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. 2024 Sep 24;13(19):2675. doi: 10.3390/plants13192675

Hops across Continents: Exploring How Terroir Transforms the Aromatic Profiles of Five Hop (Humulus lupulus) Varieties Grown in Their Countries of Origin and in Brazil

Marcos Edgar Herkenhoff 1,2,*, Oliver Brödel 3, Marcus Frohme 3
Editors: Mohsin Kazi, Raees Khan
PMCID: PMC11478771  PMID: 39409545

Abstract

Humulus lupulus, or hops, is a vital ingredient in brewing, contributing bitterness, flavor, and aroma. The female plants produce strobiles rich in essential oils and acids, along with bioactive compounds like polyphenols, humulene, and myrcene, which offer health benefits. This study examined the aromatic profiles of five hop varieties grown in Brazil versus their countries of origin. Fifty grams of pelletized hops from each strain were collected and analyzed using HS-SPME/GC-MS to identify volatile compounds, followed by statistical analysis with PLS-DA and ANOVA. The study identified 330 volatile compounds and found significant aromatic differences among hops from different regions. For instance, H. Mittelfrüher grown in Brazil has a fruity and herbaceous profile, while the German-grown variety is more herbal and spicy. Similar variations were noted in the Magnum, Nugget, Saaz, and Sorachi Ace varieties. The findings underscore the impact of terroir on hop aromatic profiles, with Brazilian-grown hops displaying distinct profiles compared to their counterparts from their countries of origin, including variations in aromatic notes and α-acid content.

Keywords: Humulus lupulus, aromatic profile, terroir impact, volatile compounds, HS-SPME/GC-MS

1. Introduction

Humulus lupulus, commonly known as hops, is a species of flowering plant in the Cannabaceae family. It is native to Europe, Asia, and North America and is primarily known for its use in brewing beer [1]. The plant is a vigorous, climbing vine with rough stems and serrated leaves arranged oppositely along the stem. Hops are dioecious, meaning there are separate male and female plants. The female plants produce cone-like structures called strobiles, which are used in brewing to impart bitterness, flavor, and aroma to beer. These cones contain lupulin glands, which contain the essential oils and acids responsible for the characteristic bitterness and aroma of hops [2].

Apart from the most common compounds found in hop cones belonging to bitter acids (α- and β-acids) [3], there are at least several other bioactive compounds (essential oils and polyphenols) that make hop cones a feedstock with a broad range of microbiological properties [2,3,4]. Among various properties, hop cones contain compounds, such as prenylated flavonoids, which have been shown to possess sedative properties [5]. Certain compounds found in hops, such as phytoestrogens, have been investigated for their potential in hormone regulation. These compounds may have implications for conditions such as menopausal symptoms [6].

Hops offer health benefits due to their antioxidants, like polyphenols, which may reduce oxidative stress and chronic disease risk [7]. Compounds such as humulene and myrcene in hops are believed to have relaxing effects [8,9]. In addition, hundreds of aroma compounds are found in hop essential oils [10], though these oils constitute only about 0.5% to 3.0% of the hops’ dry weight [3]. The complex composition of hop essential oil makes characterizing its aroma a challenging task.

Despite the importance of characterizing aroma-related compounds in hops, the extraction methodologies commonly employed are often not very effective. Extraction techniques include steam distillation (SD), simultaneous distillation extraction (SDE), direct solvent extraction (DSE), and solvent-assisted flavor evaporation (SAFE). While SD and SDE are conventional methods, they can decompose volatile compounds due to high temperatures [11]. DSE extracts both volatiles and non-volatiles but is often used in combination with SAFE for thorough isolation. Although DSE-SAFE is an effective method, its high equipment costs and complexity limit accessibility. Headspace solid-phase microextraction (HS-SPME) is preferred for its solvent-free extraction and minimal sample volume requirements [11].

Regarding volatile and aromatic compounds, Su and Yin [11] conducted a study aimed at analyzing five fresh samples of Cascade and Chinook hops from different locations in Virginia using headspace solid-phase microextraction gas chromatography mass spectrometry olfactometry (HS-SPME-GC-MS-O). They identified 33 aromatic compounds, including esters, monoterpenes, sesquiterpenes, terpenoids, an aldehyde, and an alcohol. Furthermore, the authors demonstrated how the cultivation location can significantly influence the aroma profiles of Cascade and Chinook hops [11]. This study demonstrated the effect of location on the production of volatile compounds in these hop varieties. Additionally, in Brazil, there has been an expansion in hop production involving foreign varieties.

Based on these principles and considering that volatile compounds are extremely important for determining the hop profile, as well as their application in the food, cosmetics, or pharmaceutical industries, this study aimed to evaluate the aromatic profile of the hop varieties Hallertauer Mittelfrüher, Magnum, Nugget, Saaz, and Sorachi Ace. Except for Sorachi Ace, the study compared samples from their countries of origin with samples of the same varieties grown in Brazil using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS).

2. Material and Methods

2.1. Samples

For this study, 50 g samples of pelletized hops from five distinct strains were collected, with samples planted in their countries of origin, except for Sorachi Ace, which was compared with samples of the same strains planted in Brazil. Samples of Magnum and Hallertauer Mittelfrüher hops were obtained from Germany, Nugget and Sorachi Ace from the United States, and Saaz from the Czech Republic, all sourced from Barth Haas (Nuremberg, Germany). The Brazilian hops, Hallertauer Mittelfrüher, Nugget, and Saaz, were sourced from Dalcin (Taguaí, SP, Brazil), and the Magnum and Sorachi Ace hops from Brava Terra (Fortuna, SP, Brazil) (Table 1).

Table 1.

Characteristics of the five hop (Humulus lupulus) varieties used in the present study.

Hop Strain Typical Use Company Origin Harvest Alpha Acid (%) *
Hallertauer Mittelfrüher Aroma Dalcin Brazil 2021 6.88
Barth Haas Germany 2020 4.50
Magnum Bitter Brava Terra Brazil 2021 12.81
Barth Haas Germany 2020 14.70
Nugget Bitter Dalcin Brazil 2021 9.66
Barth Haas United States 2018 9.50
Saaz Aroma Dalcin Brazil 2021 5.67
Barth Haas Czech Republic 2020 3.50
Sorcachi Ace Aroma/Bitter Brava Terra Brazil 2021 8.70
Barth Haas United States 2020 10.80

* The measurement of alpha acids in hops was conducted using high-performance liquid chromatography (HPLC). This method is regulated by organizations such as the American Society of Brewing Chemists (ASBC 1) and the European Brewery Convention (EBC 2). 1 ASBC methods of analysis—Hops-14 (HPLC method for alpha and beta acids in hops and hop products), American Society of Brewing Chemists, 2014. 2 Analytica-EBC, Method 7.4 (alpha acids in hops and hop products by HPLC), European Brewery Convention, 2010.

The samples were manually ground into a fine powder using a mortar and pestle for subsequent analysis. Ground hop samples (40 ± 0.5 mg) were placed in a 20 mL glass vial with an automatic sampler. The vials were sealed with PTFE/silicone septa and aluminum caps (Macherey-Nagel, Bethlehem, PA, USA).

2.2. Instrumentation

The volatile compound profiles were analyzed using headspace solid-phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC–MS). This analysis employed the GCMSQP2020 NX system, incorporating the Nexis GC-2030 gas chromatograph, a quadrupole mass spectrometer, and the AOC-6000 Plus autosampler, all supplied by Shimadzu (Nakagyo-ku, Kyoto, Japan). For HS-SPME extraction, a DVB/CAR/PDMS (divinylbenzene–carboxen–polydimethylsiloxane) Smart Fiber (80 μm) from Shimadzu was utilized.

