Table of Contents
Determination of Variety Dependent “Thiol Impact” Based on LC-MS/MS Analysis of Different Hop Samples Collected Worldwide
Christina Schmidt, Laura Hoferer and Martin Biendl
Certain volatile thiols are some of the most potent odour-active molecules found in food and beverages including beer. Even contents of a few µg/kg in hops can be high enough to finally result in significant contributions to beer flavour, especially after dry hopping. Most published methods for the determination of free thiols in hops are based on gas chromatographic measurements. However, liquid chromatography in combination with tandem mass spectrometry (LC-MS/MS), as presented in this study, can also serve for their reliable quantification. This method was used to quantify 4-mercapto-4-methylpentan-2-one (4MMP), 3-mercaptohexan-1-ol (3MH), and 3-mercapto-4-methylpentan-1-ol (3M4MP) in 250 hop samples of 97 different varieties from 12 countries and 5 crop years (2019 – 2023). Thiol contents show high fluctuation ranges not only dependent on the variety but also on growing area, crop year or harvest date. Based on a large number of single results, it is suggested to create a general classification of varieties by assigning three main categories (low/medium/high) for their “thiol impact” in beer brewing.
Descriptors: Free polyfunctional thiols, thiol impact, hops, beer brewing
BrewingScience, 77 (November/December 2024), pp. 135-141