resumo
Beer stability is a major concern for the brewing industry, as beer characteristics may be subject to significant changes during storage. This paper describes a novel non-targeted methodology for monitoring the chemical changes occurring in a lager beer exposed to accelerated aging (induced by thermal treatment: 18 days at 45 degrees C), using gas chromatography-mass spectrometry in tandem with multivariate analysis (GC-MS/MVA). Optimization of the chromatographic run was performed, achieving a threefold reduction of the chromatographic time. Although losing optimum resolution, rapid GC runs showed similar chromatographic profiles and semi-quantitative ability to characterize volatile compounds. To evaluate the variations on the global volatile signature (chromatographic profile and m/z pattern of fragmentation in each scan) of beer during thermal deterioration, a non-supervised multivariate analysis method, Principal Component Analysis (PCA), was applied to the GC-MS data. This methodology allowed not only the rapid identification of the degree of deterioration affecting beer, but also the identification of specific compounds of relevance to the thermal deterioration process of beer, both well established markers such as 5-hydroxymethylfufural (5-HMF), furfural and diethyl succinate, as well as other compounds, to our knowledge, newly correlated to beer aging. (C) 2010 Elsevier B.V. All rights reserved.
palavras-chave
FURFURYL ETHYL ETHER; BETA-DAMASCENONE; FLAVOR STABILITY; LIQUID-CHROMATOGRAPHY; DIMETHYL TRISULFIDE; REDUCING POWER; UV DETECTION; LAGER BEER; PH; SPECTROMETRY
categoria
Biochemistry & Molecular Biology; Chemistry
autores
Rodrigues, JA; Barros, AS; Carvalho, B; Brandao, T; Gil, AM; Ferreira, ACS
nossos autores
agradecimentos
The authors acknowledge the Portuguese Foundation for Science and Technology for funding through the FCT SFRH/BD/31056/2006 Grant.