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Article

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

by
Marcos Edgar Herkenhoff
1,2,*,
Oliver Brödel
3 and
Marcus Frohme
3
1
Department of Biochemical and Pharmaceutical Technology, School of Pharmaceutical Sciences, University of São Paulo (USP), Av. Professor Lineu Prestes, 580, São Paulo 05508-000, SP, Brazil
2
Food Research Center FoRC, University of São Paulo (USP), Av. Professor Lineu Prestes, 580, São Paulo 05508-000, SP, Brazil
3
Division Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences Wildau, 15745 Wildau, Germany
*
Author to whom correspondence should be addressed.
Plants 2024, 13(19), 2675; https://doi.org/10.3390/plants13192675
Submission received: 30 August 2024 / Revised: 18 September 2024 / Accepted: 20 September 2024 / Published: 24 September 2024
(This article belongs to the Special Issue Plants as Food and Medicine)
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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.

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).
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).
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).
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.
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.

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).

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.

Funding

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

Data Availability Statement

Data are contained within the article and Supplementary Materials.

Acknowledgments

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

Conflicts of Interest

The authors declare no conflicts of interest.

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Plants 13 02675 g001aPlants 13 02675 g001b
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.
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.
Plants 13 02675 g001aPlants 13 02675 g001b
Plants 13 02675 g002
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).
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).
Plants 13 02675 g002
Table 1. Characteristics of the five hop (Humulus lupulus) varieties used in the present study.
Table 1. Characteristics of the five hop (Humulus lupulus) varieties used in the present study.
Hop StrainTypical UseCompanyOriginHarvestAlpha Acid (%) *
Hallertauer MittelfrüherAromaDalcinBrazil20216.88
Barth HaasGermany20204.50
MagnumBitterBrava TerraBrazil202112.81
Barth HaasGermany202014.70
NuggetBitterDalcinBrazil20219.66
Barth HaasUnited States20189.50
SaazAromaDalcinBrazil20215.67
Barth HaasCzech Republic20203.50
Sorcachi AceAroma/BitterBrava TerraBrazil20218.70
Barth HaasUnited States202010.80
* 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.
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.
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.
CompoundCAS #Retention IndexOdorFlavorH. MittelfrüherMagnumNuggetSaazSorachi Ace
TypeStrengthTypeDEBRDEBRUSABRCZBRUSABR
alpha-Pinene80-56-8948HerbalHighWoody
2-Methyl-1-butanol137-32-6697EtherealMediumEthereal
2-Methyl-1-Butanol1565-80-6697
beta-Pinene127-91-3943HerbalHighPine
Myrcene123-35-3958SpicyHighWoody
alpha-Phellandrene99-83-2969TerpenicMediumTerpenic
