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Characterization of reduced iso‐α‐acids derived from hops ( Humulus lupulus ) by NMR
Author(s) -
Nord Lars I.,
Sørensen Steen Bech,
Duus Jens Ø.
Publication year - 2003
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1234
Subject(s) - chemistry , humulus lupulus , high performance liquid chromatography , hop (telecommunications) , nuclear magnetic resonance spectroscopy , side chain , brewing , characterization (materials science) , stereochemistry , chromatography , organic chemistry , polymer , food science , nanotechnology , fermentation , computer network , materials science , pepper , computer science
Abstract Reduced forms of iso‐α‐acids (isohumulones), used in modern beer brewing were separated and characterized by 1 H and 13 C NMR spectroscopy. Components from mixtures of rho‐iso‐α‐acids, tetrahydro‐iso‐α‐acids, and hexahydro‐iso‐α‐acids were isolated using high‐performance liquid chromatography (HPLC) and analyzed by use of one‐ and two‐dimensional NMR experiments. The data presented assign the identities of the main peaks in the HPLC traces for the reduced iso‐α‐acids. Previous tentative assignments regarding the cis and trans configurations and the structures of the acyl residues of the reduced iso‐α‐acids were confirmed and extensive NMR assignments were made. Furthermore, the previously unknown stereochemistry in the C‐4 side‐chain of the rho‐ and hexahydro‐iso‐α‐acids was assigned. Copyright © 2003 John Wiley & Sons, Ltd.