Prior to analysis, the fiber was preconditioned at 240 °C, and two blank injections were performed according to the manufacturer’s guidelines. Samples were equilibrated for 10 min at 50 °C in the autosampler’s heat block. The extraction process involved exposing the SPME fiber to the sample headspace for 50 min. The fiber was then inserted into the GC injector port for 3 min at 230 °C in splitless mode (using an SPME glass liner with a 0.75 mm ID), enabling thermal desorption of the volatile compounds. GC separation was performed with a constant helium flow (1 mL/min) on a PEG capillary column (HP-INNOWAX, 30 m, 0.25 mm ID, 0.15 μm) from Shimadzu. The oven temperature was programmed to increase from 40 °C to 150 °C at a rate of 5 °C per minute, followed by a ramp to 225 °C at 20 °C per minute, with initial and final holding times of 5 min and 20 min, respectively, as described by Su and Yin [11].

Mass spectrometry detection was carried out using electron-impact (EI) ionization at 70 eV in full-scan mode within the 40–350 amu range. The transfer line and ion source were maintained at 250 °C. Data acquisition was conducted in total ion current (TIC) mode.

2.3. Volatile Compounds Identification and Database Software Analysis

The detection of volatile compounds was conducted by comparing each peak’s molecular fragmentation pattern against the mass spectra available in the 2020 NIST MS database library (National Institute of Standards and Technology, Gaithersburg, MD, USA). A compound was considered identified if it displayed a similarity index (SI) exceeding 85. In cases of ambiguous identifications, retention indices were calculated using a series of n-alkanes (C8–C23) as references for confirmation.

Chromatographic profiles from the samples were analyzed using chemometric classification methods. These methods aim to leverage experimental data to predict the qualitative properties of the samples, referred to as categories or classes. Specifically, the goal was to determine the aroma characteristics of the hop samples. Given the multivariate nature of the experimental data (i.e., the chromatographic profiles), this study focused on employing partial least squares discriminant analysis (PLS-DA) to construct a classification model.

Each identified compound was queried using its CAS Registry Number in the PubChem database (https://pubchem.ncbi.nlm.nih.gov/) (accessed on 1 August 2024). Furthermore, the flavor and aroma profiles of these compounds were examined using the Perflavory database (https://perflavory.com/search.php) (accessed on 1 August 2024).

2.4. Statistical Analysis

For statistical analysis, the results were presented as mean ± standard deviation (SD). To quantify the volatile compounds common in at least two of the analyzed styles, the identified peak areas were automatically converted into Area% using LabSolutions GCMSolutions software version 1 (Shimadzu, Kyoto, Japan). This quantification approach was adopted because, as per the manufacturer, employing a specific standard for quantification ensures consistent concentration levels across all samples. Student’s t-test was utilized for comparing two samples, given that normal distribution was confirmed. For comparing three or more samples, an analysis of variance (ANOVA) was performed, followed by the Tukey test. Differences were considered statistically significant when p ≤ 0.05 (5% significance level).

3. Results and Discussion

3.1. Classification by PLS-DA

To investigate data trends and sample correlations, a multivariate analysis was utilized. A classification model was specifically created to highlight the differences related to the production method. Chromatographic profiles, illustrated as GC-MS total ion currents (TIC), were processed using PLS-DA to distinguish between the hop varieties planted in Brazil and those in their countries of origin (Figure 1).

Figure 1.

Figure 1

Figure 1

Chemical interpretation of the PLS-DA model discriminating between hops planted in their countries of origin (red) and the same varieties planted in Brazil (blue). Samples are based on VIP scores and regression coefficients. The selected hop varieties were (A) Hallertauer Mittelfrüh, (B) Magnum, (C) Nugget, (D) Saaz, and (E) Sorachi Ace. The chromatogram regions significantly contribute to the PLS-DA model.

To evaluate chemical differences between the beer groups analyzed, variable importance in projection (VIP) scores were calculated from the PLS-DA model. VIP scores measure the contribution of individual variables to the model, with higher scores indicating greater importance. Normalized VIP scores greater than one are generally considered significant. By combining PLS regression coefficients with VIP scores, we can identify key compounds for distinguishing among sample types and gain insights into the direction of observed variations.

3.2. Aromatic Hop Profile

A total of 330 different volatile compounds were identified using HS-SPME/GC-MS across all hop samples (Table S1). Although several of these compounds exhibit distinct aroma and odor profiles, the suppliers of these hops, as well as Beer Maverick (https://beermaverick.com/) (accessed on 1 August 2024), have already reported differentiated profiles (Figure 2).

Figure 2.

Figure 2

Aromatic profiles according to the hop (Humulus lupulus) strain producers for the varieties used in this study grown in their countries of origin (DE: Germany; USA: United States; and CZ: Czech Republic) and grown in Brazil (BR).

H. Mittelfrüher grown in Germany has a more spicy and herbal profile compared to the one grown in Brazil, which has a greener profile (Figure 2). Magnum grown in Germany has a spicier profile, whereas the one grown in Brazil features floral, berry, tropical fruit, citrus, and herbal notes. Nugget grown in the United States has a more herbal and woody profile, while the same variety grown in Brazil presents citrus, floral, and berry characteristics. Saaz grown in the Czech Republic has a slightly more woody and floral profile, while the same variety in Brazil exhibits more herbal, spicy, and citrus notes. Finally, Sorachi Ace grown in the United States shows almost the same pattern as the same variety in Brazil, except that the Brazilian variety is slightly more woody, tropical, citrus, herbal, and floral but maintains a very similar sensory pattern. It is interesting to note that the same variety planted in its country of origin, in this case, Japan, and according to Beer Maverick (https://beermaverick.com/), also has the same profile, except for the absence of a woody profile. This may indicate a variety with little terroir effect.

A study analyzed 33 active aromatic compounds in hop samples from the Cascade and Chinook varieties harvested from different locations in Virginia. Using chromatography and olfactometry techniques, the presence of esters, monoterpenes, sesquiterpenes, and terpenoids, among other compounds, was identified, exhibiting various aromatic characteristics, such as fruity, herbal, woody, and citrus notes [11].

3.3. Hallertauer Mittelfrüher

H. Mittelfrüher (HM) is a hop variety that has shown a higher α-acid content when planted in Brazil, according to its suppliers (Table 1). When grown in Taguaí, São Paulo, it presents a content of 6.88%, compared to 4.50% in Germany. A more recent study with the same hop variety from the western region of Paraná, Brazil, indicated α-acid levels of 5.9%, β-acid levels of 1.80%, and an essential oil content of 1.1 mL/100 g [12].

In terms of compound quantities, calculated by % area, 14 compounds were more expressed in the German HM, while 23 were more expressed in the Brazilian HM (Table 2). Among the 14 compounds more expressed in the German variety, 11 are related to aroma or odor. In the Brazilian HM, 13 of the 23 more-expressed compounds are associated with aroma or odor. Regarding unique compounds, 64 were identified in the German HM compared to Brazilian HM, with 28 of these related to aroma (Table 3). In the Brazilian HM, 45 unique compounds were found compared to the German HM, with 22 being related to aroma.

Table 2.

