Changes in the hop-derived volatile profile upon lab scale boiling

Hop terpenes might be oxidized during kettle boiling into more water soluble compounds that could contribute to ‘hoppy’ aroma of kettle hopped lager beers. Our current research proves that the boiling process induces significant changes in the hop oil volatile profile. The discrimination between vol...

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Bibliographic Details
Published in:Food research international 2015-09, Vol.75, p.1-10
Main Authors: Praet, Tatiana, Van Opstaele, Filip, Steenackers, Bart, De Brabanter, Joseph, De Vos, Dirk, Aerts, Guido, De Cooman, Luc
Format: Article
Language:English
Subjects:
Aroma
Beer
Boiling
Derivatives
Flavours
Hop essential oil
Hoppy aroma
HS–SPME–GC–MS
Kettle boil
Kettles
Lager
Mathematical analysis
Oxygenated
Oxygenated terpenoids
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Summary:Hop terpenes might be oxidized during kettle boiling into more water soluble compounds that could contribute to ‘hoppy’ aroma of kettle hopped lager beers. Our current research proves that the boiling process induces significant changes in the hop oil volatile profile. The discrimination between volatile profiles of unboiled and boiled hop essential oil was evaluated via principal component and cluster analysis (PCA and CA). HS–SPME–GC–MS analysis revealed quantitative changes (e.g. increases in the levels of oxygenated α-humulene and β-caryophyllene derivatives) as well as qualitative changes (i.e. detection of compounds, not found in unboiled hop essential oil) in the hop oil volatile profile upon boiling. Many of these compounds were previously found in lager beer and may therefore contribute to beer flavor. Interestingly, the analytical difference between unboiled and boiled hop essential oil proved to be more pronounced as the initial hop essential oil concentration used for boiling was increased. In addition, lager beers spiked with boiled hop oil were described as ‘hoppy/spicy’ during sensory evaluations. Therefore, the newly formed products and hop oil constituents that are characterized by an increased recovery after boiling, are candidate compounds for ‘hoppy’ aroma in real brewing practice. •Analytical discrimination between unboiled and boiled hop essential oil via multivariate statistics•Increase in levels of β-caryophyllene and α-humulene derivatives upon boiling of hop oil•Compounds formed ‘de novo’ (not present in the unboiled sample) upon boiling•Non-aromatized lager beer spiked with boiled hop oil described as ‘hoppy/spicy’ during sensory trials
ISSN:0963-9969
1873-7145
DOI:10.1016/j.foodres.2015.05.022