Determinação espectrofotométrica do teor de polifenóis de diferentes cultivares de Humulus lupulus adaptadas ao Cerrado

Abstract

Hops (Humulus lupulus L.) are an essential raw material for the brewing industry, responsible for imparting bitterness, aroma, and microbiological stability to beer through their secondary metabolites, as well as contributing to its chemical and sensory stability. Despite being one of the largest beer producers in the world, Brazil remains highly dependent on imported hops. This study aimed to analyze the total polyphenol content in different hop cultivars grown under environmental conditions of the Brazilian Cerrado. The methodology was based on internationally recognized analytical protocols, using the colorimetric method standardized by the European Brewery Convention (EBC 7.14) for polyphenol determination. From a chemical standpoint, the quantification of these compounds is based on the formation of colored complexes between phenolic hydroxyl groups and ferric ions (Fe³⁺) in an alkaline medium, with absorbance measured at 600 nm using UV-Vis spectrophotometry. The results showed differences in total polyphenol content among the three hop cultivars analyzed, even when cultivated under the same environmental conditions. The Triple Pearl cultivar presented the highest total polyphenol content (5.08 ± 0.38%), followed by Zeus (3.00 ± 0.08%), while Comet showed the lowest value (2.48 ± 0.22%). This variation indicates the influence of genetic factors on the biosynthesis of phenolic compounds, even under the same cultivation conditions. The values obtained are within the same order of magnitude as those reported in the literature for hops grown in traditional regions and other areas, suggesting that tropical conditions in the Cerrado do not prevent the formation of these secondary metabolites. Thus, the chemical characterization of total polyphenols indicates the technical feasibility of hop cultivation under tropical climate conditions and reinforces the potential of this raw material for application in the brewing industry, contributing to the strengthening of national production and the reduction of dependence on imported hops.