Determination of Volatile Markers from Magnum Hops in Beer by In-Tube Extraction—Gas Chromatography—Mass Spectrometry

ABSTRACT

A chromatographic method was developed for the identification of volatile markers from Magnum hops in two types of beer. The study was initially performed with Magnum hop pellets and hop essential oil and subsequently with traditional and flavored beer during the primary fermentation. The volatile compounds were isolated employing the in-tube extraction (ITEX) technique followed by identification and quantification through gas-chromatography—mass spectrometry (GC-MS) operating in scan mode. The main authentication markers identified in traditional beer were from aromatic compounds, aldehydes and alcohol esters. The most predominant authentication marker compounds in beer flavored with Magnum hop essential oil were obtained from terpenoids, followed by acid esters, alcohol esters and alcohol classes. A unique feature of this study was represented by the discriminant markers for the authentication of Magnum hop variety, identified in hop pellets, hop essential oil and flavored beer. The application of this methodology can be used for optimization of brewing technology and process parameters in view of prolonging fruity hop flavor stability of Romanian beers.

KEYWORDS:

• Authentication marker compounds
• gas-chromatography-mass spectrometry (GC-MS)
• hops
• in-tube extraction (ITEX)
• primary beer fermentation