alpha-Terpinene99-86-5998WoodyMediumTerpenic
dextro-Limonene5989-27-51018CitrusMediumCitrus
alpha-Terpineol555-10-2964MintyMedium
Pentan-2-yl propanoate54004-43-2920
Methyl (E)-4-methylpent-2-enoate50652-78-3828
2-Pentene, 1-ethoxy-4-methyl-, (Z)-51149-75-8836
2-Methylpropyl 3-methylbutanoate589-59-3955FruityMediumGreen
Isoamyl isobutyrate2050-1-3955
2-Methylbutyl 2-methylpropanoate2445-69-4955Fruity
Ortho-cymene527-84-41042
1-Methyl-4-propan-2-ylidenecyclohexene586-62-91052HerbalMediumWoody
Methyl heptanoate106-73-0984Fruity Fruity
2-Octanone111-13-7952EarthyMediumDairy
3-Methylbut-2-enyl 2-methylpropanoate76649-23-51004Fruity
Methyl Methylenecyclohexanoate73805-48-8951
1-Octen-3-ol3391-86-4969EarthyHighMushroom
3-Methylbutyl 2-methylbutanoate27625-35-01054Fruity Fruity
2-Methylbutyl 2-methylbutyrate2445-78-51054Fruity Fruity
Isoamyl isovalerate2445-77-41054Fruity Fruity
Methyl 6-methylheptanoate2519-37-11019
Perillene539-52-61125WoodyMedium
Hexahydro-1,1-dimethyl-4-methylene-4H-cyclopenta[c]furan344294-72-01052
Hexyl 2-methylpropanoate2349-7-71054
Methyl octanoate111-11-51083Waxy Green
2-Methylpropyl hexanoate105-79-31118FruityMediumFruity
Benzaldehyde100-52-7982FruityHighFruity
2-Nonanone821-55-61052FruityMediumCheesy
4-Hydroxy-3-hexanone4984-85-4916
Octanol111-87-51059WaxyMediumWaxy
Linalool78-70-61082Floral MediumCitrus
Methyl 6-methyloctanoate5129-62-41118
Heptyl propanoate2216-81-11183Floral Fruity
Heptyl isobutyrate2349-13-51218Fruity Berry
Methyl nonanoate1731-84-61183Fruity Winey
Hexanoic acid142-62-1974FattyMediumCheesy
2-Methylbutyl hexanoate2601-13-01218Ethereal
alpha-Ylangene14912-44-81221
alpha-Copaene3856-25-51221Woody
2-Decanone693-54-91151FloralMediumFermented
Decyl trifluoroacetate333-88-01216
7-Decen-2-one35194-33-31159
Methylidenenonene55050-40-31156AldehydicMedium
5-methylhexanoic acid628-46-61009FattyMedium
2-(2,4-difluorophenyl)-1-[4-[6-(4-methylpiperazin-1-yl)pyridazin-3-yl]piperazin-1-yl]ethanone1191-2-2868
beta-Copaene18252-44-31216
2-Undecanone112-12-91251FruityMediumWaxy
beta-Caryophyllene87-44-51494SpicyMediumSpicy
(Z)-Undec-6-en-2-one107853-70-31259
Trans-geranic acid methyl ester1189-9-91054
(E)-beta-farnesene18794-84-81440Woody
alpha-Humulene6753-98-61579Woody
(Z,E)-alpha-Farnesene26560-14-51458
(-)-alpha-Muurolene10208-80-71440Woody
alpha-Selinene473-13-21474Amber
(3R,4aS,8aR)-8a-methyl-5-methylidene-3-prop-1-en-2-yl-1,2,3,4,4a,6,7,8-octahydronaphthalene17066-67-01469Herbal
alpha-Farnesene502-61-41458Woody Green
(-)-alpha-Gurjunene489-40-71419Woody
(-)-gamma-Cadinene39029-41-91435WoodyMedium
(+)-delta-Cadinene 483-76-11469Herbal
Zonarene41929-5-91440
Naphthalene, 1,2,3,4,4a,7-hexahydro-1,6-dimethyl-4-(1-methylethyl)-16728-99-71440
alpha-Cedrene24406-5-11440
Perilla alcohol18457-55-11261
2-Tridecanone593-8-81164
Geranyl Propionate105-90-81451FloralMediumWaxy
Calamenene483-77-21537Herbal SpicyMedium
Geranyl Butyrate106-29-61550FruityMediumFruity
(Z,Z)-1,8,11-heptadecatriene56134-3-31164
(Z)-3-decen-1-yl acetate81634-99-31389
Methyl ester 3,6-dodecadienoic acid16106-1-71164
Linalool oxide5989-33-31164EarthyMedium
beta-Calacorene50277-34-41542
Heneicosapentaenoic acid methyl ester65919-53-12415
Linolenyl Alcohol506-44-52077
2-n-Butyl-2-cyclopentenone5561_5-71280