Compounds that showed their variation in expression (p ≤ 0.05) comparing the hop (Humulus lupulus) varieties planted in their country of origin with those planted in Brazil, in the hop variety of Hallertauer Mittelfruher, Magnum, Nugget, Saaz, and Sorachi Ace, planted in Germany (DE), United States (USA), Czech Republic (CZ), and Brazil (BR). Orange indicates higher expression, and blue is lower.

Compound CAS # Retention Index Odor Flavor H. Mittelfrüher Magnum Nugget Saaz Sorachi Ace
Type Strength Type DE BR DE BR USA BR CZ BR USA BR
alpha-Pinene 80-56-8 948 Herbal High Woody
2-Methyl-1-butanol 137-32-6 697 Ethereal Medium Ethereal
2-Methyl-1-Butanol 1565-80-6 697
beta-Pinene 127-91-3 943 Herbal High Pine
Myrcene 123-35-3 958 Spicy High Woody
alpha-Phellandrene 99-83-2 969 Terpenic Medium Terpenic
alpha-Terpinene 99-86-5 998 Woody Medium Terpenic
dextro-Limonene 5989-27-5 1018 Citrus Medium Citrus
alpha-Terpineol 555-10-2 964 Minty Medium
Pentan-2-yl propanoate 54004-43-2 920
Methyl (E)-4-methylpent-2-enoate 50652-78-3 828
2-Pentene, 1-ethoxy-4-methyl-, (Z)- 51149-75-8 836
2-Methylpropyl 3-methylbutanoate 589-59-3 955 Fruity Medium Green
Isoamyl isobutyrate 2050-1-3 955
2-Methylbutyl 2-methylpropanoate 2445-69-4 955 Fruity
Ortho-cymene 527-84-4 1042
1-Methyl-4-propan-2-ylidenecyclohexene 586-62-9 1052 Herbal Medium Woody
Methyl heptanoate 106-73-0 984 Fruity Fruity
2-Octanone 111-13-7 952 Earthy Medium Dairy
3-Methylbut-2-enyl 2-methylpropanoate 76649-23-5 1004 Fruity
Methyl Methylenecyclohexanoate 73805-48-8 951
1-Octen-3-ol 3391-86-4 969 Earthy High Mushroom
3-Methylbutyl 2-methylbutanoate 27625-35-0 1054 Fruity Fruity
2-Methylbutyl 2-methylbutyrate 2445-78-5 1054 Fruity Fruity
Isoamyl isovalerate 2445-77-4 1054 Fruity Fruity
Methyl 6-methylheptanoate 2519-37-1 1019
Perillene 539-52-6 1125 Woody Medium
Hexahydro-1,1-dimethyl-4-methylene-4H-cyclopenta[c]furan 344294-72-0 1052
Hexyl 2-methylpropanoate 2349-7-7 1054
Methyl octanoate 111-11-5 1083 Waxy Green
2-Methylpropyl hexanoate 105-79-3 1118 Fruity Medium Fruity
Benzaldehyde 100-52-7 982 Fruity High Fruity
2-Nonanone 821-55-6 1052 Fruity Medium Cheesy
4-Hydroxy-3-hexanone 4984-85-4 916
Octanol 111-87-5 1059 Waxy Medium Waxy
Linalool 78-70-6 1082 Floral Medium Citrus
Methyl 6-methyloctanoate 5129-62-4 1118
Heptyl propanoate 2216-81-1 1183 Floral Fruity
Heptyl isobutyrate 2349-13-5 1218 Fruity Berry
Methyl nonanoate 1731-84-6 1183 Fruity Winey
Hexanoic acid 142-62-1 974 Fatty Medium Cheesy
2-Methylbutyl hexanoate 2601-13-0 1218 Ethereal
alpha-Ylangene 14912-44-8 1221
alpha-Copaene 3856-25-5 1221 Woody
2-Decanone 693-54-9 1151 Floral Medium Fermented
Decyl trifluoroacetate 333-88-0 1216
7-Decen-2-one 35194-33-3 1159
Methylidenenonene 55050-40-3 1156 Aldehydic Medium
5-methylhexanoic acid 628-46-6 1009 Fatty Medium
2-(2,4-difluorophenyl)-1-[4-[6-(4-methylpiperazin-1-yl)pyridazin-3-yl]piperazin-1-yl]ethanone 1191-2-2 868
beta-Copaene 18252-44-3 1216
2-Undecanone 112-12-9 1251 Fruity Medium Waxy
beta-Caryophyllene 87-44-5 1494 Spicy Medium Spicy
(Z)-Undec-6-en-2-one 107853-70-3 1259
Trans-geranic acid methyl ester 1189-9-9 1054
(E)-beta-farnesene 18794-84-8 1440 Woody
alpha-Humulene 6753-98-6 1579 Woody
(Z,E)-alpha-Farnesene 26560-14-5 1458
(-)-alpha-Muurolene 10208-80-7 1440 Woody
alpha-Selinene 473-13-2 1474 Amber
(3R,4aS,8aR)-8a-methyl-5-methylidene-3-prop-1-en-2-yl-1,2,3,4,4a,6,7,8-octahydronaphthalene 17066-67-0 1469 Herbal
alpha-Farnesene 502-61-4 1458 Woody Green
(-)-alpha-Gurjunene 489-40-7 1419 Woody
(-)-gamma-Cadinene 39029-41-9 1435 Woody Medium
(+)-delta-Cadinene 483-76-1 1469 Herbal
Zonarene 41929-5-9 1440
Naphthalene, 1,2,3,4,4a,7-hexahydro-1,6-dimethyl-4-(1-methylethyl)- 16728-99-7 1440
alpha-Cedrene 24406-5-1 1440
Perilla alcohol 18457-55-1 1261
2-Tridecanone 593-8-8 1164
Geranyl Propionate 105-90-8 1451 Floral Medium Waxy
Calamenene 483-77-2 1537 Herbal Spicy Medium
Geranyl Butyrate 106-29-6 1550 Fruity Medium Fruity
(Z,Z)-1,8,11-heptadecatriene 56134-3-3 1164
(Z)-3-decen-1-yl acetate 81634-99-3 1389
Methyl ester 3,6-dodecadienoic acid 16106-1-7 1164
Linalool oxide 5989-33-3 1164 Earthy Medium
beta-Calacorene 50277-34-4 1542
Heneicosapentaenoic acid methyl ester 65919-53-1 2415
Linolenyl Alcohol 506-44-5 2077
2-n-Butyl-2-cyclopentenone 5561_5-7 1280
1-Epi-cubenol 19912-67-5 1580
beta-Caryophyllene oxide 1139-30-6 1507 Woody Medium Woody
Isoascaridole 19888-33-6 1592 Herbal
Neointermedeol 5945-72-2 1613
Humulene oxide II 19888-34-7 1592
Methyl (8Z,11Z,14Z,17Z)-icosa-8,11,14,17-tetraenoate 132712-70-0 2308
Cadalene 483-78-3 1706
Caryophylla-4(12),8(13)-dien-5.alpha.-ol 19431-79-9 1677
Methyl (Z)-5,11,14,17-eicosatetraenoate 59149-1-8 1280

Table 3.

Unique volatile for each hop (Humulus lupulus) variety compared between samples planted and their country of origin with planted in Brazil. The varieties included Hallertauer Mittelfruher, Magnum, Nugget, Saaz, and Sorachi Ace, planted in Germany (DE), United States (USA), Czech Republic (CZ), and Brazil (BR). The green color indicates the presence of a specific compound in the hop samples studied.

