Comparative study of polyphenols and caffeine in different coffee varieties affected by the degree of roasting

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

“…Caffeine (1,3,7-trimethylxanthine) is the major alkaloid present in green coffee beans which also can be found in considerable concentration in roasted coffee [36,53,54]. Because of its stimulating effect on the central nervous system, it is also the most widely known constituent of coffee [55].…”

“…Green beans of Coffea arabica contain between 0.7 and 1.6 % caffeine and of Coffea canephora between 1.5 and 4.0 % [54,56]. Two other methylxanthines are also reported in coffee brews, i.e., theobromine (3,7-dimethylxanthine) and theophylline (1,3-dimethylxanthine).…”

Determination of the Elemental Composition of Coffee Using Instrumental Methods

“…They are based on the determination of different compounds, e.g., volatile compounds, caffeine, tannins and polyphenols, lipids, individual carbohydrates like sucrose, glucose, fructose, arabinose, galactose, polysaccharides like cellulose, amino acids, vitamins B3 and PP, chlorogenic acid, trigonelline, and minerals (Bernal et al 1996;Costa Freitas and Mosca 1999;Anderson and Smith 2002;Villarreal et al 2009;Hecimovic et al 2011;Wei et al 2011). These chemical species are often measured for the purpose of discriminating coffee varieties and brands or determinting the coffee origin (Bernal et al 1996;Costa Freitas and Mosca 1999;Anderson and Smith 2002;Villarreal et al 2009;Hecimovic et al 2011). However, it should be considered that all stages involved in the production of coffee, from coffee harvesting to roasting, can change the composition of the final product (Anderson and Smith 2002;Mussatto et al 2011).…”

Exploring bitterness of traditional Chinese medicine samples by potentiometric electronic tongue and by capillary electrophoresis and liquid chromatography coupled to UV detection

“…TCM preparations are natural products derived from numerous plants and they may have bitter taste [3][4][5][6]. One obvious source of bitter taste is the presence of phenolic, polyphenolic substances and alkaloids, which are responsible for bitterness in other plant-derived products like wine [7][8][9], tea [10][11][12][13][14], coffee [15,16], olive oil [17,18], etc. Taste assessment protocols normally include human sensory panels, which are widely known to suffer from sensory fatigue effect, subjectivity and variability due to the individual physical and psychological condition of panelists [19,20].…”

“…These methods are able to predict taste parameters in the analyzed samples due to their high sensitivity towards particular substances responsible for specific taste sensation (e.g. polyphenols [7][8][9][10][11][12][13][14] and caffeine [15,16,18] are known to elicit bitter taste). Another popular approach for instrumental taste assessment is the application of "electronic tongue" systems [29].…”