Determination of Hop Aroma Compounds in Beer Using Headspace-Solid Phase Microextraction Coupled with Gas Chromatography and Mass Spectrometry (HS/SPME/GC/MS)

Abstract

Hop aroma compounds, such as β-myrcene, linalool, and geraniol, play a very important role as indexes for beer flavor and process control. However, since they comprise many compounds with different physical properties and their concentration in beer is low, their simultaneous analysis has been a difficult task in the past, resulting in no method being proposed for inclusion in the Methods of Analysis of BCOJ. We propose a method for simultaneously analyzing the low-concentration compounds in beer using HS/SPME/GC/MS as one of the potential Methods of Analysis of BCOJ and evaluated its concurrent accuracy and inter-room repeatability and reproducibility. The collaborative work was conducted in 12 laboratories in Japan. The statistical summary of results is as follows: The relative standard deviation of repeatability (RSDr) ranged from 4.8 to 20.3% for β-myrcene, 3.7 to 5.2% for linalool, and 5.7 to 9.6% for geraniol; and the repeatability at 95% probability (r95) ranged from 1.5 to 15.3 µg/L for β-myrcene, 2.7 to 6.2 µg/L for linalool, and 0.7 to 2.1 µg/L for geraniol. The relative standard deviation of reproducibility (RSDR) ranged from 11.0 to 41.2% for β-myrcene, 8.1 to 11.6% for linalool, and 12.7 to 25.8% for geraniol; and the reproducibility at 95% probability (R95) ranged from 3.4 to 22.8 µg/L for β-myrcene, 5.6 to 15.6 µg/L for linalool, and 2.7 to 4.3 µg/L for geraniol. The obtained results were deemed acceptable. It was concluded that the method can determine hop aroma compounds in beer, low-malt beer, and third-category beer.