Compound CAS # Retention Index Odor Flavor H. Mittelfrüher Magnum Nugget Saaz Sorachi Ace
Type Strength Type DE BR DE BR USA BR CZ BR USA BR
2-Methyl-1-butanol 137-32-6 697 Ethereal Medium Ethereal
Methyl isobutyrate 547-63-7 621 Fruity Ethereal
Dimethyl disulfide 624-92-0 722 Sulfurous Sulfurous
alpha-Phellandrene 99-83-2 969 Terpenic Medium Terpenic
Isovaleric acid 503-74-2 811 Cheesy High Cheesy
Heptyl isobutyrate 2349-13-5 1218 Fruity Berry
Linalool oxide 5989-33-3 1164 Earthy Medium
Acetone 67-64-1 455 Solvent High
Geranyl isovalerate 109-20-6 1586 Fruity Medium Green
alpha-Myrcene 3338-55-4 976 Floral Medium Green
Hexyl acetate 142-92-7 984 Fruity Medium Fruity
Pentyl isobutyrate 2445-72-9 1019 Fruity
2-Nonanol 628-99-9 1078 Waxy Waxy
(-)-gamma-Elemene 29873-99-2 1431 Green Medium
(-)-gamma-Cadinene 39029-41-9 1435 Woody Medium
beta-Cadinene 523-47-7 1440 Woody Medium
Neryl butyrate 999-40-6 1550 Green Green
Calamenene 483-77-2 1537 Herbal Spicy Medium
Isoascaridole 19888-33-6 1592 Herbal
Cedrol 19435-97-3 1580 Herbal Medium
alpha-Muurolene 17699-14-8 1344 Herbal
beta-Bisabolene 28973-97-9 1440 Green
Methyl Isovalerate 23747-45-7 940 Cheesy Fermented
1-Hexanol 111-27-3 860 Herbal Green
Beta-Myrcene 502-99-8 958 Fruity Medium
Methyl Heptenone 110-93-0 938 Citrus Medium Green
Isoamyl Isovalerate 2445-77-4 1054 Fruity Fruity
Methyl Nonenoate 13481-87-3 1191 Fruity Medium Fruity
Delta-3-Carene 13474-59-4 1430 Woody
Viridiflorol 20307-83-9 1446 Herbal Medium
Geranyl Propionate 105-90-8 1451 Floral Medium Waxy
Geranyl Butyrate 106-29-6 1550 Fruity Medium Fruity
Beta-Farnesene 21391-99-1 1547 Woody Medium
Muscone 37609-25-9 2072 Musk Medium
Alpha-Phellandrene 3779-61-1 976 Sweet Herbal Medium
Octyl Isobutyrate 109-15-9 1317 Waxy Medium Creamy
Methyl 2-Methylbutanoate 868-57-5 721 Fruity Fruity
Methyl Isovalerate 556-24-1 721 Fruity Medium Fruity
beta-Pinene 127-91-3 943 Herbal High Pine
Methyl Caproate 106-70-7 884 Fruity Medium Fruity
Ethyl Propanoate 105-37-3 686 Fruity High Fruity
2-Methyl-1-Butanol 1565-80-6 697
Isobutyl Isobutyrate 97-85-8 856 Fruity Fruity
Ethyl Isohexanoate 25415-67-2 920 Fruity
alpha-Terpineol 555-10-2 964 Minty Medium
Dodecane 112-40-3 1200 Alkane
Methyl Octanoate 15870-7-2 884
Methyl 2-Methylheptanoate 51209-78-0 1019
6-Methyl-5-Hepten-2-one 49852-35-9 896
2-Octanone 111-13-7 952 Earthy Medium Dairy
Methyl Methylenecyclohexanoate 73805-48-8 951
Beta-Pinene 514-95-4 992
Methyl 7-Methyloctanoate 2177-86-8 1118
Octyl Acetate 112-14-1 1183 Floral Medium Waxy
Pentyl Cyclohexadiene 56318-84-4 1143
Hexanoic Acid 142-62-1 974 Fatty Medium Cheesy
7-Decen-2-one 35194-33-3 1159
Methylidenenonene 55050-40-3 1156 Aldehydic Medium
Octyl Propanoate 142-60-9 1282 Fruity Estery
Pentadecene 13360-61-7 1502
beta-Cedrene 30021-74-0 1435 Woody
alpha-Cedrene 24406-5-1 992
Geranyl Isovalerate 51117-19-2 1586
Linolenyl alcohol 506-44-5 2077
Methyl 4-Methylpentanoate 2412-80-8 820 Fruity Fruity
Carene 3387-41-5 897 Woody Woody
Ethyl Hexanoate 123-66-0 984 Fruity High Fruity
Pentyl Propanoate 624-54-4 984 Fruity Fruity
4-Pentenyl Butyrate 30563-31-6 1073
5-Methylheptan-2-ol 54630-50-1 915
Ethyl 5-Methylhexanoate 10236-10-9 1019
Methyl (E)-Hept-2-enoate 22104-69-4 992
(Z)-Hex-2-enyl Acetate 56922-75-9 992
Ethyl Octanoate 106-32-1 1183 Waxy Medium Waxy
beta-Bisabolene 495-61-4 1500 Balsamic
1-Methyloctyl acetate 14936-66-4 1218
2,3,5-Trithiahexane 42474-44-2 1072 Sulfurous
Alloisolongifolene 87064-18-4 1390
1-Tetradecene 1120-36-1 1403
Ethyl trans-4-decenoate 76649-16-6 1389 Green Medium Fatty
Neryl isobutyrate 2345-24-6 1486 Fruity Medium Fruity
Methyl petroselinate 2777-58-4 2085
Germacrene B 15423-57-1 1603 Woody
1-Tridecene 2437-56-1 1304
Agarospirol 1460-73-7 1598
Muurola-4,10(14)-dien-1 beta-ol 257293-90-6 1586
Ethyl octanoate 106-32-1 1183 Waxy Medium Waxy
Trans-propionate 2-methyl-cyclohexanol 15287-79-3 1208
2-Methylcyclohexyl butyrate 15287-80-6 1307
3-Methylpentanoic acid 105-43-1 910 Animal Medium Sour
cis-3-Hexenyl butyrate 16491-36-4 1191 Green Medium Green
(2S,4S)-2,4-Dimethylhexanoic acid methyl ester 14251-45-7 955
Ethyl heptanoate 106-30-9 1083 Fruity Medium Fruity
Hexyl propanoate 2445-76-3 1083 Fruity
Neo-alloocimene 7216-56-0 993
Methyl non-4-enoate 20731-19-5 1191
2-Methyl-6-methyleneocta-2,7-dien-4-ol 14434-41-4 1200
Eremophilene 10219-75-7 1474
Geranyl acetate 105-87-3 1352 Floral Medium Green
Gamma-maalinene 20071-49-2 1398
(-)-Aristolene 6831-16-9 1403
2-Tetradecanone 2345-27-9 1549
trans-Nerolidol 40716-66-3 1564 Floral Low Green
1-cyclododecyl-ethanone 28925-0-0 955
Linolenyl alcohol 506-44-5 2077
alpha-Cadinol 481-34-5 1580 Herbal Medium
2,2,4,6,6-pentamethylheptane 13475-82-6 981
Butyl nitrite 544-16-1 609
1-Pentanol 71-41-0 761 Fermented Fusel
2-methylbutyl propanoate 2438-20-2 920 Fruity
Benzaldehyde 100-52-7 982 Fruity High Fruity
6-methylheptanoic acid 929-10-2 1109
5-Nonenoic acid methyl ester 20731-20-8 1191
Heptanoic acid 111-14-8 1073 Cheesy Waxy
Neryl isobutyrate 2345-24-6 1486 Fruity Medium Fruity
Perillyl alcohol 536-59-4 1261 Green Medium Woody
Isopentyl 8-methylnon-6-enoate 1215128-16-7 1559
4,8,11,11-tetramethylbicyclo[7.2.0]undec-3-en-5-ol 913176-41-7 1677
