Quality control of plants is essential and at the same time very challenging.In this thesis, studies involving quality issues of two plants used in the production of two popular beverages, hops (in... Show moreQuality control of plants is essential and at the same time very challenging.In this thesis, studies involving quality issues of two plants used in the production of two popular beverages, hops (in beer) and Ilex paraguariensis (yerba mate) were undertaken. Hops are used as bittering agents and to increase foam stability in beer brewing. The compounds responsible for this are cis/trans isohumulones, produced by isomerisation of the 3 _-acids present in hops. To evaluate their individual effect, they had to be obtained in gram-scale amounts. For this, 3 methods based on the use of CPC (centrifugal partition chromatography) in combination with selective precipitation methods (DCHA) of trans-isomers were developed. Trans-isohumulones were found to precipitate selectively with _-cyclodextrin. Yerba mate is a popular tea-like beverage consumed in S America made from the leaves of Ilex paraguariensis , a species unique for its high caffeine content. The detection of adulterants i.e., cogeneric authoctonous Ilex species is vital for its quality control. The metabolomic profile of 11Ilex species was determined, resulting in the clear separation of all species. Additionally, arbutin was detected (0.5-10% dw) in several of the tested species but not in I. paraguariensis, though its presence had not been formerly reported. Show less
