Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan.
Zhangmen Brewing Company, New Taipei City 22161, Taiwan.
J Am Soc Mass Spectrom. 2024 Apr 3;35(4):746-755. doi: 10.1021/jasms.3c00439. Epub 2024 Feb 29.
Hops ( L.) are essential raw materials for beer brewing, and the major contributors to beer bitterness are isohumulones (iso-α-acids) and humulinones. In recent years, many breweries have focused on the production of hop-forward beer styles by adding hops after or during the cold fermentation stage, which will tend to release humulinones or other hop-derived bitter compounds. In this study, a LC-MS/MS method was developed for quantification of 60 hop-derived bitter compounds in 25 min. Reverse-phase chromatography with an alkaline methanol/acetonitrile (70:30) mobile phase was used for the separation. The quantitative range was 0.053-3912 ng/mL with correlation coefficient > 0.99, and the LOQ were 0.26 and 0.053 ng/mL for iso-α-acids and humulinones. Precision (RSD < 5.0%) and accuracy (recovery 86.3%-118.1%) were both satisfactory. The abundance of hop-derived bitter compounds in the dry-hopped beer (Double-India Pale Ale) and the nondry-hopped beer (Vienna Lager) were monitored throughout the fermentation and storage stages, and the formation of oxidation and cyclization products showed difference profiles between these two beers. The quantification results reveal how hop-derived bitter compounds change throughout the brewing process, as well as the influence of hops and brewing techniques on beer bitterness.
啤酒花（L.）是啤酒酿造的重要原料，啤酒苦味的主要贡献者是异α-酸（iso-α-acids）和合葎草酮。近年来，许多啤酒厂专注于生产后或在冷发酵阶段添加啤酒花的高酒花啤酒风格，这将倾向于释放合葎草酮或其他源自啤酒花的苦味化合物。在这项研究中，建立了一种在 25 分钟内定量分析 60 种源自啤酒花的苦味化合物的 LC-MS/MS 方法。使用碱性甲醇/乙腈（70:30）流动相的反相色谱法进行分离。定量范围为 0.053-3912 ng/mL，相关系数 >0.99，iso-α-acids 和合葎草酮的 LOQ 分别为 0.26 和 0.053 ng/mL。精密度（RSD <5.0%）和准确度（回收率 86.3%-118.1%）均令人满意。在整个发酵和储存阶段监测了干投啤酒（双倍印度淡色艾尔）和非干投啤酒（维也纳拉格）中源自啤酒花的苦味化合物的丰度，并且氧化和环化产物的形成显示出这两种啤酒之间的差异。定量结果揭示了源自啤酒花的苦味化合物在酿造过程中的变化情况，以及啤酒花和酿造技术对啤酒苦味的影响。