(6Z,9Z,12Z,15Z)-Methyl octadeca-6,9,12,15-tetraenoate 73097-0-4 943
Bicyclo[3.1.1]hept-2-ene, 2,6-dimethyl-6-(4-methyl-3-pentenyl)- 17699-5-7 1474
Methyl 5-methyl-2-hexenoate 68797-67-1 928
4,6-Dimethyloctanoic acid 2553-96-0 1154
1,3-Nonadiene 56700-77-7 914
Camphene 79-92-5 943 Woody Medium Camphoreous
alpha-Terpinene 99-86-5 998 Woody Medium Terpenic
Borneol 464-45-9 1138 Balsamic Medium Camphoreous
10-Epizonarene 41702-63-0 1469
alpha-Farnesene 502-61-4 1458 Woody Green
(+)-delta-Cadinene 483-76-1 1469 Herbal
Naphthalene, 1,2,3,4,4a,7-hexahydro-1,6-dimethyl-4-(1-methylethyl)- 16728-99-7 1440
1-Octadecene 112-88-9 1801
(2Z,6E)-Farnesol 3790-71-4 1710
4-methyl-5-propylnonane 62185-55-1 1185
3-Methylbut-2-enyl 2-methylpropanoate 76649-23-5 1004 Fruity
2,6-dimethyl-1,3,5,7-octatetraene, E,E- 460-1-5 955
Heptyl propanoate 2216-81-1 1183 Floral Fruity
alpha-Guaiene 3691_12-1 1054 Woody
Methyl linolelaidate 2462-85-3 955
Methyl dodecanoate 111-82-0 1481 Waxy Medium Waxy
Methyl decanoate 110-42-9 1282 Fermented Fatty
2-methylpropyl propanoate 540-42-1 955 Fruity Fruity
Pentan-2-yl propanoate 54004-43-2 920
3-methylbutyl 3-methylbutanoate 659-70-1 1054 Fruity Medium Green
S-propyl hexanethioate 2432-78-2 1303
(Z)-Undec-6-en-2-one 107853-70-3 1259
(-)-alpha-Gurjunene 489-40-7 1419 Woody
.alpha.-Maaliene 489-28-1 1403
Methyl petroselinate 2777-58-4 2085
Perilla alcohol 18457-55-1 1261
Heneicosapentaenoic acid methyl ester 65919-53-1 2415
2,2-dimethyldecane 17302-37-3 1130
3-methylbut-2-enal 107-86-8 692 Fruity Fruity
3,5-dimethyl-1,6-heptadiene 68701-99-5 768
(Z)-9-methylundec-5-ene 74630-65-2 1158
Methyl (E)-4-methylpent-2-enoate 50652-78-3 828
(Z)-hex-3-en-1-ol 928-96-1 868 Green High Green
2-methylbutanoic acid 116-53-0 811 Acidic Medium Fruity
Methyl 2,4-dimethylnonanoate 54889-61-1 1253
2-methyl-6-methylene-2-octene 10054-9-8 1054
3,3-dimethylcyclohexan-1-one 2979-19-3 1025
Decyl trifluoroacetate 333-88-0 1216
2-Nonanone 821-55-6 1052 Fruity Medium Cheesy
Fenchol 1632-73-1 1138 Camphoreous Medium Camphoreous
11,14-Eicosadienoic acid, methyl ester 2463_02-7 1054
beta-Bisabolene 495-61-4 1500 Balsamic
(E)-alpha-bisabolene 25532-79-0 1518
3-(1,1-dimethylethyl)-2,5-furandione 18261-7-9 1054
1-methyl-3-propan-2-ylbenzene 535-77-3 1042
Methyl (Z)-octadec-9-enoate 112-62-9 2085 Mild fatty Low
trans-Furan linalool oxide 34995-77-2 1164 Floral Medium
3-methoxybutan-2-ol 53778-72-6 692
alpha-Pinene 80-56-8 948 Herbal High Woody
Butyl 2-methylpropanoate 97-87-0 920 Fruity Fruity
2-Methylpropyl 3-methylbutanoate 589-59-3 955 Fruity Medium Green
Isoamyl isobutyrate 2050-1-3 955
(Z)-3-hexen-1-yl acetate 3681-71-8 992 Green High Green
Methyl (2S,4R)-2,4-dimethylheptanoate 18450-78-7 1054
2-methylpent-4-en-1-ol 5673-98-3 786
[(Z)-hex-3-enyl] 2-methylbutanoate 53398-85-9 1226 Green Medium Green
Methyl 10-undecenoate 111-81-9 1371 Fatty Waxy
alpha-Selinene 473-13-2 1474 Amber
2-Isopropenyl-4a,8-dimethyl-1,2,3,4,4a,5,6,7-octahydronaphthalene 103827-22-1 1502
Geraniol 106-24-1 1228 Floral Medium Floral
Methyl ester 3,6-dodecadienoic acid 16106-1-7 1164
2-hexadecyloxirane 7390-81-0 1054
Neryl propionate 105-91-9 1451 Fruity Medium Green
Aplotaxene 10482-53-8 1725 Costus
2-Nonadecanone 629-66-3 2046
Methyl 7Z-hexadecenoate 56875-67-3 1886
Methyl (8Z,11Z,14Z,17Z)-icosa-8,11,14,17-tetraenoate 132712-70-0 2308
Prenol 556-82-1 746 Fruity Fruity
Isobutyl 2-methylbutyrate 2445-67-2 955 Fruity Fruity
Ortho-cymene 527-84-4 1042
Methyl heptanoate 106-73-0 984 Fruity Fruity
2-Methylbutyl 2-methylbutyrate 2445-78-5 1054 Fruity Fruity
Heptyl ester acetic acid 112-6-1 1054
hexyl 2-methylpropanoate 2349-7-7 1054
Methyl octanoate 111-11-5 1083 Waxy Green
Mesityl oxide 141-79-7 739 Vegetable Potato
2-Heptanone 110-43-0 853 Cheesy High Cheesy
3-Methylbutyl propanoate 105-68-0 920 Fruity Medium Fruity
1-Dodecene 112-41-4 1204
1-Cyclohexyl-2-buten-1-ol 79605-62-2 1249
2-Methylpropyl hexanoate 105-79-3 1118 Fruity Medium Fruity
1,1-Cyclohexanedimethanol 2658-60-8 1339
2-Methyl-2-(4-methyl-3-pentenyl)-cyclopropanemethanol 98678-70-7 1280
2-Methyl-2-pentenoic acid 16957-70-3 1054 Fruity Medium
(1S,4S,4aS)-1-Isopropyl-4,7-dimethyl-1,2,3,4,4a,5-hexahydronaphthalene 267665-20-3 1440
Calarene 17334-55-3 1403
Cyclodecene 3618-12-0 1181
Alpha-dehydro-ar-himachalene 78204-62-3 1601
2-ethylidene-1,7,7-trimethylbicyclo[2.2.1]heptane 62413-60-9 1134
2-n-Butyl-2-cyclopentenone 5561_5-7 1054
beta-Caryophyllene oxide 1139-30-6 1507 Woody Medium Woody
(-)-Camphene 5794_04-7 1280
5-Methylhexan-3-one 623-56-3 789
2-Pentene, 1-ethoxy-4-methyl-, (Z)- 51149-75-8 836
(E)-hex-4-en-1-ol 928-92-7 868 Green Green
Di(imidazol-1-yl)methanone 530-62-1 1445
Ethyl 3-hexenoate 2396-83-0 992 Fruity Medium Fruity
2-methylbutyl butanoate 51115-64-1 1019 Fruity Fruity
1-Heptanol 111-70-6 960 Green Medium Solvent
Methyl nonanoate 1731-84-6 1183 Fruity Winey
2-Methylbutyl hexanoate 2601-13-0 1218 Ethereal
2-methyl-6-methylideneocta-1,7-dien-3-one 41702-60-7 1076
3,5-Dimethyl-1,6-heptadiene 68701-99-5 768
Nalpha,Nomega-Dicarbobenzoxy-L-arginine 53934-75-1 3543
2-(2,4-difluorophenyl)-1-[4-[6-(4-methylpiperazin-1-yl)pyridazin-3-yl]piperazin-1-yl]ethanone 1191-2-2 868

