Diterpenoide im Kaffee

Summary A method for the determination of free and total atractyligenin in green and roast coffee is described. Free atractyligenin is extracted from aqueous extracts with ethyl acetate, then separated by thin layer chromatography and determined by reflectance photometry. Total atractyligenin is determined in the same way after enzymatic hydrolysis. In 5 samples ofArabica green coffee 0–0.01 g/kg free and 0.4–0.7 g/kg total atractyligenin have been found. In 6 samples ofRobusta green coffee no free and only in I sample traces of total atractyligenin could be detected. Green coffee of the speciesExcelsa (5 samples, free: 0.01–0.02; total: 1.2–1.6 g/kg) andLiberica (1 sample, free: 0.02; total: 1.4 g/kg) contained greater amounts. The contents in the speciesArabusta lie between those inArabica andRobusta. Several samples of roasted coffee and 7 commercial blends contained an average of about twice the amount of total and 5–10 times the amount of free atracytyligenin as compared to the amount present in green coffee. The content of free atractyligenin increases with the degree of roast, the content of total atractyligenin decreases.