1-Epi-cubenol19912-67-51580
beta-Caryophyllene oxide1139-30-61507WoodyMediumWoody
Isoascaridole19888-33-61592Herbal
Neointermedeol5945-72-21613
Humulene oxide II19888-34-71592
Methyl (8Z,11Z,14Z,17Z)-icosa-8,11,14,17-tetraenoate132712-70-02308
Cadalene483-78-31706
Caryophylla-4(12),8(13)-dien-5.alpha.-ol19431-79-91677
Methyl (Z)-5,11,14,17-eicosatetraenoate59149-1-81280
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.
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.
CompoundCAS #Retention IndexOdorFlavorH. MittelfrüherMagnumNuggetSaazSorachi Ace
TypeStrengthTypeDEBRDEBRUSABRCZBRUSABR
2-Methyl-1-butanol137-32-6697EtherealMediumEthereal
Methyl isobutyrate547-63-7621Fruity Ethereal
Dimethyl disulfide624-92-0722Sulfurous Sulfurous
alpha-Phellandrene99-83-2969TerpenicMediumTerpenic
Isovaleric acid503-74-2811CheesyHighCheesy
Heptyl isobutyrate2349-13-51218Fruity Berry
Linalool oxide5989-33-31164EarthyMedium
Acetone67-64-1455SolventHigh
Geranyl isovalerate109-20-61586FruityMediumGreen
alpha-Myrcene3338-55-4976FloralMediumGreen
Hexyl acetate142-92-7984FruityMediumFruity
Pentyl isobutyrate2445-72-91019Fruity
2-Nonanol628-99-91078Waxy Waxy
(-)-gamma-Elemene29873-99-21431GreenMedium
(-)-gamma-Cadinene39029-41-91435WoodyMedium
beta-Cadinene523-47-71440WoodyMedium
Neryl butyrate999-40-61550Green Green
Calamenene483-77-21537Herbal SpicyMedium
Isoascaridole19888-33-61592Herbal
Cedrol19435-97-31580HerbalMedium
alpha-Muurolene17699-14-81344Herbal
beta-Bisabolene28973-97-91440Green
Methyl Isovalerate23747-45-7940Cheesy Fermented
1-Hexanol111-27-3860Herbal Green
Beta-Myrcene502-99-8958FruityMedium
Methyl Heptenone110-93-0938CitrusMediumGreen
Isoamyl Isovalerate2445-77-41054Fruity Fruity
Methyl Nonenoate13481-87-31191FruityMediumFruity
Delta-3-Carene13474-59-41430Woody
Viridiflorol20307-83-91446HerbalMedium
Geranyl Propionate105-90-81451FloralMediumWaxy
Geranyl Butyrate106-29-61550FruityMediumFruity
Beta-Farnesene21391-99-11547WoodyMedium
Muscone37609-25-92072MuskMedium
Alpha-Phellandrene3779-61-1976Sweet HerbalMedium
Octyl Isobutyrate109-15-91317WaxyMediumCreamy
Methyl 2-Methylbutanoate868-57-5721Fruity Fruity
Methyl Isovalerate556-24-1721FruityMediumFruity
beta-Pinene127-91-3943HerbalHighPine
Methyl Caproate106-70-7884FruityMediumFruity
Ethyl Propanoate105-37-3686FruityHighFruity
2-Methyl-1-Butanol1565-80-6697
Isobutyl Isobutyrate97-85-8856Fruity Fruity
Ethyl Isohexanoate25415-67-2920Fruity
alpha-Terpineol555-10-2964MintyMedium
Dodecane112-40-31200Alkane
Methyl Octanoate15870-7-2884
Methyl 2-Methylheptanoate51209-78-01019
6-Methyl-5-Hepten-2-one49852-35-9896
2-Octanone111-13-7952EarthyMediumDairy
Methyl Methylenecyclohexanoate73805-48-8951
Beta-Pinene514-95-4992
Methyl 7-Methyloctanoate2177-86-81118
Octyl Acetate112-14-11183FloralMediumWaxy
Pentyl Cyclohexadiene56318-84-41143
Hexanoic Acid142-62-1974FattyMediumCheesy
7-Decen-2-one35194-33-31159
Methylidenenonene55050-40-31156AldehydicMedium
Octyl Propanoate142-60-91282Fruity Estery
Pentadecene13360-61-71502
beta-Cedrene30021-74-01435Woody
alpha-Cedrene24406-5-1992
Geranyl Isovalerate51117-19-21586
Linolenyl alcohol506-44-52077
Methyl 4-Methylpentanoate2412-80-8820Fruity Fruity
Carene3387-41-5897Woody Woody
Ethyl Hexanoate123-66-0984FruityHighFruity
Pentyl Propanoate624-54-4984Fruity Fruity
