Minor-Alkaloide in coffeinhaltigen Genussmitteln

An overview is given of the contents of caffeine, theobromine, theophylline, paraxanthine, theacrine, liberine and methylliberine in cola nuts, guarana, cocoa, green and black tea, mate, and, above all, coffee. Using HPLC and a special preseparation technique quantitative values for paraxanthine in cocoa, mate and tea and for paraxanthine and theacrine in roasted coffee, soluble coffee and coffee containing drink bases were obtained. It was confirmed, that Robusta green coffees contain more theophylline, theacrine and liberine than Arabicas, and that the contents of all alkaloids are higher in unripe beans than in ripe ones. At the beginning of the storage of raw coffees, the contents decrease somewhat, during decaffeination the mass ratios are changed strongly. Almost no changes are observed on steam treating or roasting or during the manufacture of soluble coffee. In 5 commercial drink bases similar contents and ratios were found. It seems possible to estimate the percentage of coffee in such bases by determining the contents of caffeine, theobromine and paraxanthine and calculation with the aid of the values of soluble coffees.