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Influence of pre-drying storage time on essential oil components in dried hops (Humulus lupulus L.)

BACKGROUND 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. RESULTS 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 R²adj 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. CONCLUSION 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.

Sponsor
Gefördert im Rahmen des Projekts DEAL
Citation
In: Journal of the Science of Food and Agriculture Volume 101 / Issue 6 (2020-10-15) , S. 2247-2255; eissn:1097-0010
Collections
@article{doi:10.17170/kobra-202107054245,
  author    ={Raut, Sharvari and von Gersdorff, Gardis Johanna Elisabeth and Münsterer, Jakob and Kammhuber, Klaus and Hensel, Oliver and Sturm, Barbara},
  title    ={Influence of pre-drying storage time on essential oil components in dried hops (Humulus lupulus L.)},
  keywords ={500 and 580 and Hopfen and Trocknung and Gaschromatographie and Lagerung and Feuchtigkeit and Etherisches Öl},
  copyright  ={http://creativecommons.org/licenses/by/4.0/},
  language ={en},
  journal  ={Journal of the Science of Food and Agriculture},
  year   ={2020-10-15}
}