Analysis of mousy off-flavor compound 2-Acetyl-tetrahydropyridine using Liquid Chromatography Mass Spectrometry with Electrospray Ionization in sour beer

Paulina Martusevice; Xueqi Li; Matt Hengel; Selina C Wang; Glen Fox

doi:10.1016/j.mex.2024.102643

Analysis of mousy off-flavor compound 2-Acetyl-tetrahydropyridine using Liquid Chromatography Mass Spectrometry with Electrospray Ionization in sour beer

MethodsX. 2024 Mar 5:12:102643. doi: 10.1016/j.mex.2024.102643. eCollection 2024 Jun.

Authors

Paulina Martusevice^{1

2

3}, Xueqi Li¹, Matt Hengel⁴, Selina C Wang¹, Glen Fox¹

Affiliations

¹ Department of Food Science and Technology, University of California, Davis, CA, United States.
² Lithuanian Research Centre for Agriculture and Forestry, Institute of Horticulture, Kaunas, Lithuania.
³ Vytautas Magnus University, Botanical Garden, Kaunas, Lithuania.
⁴ Department of Environmental Toxicology, University of California, Davis, CA, United States.

Abstract

Mousy off-flavor describes N-heterocycles compounds related to spoilage in the brewing industry. It has also been identified in sour beers through sensory analysis. Therefore, preventing spoilage N-heterocycles development is essential to preserve end-products and obviate economic losses. To this day, no methods or protocols have been reported to identifying mousy off-flavor compounds in a beer matrix. The main objective of this work was to develop a standardized quantification method for 2-acetyl-3,4,5,6-tetrahydropyridine (ATHP) in beer matrix, by Liquid Chromatography Mass Spectrometry with Electrospray Ionization (LC-MS-ESI). Extraction of ATHP in the samples was performed using QuEChERS (quick, easy, cheap, effective, rugged, and safe) technique. Over a dozen different potentially mousy cask-aged sour beers including other spontaneously fermented beverages were provided, based on sensory analysis, to determine the variation in ATHP levels. Results indicated ATHP was found in all the samples, ranging from 1.64 ± 0.06 to 57.96 ± 2.15 µg L^-1. Herein, we described our detection method of mousy-off flavor compounds which enables future research to mitigate the occurrence of such defects in fermented beverages matrix.•ATHP content in samples varied from 1.64 ± 0.06 to 57.96 ± 2.15 µg L^-1.•The recovery range of ATHP using LC-MS-ESI varied from 71% to 97%.•Basified QuEChERS salting-out procedure is applicable for ATHP extraction from beer and other fermented beverages matrices.

Keywords: 2-Acetyl-3,4,5,6-tetrahydropyridine (ATHP); Liquid Chromatography Mass Spectrometry with Electrospray Ionization (LC-MS-ESI); Mousy off-flavor; QuEChERS; Quantitative analysis of 2-Acetyl-tetrahydropyridine using Liquid Chromatography Mass Spectrometry with Electrospray Ionization; Sour beer.