Web Release Date: January 13,
Composition of Beer by 1H NMR Spectroscopy: Effects of Brewing Site and Date of Production
and
CICECO and QOPNAA, Department of Chemistry, Campus Universitário de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal, and Bruker Biospin GmbH, Silberstreifen, D76287 Rheinstetten, Germany
Received for review October 31, 2005. Accepted December 8, 2005. C.A. thanks Bruker Biospin for funding support, and I.F.D. thanks the Foundation for Science and Technology, Portugal, for funding support through the Grants PRAXIS/BD/15666/98 and SFRH/BPD/11516/2002 within the III Community framework.
Abstract:
A principal component analysis (PCA) of 1H NMR spectra of beers differing in production site (A, B, C) and date is described, to obtain information about composition variability. First, lactic and pyruvic acids contents were found to vary significantly between production sites, good reproducibility between dates being found for site A but not for sites B and C beers. Second, site B beers were clearly distinguished by the predominance of linear dextrins, while A and C beers were richer in branched dextrins. Carbohydrate reproducibility between dates is poorer for site C with dextrin branching degree varying significantly. Finally, all production sites were successfully distinguished by their contents in adenosine/inosine, uridine, tyrosine/tyrosol, and 2-phenylethanol, reproducibility between dates being again poorer for site C. Interpretation of the above compositional differences is discussed in terms of the biochemistry taking place during brewing, and possible applications of the method in brewing process control are envisaged.
Keywords: Beer; analysis; origin; quality control; NMR; spectroscopy
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