Hucke J, Maier H G
Z Lebensm Unters Forsch. 1985 Jun;180(6):479-84. doi: 10.1007/BF02044298.
Quinic acid and its lactone (quinide) have been determined in coffee by capillary gas chromatography. No quinide could be detected in 14 green coffee's. After steaming of 4 green coffee's the content of quinic acid was always higher, but no quinide had been formed. During roasting, the latter can be detected when roasting loss exceed 6.5%. It increases approximately proportionally with quinic acid and amounts to 50% of the latter at 22% roasting loss. Both constituents decrease at unusual high roasting loss. In 13 commercial blends of roast coffee 2.4-6.4 g/kg quinide and 8.7-16.6 g/kg quinic acid were present. Especially high values were found in one Espresso type blend and high values in steamed and decaffeinated coffee's. In 11 commercial coffee extracts 2.0-23.2 g/kg quinide and 24.6-36.4 g/kg quinic acid were determined. At higher extraction yield, more quinic acid and quinide is formed, but at very high extraction yield the content of quinide is diminished. During holding of coffee brews at elevated temperature, quinide is slowly hydrolysed.
已通过毛细管气相色谱法测定了咖啡中的奎尼酸及其内酯（奎尼定）。在14种生咖啡豆中未检测到奎尼定。对4种生咖啡豆进行蒸煮后，奎尼酸的含量总是更高，但未形成奎尼定。在烘焙过程中，当烘焙失重超过6.5%时可检测到奎尼定。它与奎尼酸大致成比例增加，在烘焙失重22%时达到奎尼酸含量的50%。在异常高的烘焙失重情况下，这两种成分都会减少。在13种商业烘焙咖啡混合物中，奎尼定含量为2.4 - 6.4 g/kg，奎尼酸含量为8.7 - 16.6 g/kg。在一种意式浓缩咖啡类型的混合物中发现了特别高的值，在蒸煮咖啡和脱咖啡因咖啡中也有较高的值。在11种商业咖啡提取物中，测定出奎尼定含量为2.0 - 23.2 g/kg，奎尼酸含量为24.6 - 36.4 g/kg。在较高的萃取率下，会形成更多的奎尼酸和奎尼定，但在非常高的萃取率下，奎尼定的含量会减少。在将咖啡冲泡液在高温下保存期间，奎尼定会缓慢水解。
