Kvasny Prum. 2011; 57(7-8): 266-271 | DOI: 10.18832/kp2011030

Hop essential oils in the selected varieties from differently old hop yards.Peer-reviewed article

Helena PLUHÁČKOVÁ, Jaroslava EHRENBERGEROVÁ, Pavel KRETEK, Blanka KOCOURKOVÁ

Mendelova univerzita v Brně, Zemědělská 1, 613 00 Brno

The aim of this study was to evaluate properties of hop cones from differently old hop yards in the varieties grown in Tršice hop-growing region. The following varieties were assessed: Saaz semi-early red bine hop - traditional form, Saaz semi-early red bine hop - recovered form ozdravená, and the varieties Premiant and Sládek. Hop cones were collected during harvest in 2009 and 2010. Cones sampling was performed according to the general sampling principles. Contents of foreign and hop admixtures were determined in an average sample pursuant to the ČSN 462520 - 4 and 5. In addition, essential oil content in hop cones was assessed using water steam distillation after the method described by Krofta. This method was modified to our requirements and a distillation apparatus for the determination of essential oils in plant drugs according to Český lékopis 2009/List of medical products 2009 was used. The varieties were assessed individually regarding a different age of hop yards. In addition, yield of hop cones was evaluated. Results show differences in yields, contents of hop admixtures and essential oil. Yield of the variety Saaz semi-early red bine hop - traditional form was higher in both differently old hop yards in 2010. Content of admixtures was higher in 2009 compared to 2010. Essential oil content in both years was lower in older hop yards. In the variety Saaz semi-early red bine hop - recovered form, the highest yields were in the 15-year-old hop yard and the lowest in the youngest (9-year-old) hop yard in 2009 and 2010. The lowest admixture contents in 2009 were detected in samples from the youngest hop yards (9 and 10 year-old) and the highest values in samples from the older hop yards (12 to 17 year-old). This trend was similar in 2010. Clear tendency to decline in essential oil content depending on the hop yard age was recorded. The variety Sládek provided the lowest yield in the younger hop yards and higher in the older ones. Admixture content in 2009 declined depending on the age of a hop yard, with the exception of a seven-year-old hop yard. On the contrary, in 2010 admixture content increased in dependence on age, it was lower only in an eight-year-old hop yard. In both years essential oil content was the highest in the youngest hop yard and then it declined depending on the hop yard age.The aim of this study was to evaluate properties of hop cones from differently old hop yards in the varieties grown in Tršice hop-growing region. The following varieties were assessed: Saaz semi-early red bine hop - traditional form, Saaz semi-early red bine hop - recovered form ozdravená, and the varieties Premiant and Sládek. Hop cones were collected during harvest in 2009 and 2010. Cones sampling was performed according to the general sampling principles. Contents of foreign and hop admixtures were determined in an average sample pursuant to the ČSN 462520 - 4 and 5. In addition, essential oil content in hop cones was assessed using water steam distillation after the method described by Krofta. This method was modified to our requirements and a distillation apparatus for the determination of essential oils in plant drugs according to Český lékopis 2009/List of medical products 2009 was used. The varieties were assessed individually regarding a different age of hop yards. In addition, yield of hop cones was evaluated. Results show differences in yields, contents of hop admixtures and essential oil. Yield of the variety Saaz semi-early red bine hop - traditional form was higher in both differently old hop yards in 2010. Content of admixtures was higher in 2009 compared to 2010. Essential oil content in both years was lower in older hop yards. In the variety Saaz semi-early red bine hop - recovered form, the highest yields were in the 15-year-old hop yard and the lowest in the youngest (9-year-old) hop yard in 2009 and 2010. The lowest admixture contents in 2009 were detected in samples from the youngest hop yards (9 and 10 year-old) and the highest values in samples from the older hop yards (12 to 17 year-old). This trend was similar in 2010. Clear tendency to decline in essential oil content depending on the hop yard age was recorded. The variety Sládek provided the lowest yield in the younger hop yards and higher in the older ones. Admixture content in 2009 declined depending on the age of a hop yard, with the exception of a seven-year-old hop yard. On the contrary, in 2010 admixture content increased in dependence on age, it was lower only in an eight-year-old hop yard. In both years essential oil content was the highest in the youngest hop yard and then it declined depending on the hop yard age.

Keywords: biological admixtures, yield, essential oil content, hop yard age

Received: May 25, 2011; Accepted: June 20, 2011; Published: July 1, 2011