The German HM exhibits an aromatic profile rich in herbal, spicy, floral, fruity, and woody notes, whereas those from Brazil have an aromatic profile characterized by fruity, herbal, sweet, and woody notes. This aromatic profile aligns with the descriptions provided by the suppliers for both (Figure 2).

Among the compounds that are more highly expressed, we can highlight dextro-limonene (citrus), also known as D-limonene (Table 2). This compound acts against the cytoplasmic membranes of microorganisms, resulting in a loss of membrane integrity, altering its permeability, and leading to the loss of ions and proteins [13]. Benzaldehyde (fruity) is another significant compound, known as an inhibitor of quorum sensing for the opportunistic pathogen Pseudomonas aeruginosa [14]. Hexanoic acid (fatty) has been considered to have high sensory potential effects in Chinese ‘Marselan’ wines [15]. Additionally, 2-undecanone (fruity) is known for its antifungal activity against Colletotrichum gloesporioides [16]. Another property of this compound is its ability to alleviate asthma by reducing airway inflammation and remodeling. This beneficial effect is achieved through the inhibition of the NF-κB pathway [17].

Among the unique compounds in the Brazilian HM (Table 3), notable ones include 1-octen-3-ol (earthy), known for its antioxidant and antimicrobial properties [18]. This compound acts as a defense mechanism in seaweeds [19], potentially enhancing food preservation and contributing to overall health. It is also associated with aging flavors [18]. 1-Hexanol (herbal) is found abundantly in Pale Ale and Lambic beer styles [20] and holds significant potential for applications in the food and cosmetic industries [21]. Ethyl hexanoate (fruity), providing flavors typical of apples and pineapples, is a maturity marker in pequi fruits (Caryocar brasiliense) and is the most predominant compound in this fruit [22]. Methyl isobutyrate (fruity) can be detected in numerous foods and beverages and has been identified as a key volatile compound in Hunan Changde rice noodles fermented with Lactococcus [23]. Hexyl acetate is frequently used as a flavoring agent in a variety of food products, including candies, baked goods, and beverages. It is also an ingredient in perfumes, soaps, and other personal care products [24]. Moreover, the hexyl acetate identified in the grape pomace of the investigated grape varieties can be used similarly, serving as a flavoring agent in various food items and as a component in perfumes, soaps, and other personal care products [21]. This ester is also known for imparting a fragrance known as ‘Orange Beauty’ [25].

Among the most expressed compounds in the Brazilian HM, noteworthy ones include methyl heptanoate (fruity), which contributes to a fruity flavor and is found in various fruits. Methyl octanoate (waxy) adds a smooth, sweet flavor, common in some fruits and wines, and is one of the main flavoring agents in foods, possessing a vinous, fruity, and orange-like odor [26]. Octanol (waxy) has a pleasant aroma that contributes to the complexity of flavors in foods and is common in various beer styles [20].

3.4. Magnum

Unlike H. Mittelfrüher, Magnum is a hop variety that showed a lower α-acid content when planted in Brazil, according to its suppliers (Table 1). Regarding the quantity of compounds, calculated by % area, 26 compounds were more expressed in the German Magnum, while 20 were more expressed in the variety planted in Brazil (Table 2). Of the 26 more expressed in the German Magnum, 17 are related to aroma or odor. Of the 23 compounds more expressed in the Brazilian Magnum, 11 are related to aroma or odor. Regarding the compounds found in the German Magnum, 34 unique compounds were identified compared to the Brazilian Magnum (Table 3). Of this total, only 22 are related to aroma. In the Brazilian Magnum, seven unique compounds were found compared to the German Magnum. Among them, six are related to aroma.

The German Magnum hop profile is characterized by a blend of herbal, terpenic, woody, citrus, fruity, floral, and fatty notes. The key compounds contributing to this profile include alpha-pinene (herbal), alpha-phellandrene (terpenic), and geranyl butyrate (fruity), among others. The Brazilian Magnum exhibits a profile with fruity, floral, and woody notes. The key compounds responsible for this profile include 2-methylpropyl 3-methylbutanoate (fruity), methyl heptanoate (fruity), and (+)-delta-cadinene (herbal). The aromatic profiles of the German and Brazilian Magnum hop varieties are influenced by the specific compounds present in each group. The German Magnum is characterized by a complex mix of herbal, fruity, and woody notes, while the Brazilian Magnum is dominated by fruity, floral, and herbal aromas. These differences are due to the unique combination of compounds present in each group, influenced by factors such as terroir and cultivation practices.

Beer flavored with total Magnum hop oil has a unique sensory profile, featuring strong “crushed grass, sap”, “resinous”, “earthy”, and “musty” aromas. Magnum hop oil consists mainly of β-myrcene, β-caryophyllene, and α-humulene, making up to 80% of the oil. β-myrcene, the most abundant compound, can smell “spicy”, “resinous”, “metallic”, or “geranium-like” at different concentrations. The aromas of β-caryophyllene and α-humulene are less distinct but are described as “rubber-like”, “mouldy”, “woody”, and “spicy.” These aroma characteristics are also found in sesquiterpene-flavored beer, but at lower intensities, indicating that the total oil enhances them [27].

3.5. Nugget

In contrast to the hops mentioned in the previous sections, the α-acid content was the same in both the American and Brazilian Nugget (Table 1). Regarding the quantity of compounds, calculated by % area, 25 compounds were more expressed in the variety planted in the United States, while 19 were more expressed in the variety planted in Brazil (Table 2).

Among the 25 compounds more expressed in the American Nugget, 17 are related to aroma or odor (Table 2). Among the 19 compounds more expressed in the Brazilian Nugget, 7 are related to aroma or odor. Regarding the compounds found in the variety planted in the United States, 42 unique compounds were identified compared to the Brazilian Nugget (Table 3). Of this total, only 25 are related to aroma. In the Brazilian Nugget, 37 unique compounds were found compared to the American Nugget. Among them, 24 presented some relation to aroma.

Among the compounds most abundantly expressed in the American Nugget, notable ones include dextro-limonene (citrus), which is one of the primary compounds identified in the essential oil of Okoume (Aucoumea klaineana) [28], being studied for its bioactive constituents and antibacterial activities. Linalool (floral) is commonly found in large quantities in Indian Pale Ale beers but in smaller amounts in Pale Ale (IPA) [20]. 3-Methylbutyl 2-methylbutanoate (fruity) is reported to occur in foods such as apple brandy (Calvados), banana (Musa sapientum L.), cider (apple wine), date (Phoenix dactylifera L.), grape brandy, and passion fruit (Passiflora species), among others [29].

