Microwave-Assisted Hydrodistillation of Hop (Humulus lupulus L.) Terpenes: A Pilot-Scale Study

Interest in essential oils has consistently increased in recent years. Essential oils have a large variety of applications in multiple fields, including in the food, cosmetics and pharmaceutical industries. The volatile fraction (VF) in hops (Humulus lupulus L.) fits within this domain as it is primarily used in the brewery industry for the aromatization of beer, and is responsible for the floral and fruity tones. This work aims to design an optimized extraction protocol of the VF from hops, using microwaves. Microwave-assisted hydrodistillation (MAHD) has been developed to reduce energy and time consumption in lab-scale reactors up to industrial-scale systems. Hops are principally available in three forms, according to a brewery’s applications: (i) fresh (FH); (ii) dried (DH) and (iii) pelletized (PH). In this work, all three forms have therefore been studied and the recovered volatiles characterized by means of GC-MS. The optimized lab-scale MAHD protocol gave the best extraction yield of 20.5 mLVF/kgdry matrix for FH. This value underwent a slight contraction when working at the highest matrix amount (3 kg), with 17.3 mLVF/kgdry matrix being achieved. Further tests were then performed in a pilot reactor that is able to process 30 kg of material. In this case, high yield increases were observed for PH and DH; quadruple and double the lab-scale yields, respectively. In addition, this industrial-scale system also provided marked energy savings, practically halving the absorbed kJ/mLVF.

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Assessment of the Suitability of Aromatic and High-Bitter Hop Varieties (Humulus lupulus L.) for Beer Production in the Conditions of the Małopolska Vistula Gorge Region

Fermentation ◽

10.3390/fermentation7030104 ◽

2021 ◽

Vol 7 (3) ◽

pp. 104

Author(s):

Barbara Sawicka ◽

Mateusz Śpiewak ◽

Anna Kiełtyka-Dadasiewicz ◽

Dominika Skiba ◽

Bernadetta Bienia ◽

...

Keyword(s):

Physicochemical Properties ◽

Essential Oils ◽

Humulus Lupulus ◽

High Yield ◽

Brewing Industry ◽

Monoterpene Hydrocarbons ◽

Humulus Lupulus L ◽

Beer Production

The aim of the study was to assess the yield of cones and the quality of six hop varieties (“Iunga”, “Lubelski”, “Sybilla”, “Magnum”, “Lomik”, “Marynka”) in terms of their suitability for beer production, under the conditions of the Małopolska Vistula Gorge Region (21°53′ E; 51°16′ N) (2015–2017). The scope of the research included the determination of the yield of cones and their physicochemical properties, as well as determination of the contents of hop resins and essential oils. In bitter varieties, the ratio of alpha-acids to beta-acids was stable, while, in aromatic varieties, it was variable. In the essential oils of the studied hop varieties, compounds with myrcene and α-humulene were identified and dominated the profiles. “Iunga”, “Sybilla”, “Lubelski”, and “Lomik” were rich in monoterpene hydrocarbons, mainly myrcene, while there was a bit more α-humulene in the “Marynka” variety. “Magnum” was characterized by an even distribution of monoterpenes and sesquiterpenes. The “Magnum variety turned out the most useful for the brewing industry in this region. The Małopolska Vistula Gorge Region is a region where hops not only achieve a high yield of cones, but also good-quality. The bitterness and aroma content of the hops in this region is high.

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Composition of the essential oils from leaves of various Humulus lupulus L. cultivars

Flavour and Fragrance Journal ◽

10.1002/ffj.2730050208 ◽

1990 ◽

Vol 5 (2) ◽

pp. 97-100 ◽

Cited By ~ 13

Author(s):

S. T. Katsiotis ◽

C. R. Langezaal ◽

J. J. C. Scheffer

Keyword(s):

Essential Oils ◽

Humulus Lupulus ◽

Humulus Lupulus L

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Comparative Gas Chromatographic–Mass Spectrometric Evaluation of Hop (Humulus lupulus L.) Essential Oils and Extracts Obtained Using Different Sample Preparation Methods

Food Analytical Methods ◽

10.1007/s12161-013-9767-5 ◽

2013 ◽

Vol 7 (7) ◽

pp. 1433-1442 ◽

Cited By ~ 21

Author(s):

Magdalena Ligor ◽

Mantas Stankevičius ◽

Anna Wenda-Piesik ◽

Kęstutis Obelevičius ◽

Ona Ragažinskienė ◽

...

