Analytical methods applied for the characterization and the determination of bioactive compounds in coffee

Coffee, the one of the most popular beverages in the world, contains many bioactive compounds especially caffeine-the natural stimulant and chlorogenic acids with antioxidative properties. Other chemicals such as diterpenes may influence human serum lipids and protect from the risk of some types of cancer. All these compounds are widely determined in Coffea arabica and robusta green and roasted coffee beans, coffee brews and instant coffees to increase food quality standards. The most important analytical methods are reviewed, including these using high-performance liquid chromatography, ultraviolet spectrophotometry and voltammetry techniques, that have been applied to quantify the major bioactive compounds of coffee samples: phenols-inter alia chlorogenic acids and derivatives; methylxanthines-caffeine; trigonelline; nicotinic acid; diterpenes; and short-chain carboxylic acids. Usage of hyphenated techniques such as liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry for identification and determination of coffee constituents is also presented.