Among the compounds most abundantly expressed in the variety planted in Brazil, noteworthy is methyl octanoate (waxy), which, interestingly, was found in Annona crassiflora, known as marolo fruit from the cerrado biome. This species is one of the most consumed in the Brazilian Midwest, with this compound significantly contributing to its aroma [30].

Among the compounds found exclusively in the American Nugget, methyl isobutyrate (fruity) was previously mentioned as a volatile compound in Hunan Changde rice noodles fermented by Lactococcus [23] and is also an exclusive compound of Brazilian HM hops. Dimethyl disulfide (sulfurous) adds a sulfurous character, which is interesting for certain aromatic profiles. It is also one of the most abundant compounds in microwave-cooked radish (Raphanus sativus L.) oils [31]. Isovaleric acid (cheesy) imparts a cheesy character and was exclusively found in Bock beers [20], being perceived by many individuals as a very strong odor impression [32].

Among the compounds found exclusively in the Brazilian Nugget, hexyl acetate (fruity) is also an exclusive compound of Brazilian HM hops. It is a flavoring agent in a variety of food products and an ingredient in perfumes, soaps, and other personal care products [24]. Methyl dodecanoate (waxy) adds a waxy and sweet flavor and is one of the most variable compounds for distinguishing wine cultivars, contributing significantly to their sensory characteristics [33]. It was also isolated from the ethyl acetate extract of the culture filtrate of the probiotic Lactobacillus plantarum H24 [34]. 3-methylbutyl 3-methylbutanoate (fruity) contributes a fruity flavor, enhancing the complexity of the aroma. It is the most abundant compound in all of the flowering stages of Asian skunk cabbage (Symplocarpus renifolius, Araceae) [35] and is present in the odors of ripe bananas, guavas, and oranges. It is also found among the compounds that attract both sexes of the invasive African fruit fly Bactrocera invadens [36].

3.6. Saaz

The Saaz hop exhibits an α-acid content of 3.5 for the Czech, compared to 5.67 for the Brazilian (Table 1). Regarding the quantity of compounds, calculated by % area, 17 compounds were more expressed in the Czech Saaz, while 15 were more expressed in the Brazilian Saaz (Table 2).

Among the 17 compounds more expressed in the Czech Saaz, 10 are related to aroma or odor (Table 2). Of the 15 compounds more expressed in the Brazilian Saaz, 9 are related to aroma or odor. Regarding the compounds found in the variety planted in the Czech Saaz, 26 unique compounds were identified compared to the Brazilian Saaz (Table 3). Of this total, only 18 are related to aroma. In the Brazilian Saaz, 28 unique compounds were found compared to the Czech Saaz. Among them, 18 were related to aroma.

The differences in the aromatic profiles of the Czech and Brazilian Saaz are largely due to the variation in the expression of specific compounds, which are influenced by factors such as climate, soil, and cultivation practices. The presence of more spicy, earthy, woody, and floral compounds in the Czech Saaz suggests a more traditional and balanced aroma profile, while the Brazilian Saaz’s higher expressions of ethereal, herbal, fruity, and spicy compounds offer a unique and potentially more vibrant aroma.

These aromatic differences are crucial for brewers when selecting hops for specific beer styles, as the aroma profile of the hops can significantly influence the final product’s flavor and aroma. Understanding the specific compounds responsible for these aromas allows brewers to tailor their hop selections to achieve the desired sensory characteristics in their beers.

Regarding the compounds most expressed in Czech Saaz hops, linalool (floral) is commonly found in higher quantities in Indian Pale Ale beers [20]. 1-Octen-3-ol (earthy), known for its mushroom-like aroma, is a byproduct of the enzymatic degradation of linoleic acid and ethanol [37], and previous studies have shown that it functions as a defense compound in marine algae [19,38,39].

Among the compounds most expressed in Brazilian Saaz hops, benzaldehyde (fruity) primarily manifests as a sweet note. Regarding the unique compounds in Czech Saaz hops, isovaleric acid (cheesy) is noted for its sweaty–cheesy aroma and contributes to the sensory characteristics of Gouda cheese [40]. Hexanoic acid (fatty) plays a role in aromatic complexity and has been documented for its effects in Chinese wines [15].

For the unique compounds in Brazilian Saaz hops, hexyl acetate (fruity) is widely used in the food and cosmetic industries [24], is present in grape pomace [21], and is recognized for its distinct ‘Orange Beauty’ fragrance [25]. 3-Methylbutyl 3-methylbutanoate (fruity) contributes a fruity flavor and is the predominant compound in the flowering of Symplocarpus renifolius, Araceae [35].

3.7. Sorachi Ace

The Sorachi Ace (SA) hop exhibits an α-acid content of 10.8 in the American, while the Brazilian SA has an α-acid content of 8.7 (Table 1). Regarding the quantity of compounds, calculated by % area, 24 compounds were more expressed in the American SA, whereas 21 were more expressed in the Brazilian SA (Table 2).

Of the 24 compounds more expressed in the American SA, 13 are related to aroma or odor (Table 2). Of the 21 compounds more expressed in the Brazilian SA, 12 are related to aroma or odor. Regarding the compounds found in the American SA, 17 unique compounds were identified compared to the same Brazilian SA (Table 3). Of this total, only 13 are related to aroma.

In the Brazilian SA, 25 unique compounds were found compared to the American SA, among them, 17 have some relation to aroma.

The American SA tends to have a more diverse aromatic profile with herbal, citrus, and woody notes being dominant. The presence of compounds like 2,6,6-trimethylbicyclo[3.1.1]hept-2-ene and dextro-limonene significantly contribute to the herbal and citrus characteristics. The Brazilian SA exhibits a more fruity and spicy aromatic profile. Compounds such as myrcene and 3-methylbut-2-enyl 2-methylpropanoate are responsible for these attributes, providing a unique aroma compared to its American counterpart. The presence and concentration of specific volatile compounds influence the aromatic profile. Terpenes and esters are particularly important, as they are responsible for the distinct aromas of hops, affecting beer’s aroma and flavor. The unique environmental conditions and cultivation practices in the US and Brazil likely contribute to the differences in these aromatic compounds, resulting in variations in the hop profiles.

Sorachi Ace is a hop variety that imparts distinctive varietal aromas to the final beer, including woody, pine, citrus, dill, and lemongrass notes. The research concludes that the unique aroma of Sorachi Ace hops is due to the high levels of geranic acid, which acts synergistically with other hop-derived compounds to enhance the overall aroma. Sensory evaluations showed that late and dry hopping resulted in beers with significantly higher scores for flowery, fruity, tropical, and lemon characteristics compared to kettle-hopped beer [41].