Keyword(s):

Sample Preparation ◽

Essential Oils ◽

Humulus Lupulus ◽

Mass Spectrometric ◽

Preparation Methods ◽

Humulus Lupulus L ◽

Sample Preparation Methods ◽

Chromatographic Mass

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New fine aroma varieties of hops (Humulus lupulus L.) Saaz Brilliant, Saaz Comfort, Saaz Shine and Mimosa

KVASNY PRUMYSL ◽

10.18832/kp2019.66.320 ◽

2020 ◽

Vol 66 (4) ◽

pp. 320-330

Author(s):

Vladimír Nesvadba ◽

Jitka Charvátová

Keyword(s):

Czech Republic ◽

Essential Oils ◽

Acid Content ◽

Humulus Lupulus ◽

The Other ◽

The Czech Republic ◽

Humulus Lupulus L

Four new aroma hop varieties – Saaz Brilliant, Saaz Comfort, Saaz Shine and Mimosa – were registered in the Czech Republic in 2019. All of the new hop varieties have significantly higher yields than the traditional Saaz aroma variety. Saaz Comfort has the significantly highest content of alpha acids (5.59%) whereas Mimosa has the significantly lowest content of alpha acids (1.90%). The Saaz Comfort and Saaz Brilliant varieties show a variability of alpha acid content below 20%. The other hop varieties, Saaz Shine and Mimosa, as well as Saaz, have a variability of alpha acid content above 25%. Mimosa has the significantly highest content of beta acids (6.07%). Mimosa shows the highest average cohumulone content (29.29% rel.) whereas Saaz Comfort has the lowest cohumulone content (18.04% rel.). Saaz Comfort and Saaz Shine have the highest average contents of hop essential oils (0.84% w. and 0.75% w., respectively). The Saaz, Saaz Shine and Saaz Brilliant varieties show the significantly highest farnesene contents (13.47% rel., 12.50% rel. and 12.38% rel., respectively), which are higher than those of Saaz Comfort and Mimosa.

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Essential Oils from Humulus Lupulus scCO2 Extract by Hydrodistillation and Microwave-Assisted Hydrodistillation

Molecules ◽

10.3390/molecules23112866 ◽

2018 ◽

Vol 23 (11) ◽

pp. 2866 ◽

Cited By ~ 10

Author(s):

Katarzyna Tyśkiewicz ◽

Roman Gieysztor ◽

Marcin Konkol ◽

Jan Szałas ◽

Edward Rój

Keyword(s):

Essential Oils ◽

Extraction Methods ◽

Humulus Lupulus ◽

Raw Material ◽

Diode Array ◽

Diode Array Detection ◽

Microwave Assisted ◽

Array Detection ◽

Essential Oil Production

Two different extraction methods were used for a comparative study of essential oils obtained from the Humulus lupulus scCO2 (sc-supercritical) extract: microwave-assisted hydrodistillation (MAHD) and conventional hydrodistillation (HD). As a result, the best conditions for the maximum essential oil production were determined for the MAHD method at 335 W microwave power for 30 min at water to raw material ratio of 8:3. The obtained essential oils were enriched in β-myrcene in the amount of 74.13%–89.32% (wt%). Moreover, the first application for determination of the above-mentioned volatile compounds by supercritical fluid chromatography (SFC) with photo-diode array detection (PDA) is presented, which in comparison with gas chromatography coupled with mass spectrometry (GC-MS/MS) resulted in similar values for β-myrcene and α-humulene in obtained samples within less than 1 min.

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Brazilian Grown Cascade Hop (Humulus lupulus L.): LC-ESI-MS-MS and GC-MS Analysis of Chemical Composition and Antioxidant Activity of Extracts and Essential Oils

Journal of the American Society of Brewing Chemists ◽

10.1080/03610470.2020.1795586 ◽

2020 ◽

pp. 1-11

Author(s):

Aline da Rosa Almeida ◽

Matheus Vinicius de Oliveira Brisola Maciel ◽

Bianca Cardoso Gasparini Gandolpho ◽

Michelle Heck Machado ◽

Gerson Lopes Teixeira ◽

...

