Comparison between pentane, hexane and SCO2 extraction of Brazilian comet hops

Brazil is the third-largest beer producer in the world, but it imports almost all of the hops it needs to produce beer. Recently, farmers have been using light supplementation to modulate the photoperiod and make hop cultivation possible. Most hops used in the industry are in extract form, with supercritical CO₂  being a clean and efficient method for producing extracts with high concentrations of alpha- and beta- acids. Brazilian Hops of the Comet variety were evaluated for extraction yield and bitter-acid composition using Soxhlet with hexane and pentane, and supercritical CO₂ (40 °C, 150 bar). The objective was to compare extraction yield and α- and β-acid contents among the three extraction methods. Samples were processed and analyzed spectrophotometrically using the ASBC method. Results for hexane were α-acids = 32.4 ± 3.03, β-acids = 15.81 ± 3.69, yield = 22.64 ± 1.71; pentane α-acids = 46.85 ± 13.25, β-acids = 9.88 ± 8.65, yield = 19.31 ± 0.75; supercritical CO₂ α-acids = 41.94 ± 10.54, β-acids = 29.52 ± 5.03, yield = 16.29 ± 0.41. Statistical analysis by one-way ANOVA found no significant difference in α-acids across methods (p = 0.288), whereas β-acids differed significantly (p = 0.021); Tukey post-hoc comparisons indicated the β content of CO₂ extracts was significantly higher than that of pentane (p = 0.02). Extraction yields were significantly different (p=0.001). Tukey's test showed that the yields of hexane were higher than those of pentane, which in turn were greater than those of supercritical CO₂ . Supercritical CO₂ produced extracts richer in β-acids, while hexane Soxhlet delivered the highest extraction yield, followed by pentane, which was expected since it was an exhaustive extraction. However, the yield and purity of the CO₂ extract indicate quality, which is corroborated by its color, since the extracts made with organic solvents had a greenish coloration indicating chlorophyll extraction, while the supercritical one had an orange coloration. Further work with greater sample size and controlled processing is recommended to confirm these patterns and to optimize extraction parameters for Brazilian Comet hops.