Regarding the compounds most expressed in the American SA, we can highlight dextro-limonene (citrus), which is a compound exclusively found in the Gose style compared to other sours [20]. It is found in the essential oil of okoume [28] and also acts against the cytoplasmic membranes of microorganisms [13]. Benzaldehyde (fruity) provides fruity notes. Linalool (floral) is common in IPA. Regarding the compounds most expressed in the Brazilian SA, we can highlight 3-methylbut-2-enyl 2-methylpropanoate (fruity), which is one of the exclusive compounds found in the Farmhouse Ale beer style. 1-Octen-3-ol (earthy) is known for being an antioxidant and antimicrobial [18], acting as a defense mechanism in marine algae [19], and is associated with the aging of flavors [18]. This compound is produced from 10-linoleate hydroperoxide [42] and is the most abundant alcohol found in soybeans cultivated in North America [43]. 2-Nonanone (fruity) is a bioactive compound capable of promoting rice growth [44]. It was identified in the volatilome of Bacillus sp. BCT9, showing the ability to increase lettuce biomass by up to 48% after 10 days of exposure [45]. Regarding the compounds exclusive to the American SA, we can highlight isovaleric acid (cheesy), which, as discussed, is found exclusively in Bock beers [20] and has a strong impression on individuals [32]. Camphene (woody) is a component of rosemary (Rosmarinus officinalis) essential oil (Hendel et al., 2024). 1-Hexanol (herbal) is found in Lambic and Pale Ale beers [20] and has potential applications in the food industry (Abreu et al., 2023). Methyl heptenone (citrus) is a compound that signals freshness in algae (Cladostephus spongiosus) [46]. Hannaella and Neomicrosphaeropsis showed a significantly positive correlation with this compound produced during the fermentation of Petit Manseng sweet wine [47].

Regarding the compounds exclusive to the Brazilian SA, we can highlight hexyl acetate (fruity). As discussed, it is an important compound for food and perfume [24]. Octyl acetate (floral) is an exclusive compound found in Pilsen beers with hop extract [20], as well as in the Quadruppel beer style as an exclusive compound [20]. This compound is a useful marker for monitoring the fermentation process, as its post-fermentation concentration increases proportionally to the pre-fermentation concentration of the corresponding alcohol [48]. Large amounts of this compound have also been associated with potential antioxidant and anticancer effects in the leaves of the Pittosporum species (Pittosporaceae) [49]. Pentyl propanoate (fruity), which is a metabolic product derived from 1-pentanol, is an important flavoring ingredient formed by the condensation of pentanol and propanoic acid. The fruity smell of esters makes them unique, with wide applications in the flavor, fragrance, and solvent industries [50]. This compound is also found in truffles (Tuber canaliculatum) harvested in Quebec, Canada [51]. Alpha-Phellandrene (terpenic) is a compound found in the industrial product Monash Pouch diet, although its role in the flavor of this product is still unknown [52]. 3-Methylpentanoic acid (animal) receives special attention due to its peculiar aroma and its importance for fermented beverages. Acids can be obtained by lipid oxidation or by the conversion of aldehydes or ketones. Additionally, acids can react with alcohols to form esters and provide wine aroma, among them 3-methylpentanoic acid [53], which is also found in rice wine [54]. The presence of this compound seems to be stable in amounts in different wines [55] and has also been described in beers [56]. It is interesting to note that this aroma is present in the Brazilian SA, which can be very interesting for the country’s scenario. Recently, Brazil developed its first beer style, the Catharina sour. This style has been studied [57,58] and has already shown complexity in its volatile compound composition [20]. Thus, this could be a good hop for the local production of Catharina sour-style beers, even to enhance the flavor.

3.8. The Brazilian Touch in Hops

Regarding hops cultivated in Brazil, we observed a pattern, specifically compounds that were present in higher quantities or exclusively in all Brazilian-cultivated varieties. All varieties showed a higher amount of methyl 6-methylheptanoate (unrelated to aroma) and lower amounts of 3-(4-methylpent-3-enyl) furan (woody), linalool (floral), and 2-undecanone (fruity). Concerning exclusive compounds, none were found to be common in all varieties planted in Brazil. However, some are frequent in more than one hop. Pentyl propanoate (fruity), hexyl acetate (fruity), and 2-methylpropyl propanoate (fruity) were found in all hops except H. Mittelfrüher. Geranyl propionate (floral) was found in all except Magnum. Octyl acetate (floral) and octyl propanoate (fruity) were absent only in the German varieties H. Mittelfrüher and Magnum. Cis-3-hexenyl butyrate (green) and Geranyl acetate (floral) were absent only in the varieties H. Mittelfrüher and Sorachi Ace.

Regarding hops cultivated in their places of origin, isovaleric acid (cheesy) was the only exclusive compound found in all varieties. Dimethyl disulfide (sulfurous) was found in all except Sorachi Ace, while acetone (solvent) was found in all except Magnum, and dodecane (alkane) in all except H. Mittelfrüher. Methyl caproate (fruity), alpha-cadinol (herbal), and camphene (woody) were found in all American hops, possibly indicating a terroir effect.

H. Mittelfrüher and Magnum strains, which are German strains, have shown unique compounds compared to the German hop versus the Brazilian ones. Fourteen compounds are common between the H. Mittelfrüher and Magnum strains planted in Germany (Table 3), seven of which are aromatic, namely 2-methyl-1-butanol (ethereal); methyl isobutyrate (fruity); dimethyl disulfide (sulfurous); alpha-phellandrene (terpenic); isovaleric acid (cheesy); heptyl isobutyrate (fruity); and linalool oxide (earthy); while two compounds are common between the H. Mittelfrüher and Magnum strains planted in Brazil, namely alpha-muurolene (herbal) and beta-bisabolene (green).

It is given that H. Mittelfrüher and Magnum are both cultivated in the same region in Germany, known as Hallertau in Bavaria, and our Brazilian hop also originates from the same region. The cultivation in Germany would suggest a hop with more fruity, earthy, and cheesy notes, while in Brazil, it would suggest more herbal and green notes. Of course, further studies would be necessary to confirm this.

4. Conclusions

The analysis conducted through PLS-DA revealed significant variations in the aromatic profiles of hops cultivated in Brazil compared to their native counterparts, uncovering a total of 330 distinct volatile compounds. The differences in volatile compounds among the varieties, such as Hallertauer Mittelfrüher, Magnum, Nugget, Saaz, and Sorachi Ace, reflect the influence of terroir and cultivation conditions. Although the α-acid content of Nugget is similar between the Brazilian and American samples, the Magnum hop grown in Brazil stood out for its more fruity and floral profile. The Brazilian Saaz, on the other hand, exhibited an increase in α-acid content and fruity compounds compared to its Czech counterpart. These variations not only enrich the sensory complexity of beers but also open new opportunities for innovations in the industry, allowing brewers to select hops suitable for different styles, thereby enhancing the diversity and quality of the beverages produced.

Acknowledgments

The staff of the School of Pharmaceutical Sciences of the University of São Paulo for their support

Supplementary Materials

The following supporting information can be downloaded at https://www.mdpi.com/article/10.3390/plants13192675/s1: Table S1: Quantification of volatile compounds by Area% identified in the hops (Humulus lupulus) variety of Hallertauer Mittelfruher, Magnum, Nugget, Saaz, and Sorachi Ace, planted in Germany (DE), United States (USA), Czech Republic (CZ), and Brazil (BR).

plants-13-02675-s001.zip (142.6KB, zip)

Author Contributions

Conceptualization, M.E.H.; methodology, M.E.H. and O.B.; formal analysis, M.E.H. and O.B.; investigation, M.E.H. and O.B.; resources, M.E.H. and M.F.; data curation, M.E.H. and O.B.; writing—original draft preparation, M.E.H.; writing—review and editing, M.E.H., O.B. and M.F.; supervision, M.F.; project administration, M.E.H.; funding acquisition, M.E.H. All authors have read and agreed to the published version of the manuscript.

Data Availability Statement

Data are contained within the article and Supplementary Materials.

Conflicts of Interest

The authors declare no conflicts of interest.

Funding Statement

This research was funded by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), fellowships #2019/02583-0 and 2021/08621-0.

Footnotes

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