Department of Agricultural and Biosystems Engineering, University of Kassel, Witzenhausen, Germany.
Bavarian State Research Center for Agriculture (LfL), Hop Competence Centre Production Technologies, Wolnzach, Germany.
J Sci Food Agric. 2021 Apr;101(6):2247-2255. doi: 10.1002/jsfa.10844. Epub 2020 Oct 15.
It is well known that duration of pre-drying storage impacts on hop quality. However, little knowledge exists regarding its actual effects on valuable hop components. To investigate these effects, fresh hop cones were stored for 5 or 24 h and dried for 210 min at 65 °C thereafter. Furthermore, to understand the effect of freezing hop cones on the essential oil content, both fresh and stored samples were frozen before and after drying.
The results from gas chromatography analysis show an increase in linalool, β-caryophyllene, humulene, geraniol content and decrease in myrcene content dependent on the period of storage. Total colour difference ΔE values of 4.61 and 5.27 were obtained for fresh and stored hops respectively, indicating discoloration of hops during storage. Modelling of moisture curves revealed the Wang and Singh model to be suitable, with values of 0.978 and 0.989 and root-mean-square error values of 0.037 and 0.019 for fresh and stored hops respectively.
The results from this study provide an in-depth understanding on the changes occurring within the hop cones both during storage and drying and will further help hop processors optimize their storage times.
众所周知，预干燥储存时间会影响啤酒花的质量。然而，对于其对有价值的啤酒花成分的实际影响，我们知之甚少。为了研究这些影响，我们将新鲜的啤酒花球果储存 5 或 24 小时，然后在 65°C 下干燥 210 分钟。此外，为了了解冷冻啤酒花球果对精油含量的影响，我们在干燥前后对新鲜和储存的样品进行了冷冻。
气相色谱分析的结果表明，随着储存时间的延长，芳樟醇、β-石竹烯、葎草烯、香叶醇的含量增加，月桂烯的含量减少。新鲜和储存的啤酒花的总色差ΔE 值分别为 4.61 和 5.27，表明啤酒花在储存过程中会变色。水分曲线的建模表明，Wang 和 Singh 模型是合适的，新鲜和储存的啤酒花的 值分别为 0.978 和 0.989，均方根误差值分别为 0.037 和 0.019。
本研究的结果深入了解了啤酒花球果在储存和干燥过程中发生的变化，这将进一步帮助啤酒花加工商优化其储存时间。
