Application of NMR and Chemometrics for the Profiling and Classification of Ale and Lager American Craft Beer.

Morgan Vasas,Fenfen Tang,Emmanuel Hatzakis

doi:10.3390/foods10040807

Abstract

In this paper, Nuclear Magnetic Resonance spectroscopy (NMR)-based metabolomics were applied for the discrimination of ale and lager craft American beers. A modified pulse sequence that allows the efficient suppression of the water and ethanol peaks was used to achieve high-quality spectra with minimal sample preparation. The initial chemometrics analysis generated models of low predictive power, indicating the high variability in the groups. Due to this variability, we tested the effect of various data pretreatment and chemometrics approaches to improve the model’s performance. Spectral alignment was found to improve the classification significantly, while the type of normalization also played an important role. NMR combined with statistical and machine-learning techniques such as orthogonal projection to latent structures discriminant analysis (OPLS-DA) and random forest was able to discriminate between ale and lager beers, thus providing an important tool for the quality control and analysis of these products.

Highlights

Beer is a popular beverage throughout the world
Water signal. because hydrogen chemical exchange between water and ethanol generates a broad water In a pseteapk,awt δe4.a8p, pwlhieicdh trhedisucmesetthheodeffifocirenthcye oafnWalEyTsiisn osuf plapgreesrsianngdthaelwe actrearfstigbneaelr
We evaluated the impact of the sample normalization method on the orthogonal projection to latent structures discriminant analysis (OPLS-DA) model’s performance

Summary

Introduction

Beer is a popular beverage throughout the world. It has a significant impact on both economy and human society. Beers exist in many varieties; they are commonly categorized into two discrete groups, i.e., top- and bottom-fermented beers, known as ales and lagers, respectively. This classification is drawn from the strain of yeast utilized in the fermentation process and its behavior within the fermentation tank. Bottom fermentation, associated with the production of lager-type beers, involves the yeast Saccharomyces pastorianus that typically sinks to the bottom of the tank during fermentation [1]

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Conclusion