinding and extraction by the use of hot water for wet grinding resulted in considerable losses of aroma compounds because of the prolonged heat impact. Therefore, a more promising two-step process involving cold wet grinding and subsequent hot extraction in a closed system was introduced. The yield of aroma compounds in the resulting coffee was substantially higher compared to conventionally ground coffee.
采用固相微萃取-气相色谱-质谱联用（SPME-GC-MS）法比较了常规研磨和冷、热水湿法研磨咖啡的香气回收情况。为了评估新鲜烘焙咖啡内部二氧化碳压力与研磨过程中香气损失的关系，我们对新鲜烘焙咖啡和完全脱气的陈咖啡进行了研磨。研究发现，研磨过程中挥发性香气物质的释放与内部二氧化碳压力有关，用冷水湿法研磨可以通过将其困在水中来最大程度地减少香气化合物的损失。由于烘焙咖啡在水中的高溶解度，湿法研磨设备的使用仅限于研磨后需要进行提取的工艺。由于长时间的热冲击，使用热水湿法研磨并结合研磨和提取，会导致大量香气化合物损失。因此，我们引入了一种更有前途的两步法，包括冷湿研磨和随后在封闭系统中进行热提取。与常规研磨咖啡相比，所得咖啡中的香气化合物收率显著提高。