Keyword(s):

Antioxidant Activity ◽

Chemical Composition ◽

Essential Oils ◽

Humulus Lupulus ◽

Esi Ms ◽

Ms Analysis ◽

Humulus Lupulus L

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Microwave-Assisted Hydrodistillation of Clove (Syzgium aromaticum) Stem Oil: Optimization and Chemical Constituents Analysis

Indonesian Journal of Chemistry ◽

10.22146/ijc.64521 ◽

2021 ◽

Vol 21 (6) ◽

pp. 1358

Author(s):

Haqqyana Haqqyana ◽

Ali Altway ◽

Mahfud Mahfud

Keyword(s):

Essential Oils ◽

Chemical Constituents ◽

Statistical Significance ◽

Polynomial Equation ◽

Extraction Yield ◽

High Yield ◽

Solvent Ratio ◽

Operational Parameters ◽

Microwave Assisted ◽

The Difference

One of the extensively prosperous potential aromatic plants is the clove (Syzgium aromaticum). This is owing to all parts of this plant (bud, stem, and leaves) contain a decent amount of essential oils. The current study focuses on the use of microwave-assisted hydrodistillation (MHD) in extracting clove stem essential oils. This study aims to obtain the best possible combination of operating parameters for a high yield of clove stem oil using response surface methodology. The current study adopted a face-centered central composite design to optimize the MHD operational parameters, including the feed-to-solvent ratio, microwave power, and extraction time. The observed data from the experiments were fitted to a reduced quadratic polynomial equation. The three operational parameters were shown to significantly affect the extraction yield of the clove stem oil (p < 0.05), yet the statistical significance for the interaction between each parameter was considerably weak. Furthermore, the adjusted R2 value measured comparably to the corresponding R2 value with the difference below 0.2, implying a high correlation between experimental and model-predicted data. Thus, this result demonstrates the suitability of the model used in the experiment.

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Evaluation of original historical clones of hops (Humulus lupulus L.)

KVASNY PRUMYSL ◽

10.18832/kp2019.66.382 ◽

2020 ◽

Vol 66 (6) ◽

pp. 382-391

Author(s):

Vladimír Nesvadba ◽

Jitka Charvátová ◽

Alena Henychová ◽

Josef Patzak

Keyword(s):

Essential Oils ◽

Genetic Difference ◽

High Ratio ◽

Climatic Conditions ◽

Humulus Lupulus ◽

Technological Parameters ◽

Humulus Lupulus L

The aim of this study was to compare yield and technological parameters of Czech historical hop clones, which were grown in our current climatic conditions. The highest yields from the selected original hop clones were found in “Úštěcký smetaňák” (1.93 t/ha), “Dubský zeleňák” (1.80 t/ha) and “Hřebčí chmel” (1.51 t/ha), which is probably caused by a genetic difference from Saazer hop. On the contrary, a low yield of hops was recorded in “Mastýřovický” (0.50 t/ha). In terms of brewing parameters, the highest contents of valuable alpha acids were detected in Osvald’s clones no. 147 a/I (3.88% w/w), no. 86 (3.71% w/w) together with no. 114 (3.45% w/w), while the lowest level (1.05% w/w) was found in “Hřebčí chmel” and “Úštěcký smetaňák”. The highest contents of essential oils were measured in Osvald’s clone no. 147 a/I (0.77% w/w), “Žatecká populace” (0.68% w/w) and Osvald’s clone no. 126 (0.65% w/w). Vice versa, the clones “Mastýřovický” (0.35% w/w), “Hřebčí chmel” (0.35% w/w) and “Tršický” (0.31% w/w.) exhibited the lowest contents. The evaluated hops displayed a relatively balanced composition of essential oils with the exception of “Dubský zeleňák”, which has an extremely low ratio of farnesene (4.35% rel.), but also a high ratio of selinene (8.95% rel.). Osvald’s clone no. 124b and 126 is genetically identical with the variety of Fuggle. The results show that clones “Hřebčí chmel”, “Úštěcký smetaňák” and “Dubský zeleňák” are different from other clones.

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