Title: Determination of Hop Aromatisation of Beer by Headspace Solid Phase Microextraction in Combination with Gas Chromatography and Mass Spectrometry
Authors: Van Opstaele, Filip ×
Aerts, Guido
De Cooman, Luc #
Issue Date: Dec-2014
Publisher: Fachverlag Hans Carl
Series Title: BrewingScience vol:67 issue:november/december pages:149-160
Abstract: In contrast to determination of hop utilisation in terms of beer bitterness, analytical measurement of the yield
of hop aromatisation is not straightforward on account of the enormous chemical complexity of hop essential
oil and hoppy aroma derived thereof. In this paper, selective determination of hop oil-derived constituents
in the flavour profile of pilsner beer is achieved through headspace solid phase microextraction (HS-SPME)
in combination with gas chromatography-mass spectrometry (GC-MS). Highly enriched floral and spicy hop
essences were prepared by density programmed supercritical fluid extraction (SFE), followed by solid phase
extraction (SPE), and subsequently added in well-defined amounts to an experimental pilsner, exclusively
bittered with purified iso-α-acids extract. In view of reliable measurement of the yield of aromatisation of the
pilsner with the respective hop oil fractions, characteristic marker components for the floral and spicy SFE/
SPE hop essences, respectively, were selected. Reliable determination of the selected markers for floral and
spicy SFE/SPE hop essences in the aromatised beers turned out to be possible on condition that HS-SPME is
combined with GC-MS comprising selected fragment ion monitoring (SIM). Using this approach, application of
hop oil preparations can be monitored analytically, allowing improved control and specification of hop aromatisation
according to the desired beer flavour. The average yield of beer aromatisation using floral and spicy
hop essences was determined at about 95 %.
On the basis of their sesquiterpenoid GC-MS/SIM pattern, fresh commercial lager beers could be differentiated,
which may be useful for brand fingerprinting and identification. Upon forced ageing of the beers, levels of hop
oil-derived sesquiterpenoids, in particular of caryophyllene and humulene epoxides, decrease significantly. In
addition, trans-nerolidol is identified as a potential marker for measuring flavour (in)stability of pilsner beer.
ISSN: 1866-5195
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Bioengineering Technology TC, Technology Campuses Ghent and Aalst
Technologiecluster Bioengineering Technologie
× corresponding author
# (joint) last author

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