Beer is one of the oldest and most widely consumed beverages in the world, It has a complex
chemical composition characterized by amino acids, carbohydrates, minerals, and vitamins.
The beverage also contributes to prevent a number of health-related problems, in addition to
the constant search for innovations in the brewing industry. When combined with the nutritional
and medicinal benefits of Kefir, the beverage has anti-inflammatory and anti-ulcerogenic
activities. Based on this, the present work sought to analyze the chemical profile of a new beer
fermented by Kefir grains by GC-MS and HPLC-DAD and make the comparison with
conventional beer. For the study, three hind of beer samples were produced, one conventional,
one fermented with Kefir grains at room temperature and another at controlled temperature, in
order to verify the chemical composition of each one. The beers with Kefir had lower alcohol
content than the conventional Barley Wine, being respectively 7.3% and 8.9%. The extraction
of the compounds was done by HS-SPME, which proved to be very promising because it is a
simple and sensitive technique that does not use solvents. Thirteen compounds were identified
in the Kefir, being acetoin and acetic acid the most abundant. Similarly, 18 compounds were
found in the beer, being ethanol, ethyl acetate, isopentyl alcohol and isopentyl acetate the most
abundant. However, the conventional beer presented 4 fewer compounds compared to those
with Kefir, showing that the probiotic beers have a richer chemical profile. By extraction of the
fractions by SPE, it was found that the beers had hydrophilic compounds, highlighting the style
of beer adopted, and the presence of phenolic compounds such as flavonoids, including rutin
and quercetin. It was verified that despite the difference in the yeast used, the chromatographic
profiles were very similar, i.e., even changing the form of fermentation the same product, beer,
was obtained. Finally, by means of statistical analysis, PCA, HCA and PLS-DA, it was found
that the beers fermented with Kefir grains had greater similarity between them than with
conventional beer.
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