Hop Utilization in the Brewery—An Interbrewery Comparison

Quantitative Sensomics Profiling of Hop-Derived Bitter Compounds Throughout a Full-Scale Beer Manufacturing Process

“…Interestingly, the decreasing concentrations of hulupones during beer processing were not accompanied by an accelerated formation of hulupinic acid (36). These findings give first evidence that in contradiction to literature data (13), the degradation of hulupones does not lead exclusively to the formation of hulupinic acid (36), and further unknown pathways contribute to the decrease of hulupones (18)(19)(20) in beer.…”

“…High concentrations of xanthohumol (1), the R-acids 3-5, as well as the β-acids 15-17 were detectable in both hop products but, as to be expected, the amounts of any isomerization and/or degradation products such as, for example, isoxanthohumol (2), iso-R-acids (6-11), or hulupones (18)(19)(20) in these samples were below the detection limit of the HPLC-MS/MS method used. The hop extract, made from the two bitter hop varieties Magnum and Taurus, was found to be rich in R-acids and contained 19.92% humulone (4), 10.66% cohumulone (3), and 6.36% adhumulone (5), respectively ( Table 2).…”

“…To avoid negative or exaggerated estimates at the low end of the concentration ranges, the functions were forced through zero, thus leading to correlation coefficients of >0.99 for all the reference compounds. The iso-R-acids (6-11) were quantitated using the calibration curve of their isomer 6, the n-and ad-congeners of R-acids (4, 5), β-acids (16,17), humulinones (13,14), hulupones (19,20), and tricyclohumols (38, 39) were analyzed on the basis of the calibration curve of the corresponding cocongener (3,15,12,18,37). The tricyclic β-acid degradation products (21-35b) were analyzed using nortricyclocolupone (21) as the external standard.…”

“…In addition, the decrease of the pH value from 5.4 in the wort to 4.3 ( Table 3) after fermentation might impact the solubility of the R-acids (18,27,28).…”

“…Reaction routes for the transformation of the hop-derived bitter compounds xanthohumol (1), R-acids(3)(4)(5), and β-acids (15-17) upon beer manufacturing leading to the formation of isoxanthohumol (2), trans-and cis-iso-R-acids (6-11), humulinones(12)(13)(14), hulupones(18)(19)(20), tricyclic β-acid cyclization products (21-35), hulupinic acid (36), tricyclohumols (37-39), cis-and trans-humulinic acids (40-45), cis-and trans-alloisohumulonehydroxides (46-51), and the corresponding -hydroperoxides (52-57).…”