NMR and Chemometrics in the Determination of Chemical Profiles for the Distinction of Brazilian Ale and Lager Beers

Abstract

Determining chemical profiles of complex matrices, such as beers of different styles, can highlight regional characteristics and provide robust literature on the variability of this product, improving quality control. A practical application is to unequivocally attribute the authenticity of the product even in the face of variations in composition due to inadequate transport and storage. This work used proton nuclear magnetic resonance (1 H NMR) spectroscopy and chemometrics in the semi-quantitative study of Brazilian ale and lager beers. The results demonstrated the success of applying 1 H NMR in characterizing chemical profiles and as a statistical database to distinguish ale and lager beers. Using principal component analysis (PCA) of the NMR data, it was possible to identify that carbohydrate content was responsible for the separation tendency between these beer styles. Ale beers had a higher residual carbohydrate content, according to the integrals of the carbohydrate hydrogens. This is expected, as these beers are obtained by fermentation at higher temperatures for shorter fermentation times. The paper also described soft independent modelling of class analogies (SIMCA) as applied to the NMR data. This class model made it possible to correctly classify 90% of the samples as ale and 100% as lager.