Characterization of Humulus lupulus glycosides with porous graphitic carbon and sequential high performance liquid chromatography quadrupole time-of-flight mass spectrometry and high performance liquid chromatography fractionation.

Monoterpenes contribute to the characteristic aroma of several hop varieties and may occur as nonvolatile glycosides. Upon hydrolysis, the volatile terpenes are released from the glycoside precursors. Little is known, however, about the glycoside composition of hops.

Characterization of Free and Bound Monoterpene Alcohols during Riesling Fermentation.

The isomeric nature of monoterpenyl glycosides makes unambiguous identification of intact glycosides difficult. As a result, it is challenging to relate the changes in free monoterpenol concentrations to the corresponding glycosides during wine fermentation and storage. In this study, we isolated and identified linalool, nerol, and geraniol monoterpenyl glycosides fromcv.

The Occurrence of Glycosylated Aroma Precursors in Fruit and Hop Cones and Their Roles in Wine and Beer Volatile Aroma Production.

Volatile aroma compounds found in grapes and hops may be present as both free volatiles and bound glycosides. Glycosides found in the raw materials are transferred to their respective fermented beverages during production where the odorless compounds may act as a reservoir of free volatiles that may be perceived by the consumer if hydrolyzed. A review of the literature on grape and wine glycosides and the emerging literature for glycosides in hops is presented in order to demonstrate the depth of history in grape glycoside research and may help direct new research on hop glycosides.

Evaluation of Variety, Maturity, and Farm on the Concentrations of Monoterpene Diglycosides and Hop Volatile/Nonvolatile Composition in Five Cultivars.

Pentose-hexose monoterpene alcohol glycosides were isolated and semiquantitatively measured in dried cones using UHPLC-qTOF-MS/MS and HPLC fractionation followed by GC-MS. The samples evaluated included hop cones from five important dual-purpose cultivars (varieties) in the United States, from two locations (farms) per variety and from three distinct harvest time points (maturities) per location, as dictated by dry-matter (% w/w) at the time of harvest. Hop variety accounted for the biggest variation among the concentrations of pentose-hexose monoterpene alcohol glycosides as well as other volatile and nonvolatile chemical factors measured in the samples.

Direct Analysis of Glycosidic Aroma Precursors Containing Multiple Aglycone Classes in Berries.

Ultra-high-performance liquid chromatography (UHPLC) accurate mass tandem mass spectrometry is a powerful tool for identifying and profiling plant metabolites. Here, we describe an approach to characterize glycosidically bound precursors of monoterpenoids, norisoprenoids, volatile phenols, aliphatic alcohols, and sesquiterpenoids in grapes. Chromatographic separation of glycosylated compounds was evaluated using phenyl-hexyl (reverse phase), glycan/hydrophilic interaction, and porous graphitic carbon (PGC) stationary phases.