Caracterização química de cervejas ácidas com adição de frutas por ressonância magnética nuclear de hidrogênio

Abstract

This work enable the identification of presence of 30 different organic species in sour beers with added fruits, based on the signals from Hydrogen Nuclear Magnetic Resonance 1H-NMR spectra.. It was possible to identify the profile of organic acids (lactic, acetic, 4-aminobutyric, pyruvic, succinic, citric, gallic, and formic) characteristic of this type of beer analyzed, in addition to sugars, alcohols, amino acids, and other compounds typical of traditional beers. Only 500 μL of previously degassed sour beers, without solids and buffered were mixed with 100 μL of 3-trimethylsilyl-2,3,3,3 propionate-d4 sodium (TSP-d4) solution in D2O for analysis in a 600 MHz NMR spectrometer. The obtained spectral signals were pre-processed with the icoshift and bucketing algorithms and were satisfactorily aligned for subsequent unsupervised exploratory chemometric analysis (PCA). Through this analysis, it was possible to discriminate the analyzed samples based on their chemical profile and also to identify which signals were responsible for discriminating the analyzed samples. The use of exploratory analysis of spectral data also allowed the observation that data discrimination mainly occurs according to the class of beers declared by the manufacturer: sour and sour Catharina. These beers are primarily discriminated by the differences in NMR signals related to lactic, acetic, succinic acid, butan-2,3-diol, ethanol, and sugars. These results demonstrate that chemometric analysis of H-NMR spectra is a powerful tool for characterizing and discriminating sour beers, providing a detailed understanding of their specific chemical profiles.