4-Pentenyl Butyrate30563-31-61073
5-Methylheptan-2-ol54630-50-1915
Ethyl 5-Methylhexanoate10236-10-91019
Methyl (E)-Hept-2-enoate22104-69-4992
(Z)-Hex-2-enyl Acetate56922-75-9992
Ethyl Octanoate106-32-11183WaxyMediumWaxy
beta-Bisabolene495-61-41500Balsamic
1-Methyloctyl acetate14936-66-41218
2,3,5-Trithiahexane42474-44-21072Sulfurous
Alloisolongifolene87064-18-41390
1-Tetradecene1120-36-11403
Ethyl trans-4-decenoate76649-16-61389GreenMediumFatty
Neryl isobutyrate2345-24-61486FruityMediumFruity
Methyl petroselinate2777-58-42085
Germacrene B15423-57-11603Woody
1-Tridecene2437-56-11304
Agarospirol1460-73-71598
Muurola-4,10(14)-dien-1 beta-ol257293-90-61586
Ethyl octanoate106-32-11183WaxyMediumWaxy
Trans-propionate 2-methyl-cyclohexanol15287-79-31208
2-Methylcyclohexyl butyrate15287-80-61307
3-Methylpentanoic acid105-43-1910Animal MediumSour
cis-3-Hexenyl butyrate16491-36-41191Green MediumGreen
(2S,4S)-2,4-Dimethylhexanoic acid methyl ester14251-45-7955
Ethyl heptanoate106-30-91083FruityMediumFruity
Hexyl propanoate2445-76-31083Fruity
Neo-alloocimene7216-56-0993
Methyl non-4-enoate20731-19-51191
2-Methyl-6-methyleneocta-2,7-dien-4-ol14434-41-41200
Eremophilene10219-75-71474
Geranyl acetate105-87-31352FloralMediumGreen
Gamma-maalinene20071-49-21398
(-)-Aristolene6831-16-91403
2-Tetradecanone2345-27-91549
trans-Nerolidol40716-66-31564FloralLowGreen
1-cyclododecyl-ethanone28925-0-0955
Linolenyl alcohol506-44-52077
alpha-Cadinol481-34-51580HerbalMedium
2,2,4,6,6-pentamethylheptane13475-82-6981
Butyl nitrite544-16-1609
1-Pentanol71-41-0761Fermented Fusel
2-methylbutyl propanoate2438-20-2920Fruity
Benzaldehyde100-52-7982FruityHighFruity
6-methylheptanoic acid929-10-21109
5-Nonenoic acid methyl ester20731-20-81191
Heptanoic acid111-14-81073Cheesy Waxy
Neryl isobutyrate2345-24-61486FruityMediumFruity
Perillyl alcohol536-59-41261GreenMediumWoody
Isopentyl 8-methylnon-6-enoate1215128-16-71559
4,8,11,11-tetramethylbicyclo[7.2.0]undec-3-en-5-ol913176-41-71677
(6Z,9Z,12Z,15Z)-Methyl octadeca-6,9,12,15-tetraenoate73097-0-4943
Bicyclo[3.1.1]hept-2-ene, 2,6-dimethyl-6-(4-methyl-3-pentenyl)-17699-5-71474
Methyl 5-methyl-2-hexenoate68797-67-1928
4,6-Dimethyloctanoic acid2553-96-01154
1,3-Nonadiene56700-77-7914
Camphene79-92-5943WoodyMediumCamphoreous
alpha-Terpinene99-86-5998WoodyMediumTerpenic
Borneol464-45-91138BalsamicMediumCamphoreous
10-Epizonarene41702-63-01469
alpha-Farnesene502-61-41458Woody Green
(+)-delta-Cadinene 483-76-11469Herbal
Naphthalene, 1,2,3,4,4a,7-hexahydro-1,6-dimethyl-4-(1-methylethyl)-16728-99-71440
1-Octadecene112-88-91801
(2Z,6E)-Farnesol3790-71-41710
4-methyl-5-propylnonane62185-55-11185
3-Methylbut-2-enyl 2-methylpropanoate76649-23-51004Fruity
2,6-dimethyl-1,3,5,7-octatetraene, E,E-460-1-5955
Heptyl propanoate2216-81-11183Floral Fruity
alpha-Guaiene3691_12-11054Woody
Methyl linolelaidate2462-85-3955
Methyl dodecanoate111-82-01481WaxyMediumWaxy
Methyl decanoate110-42-91282Fermented Fatty
2-methylpropyl propanoate540-42-1955Fruity Fruity
Pentan-2-yl propanoate54004-43-2920
3-methylbutyl 3-methylbutanoate659-70-11054FruityMediumGreen
S-propyl hexanethioate2432-78-21303
(Z)-Undec-6-en-2-one107853-70-31259
(-)-alpha-Gurjunene489-40-71419Woody
.alpha.-Maaliene489-28-11403
Methyl petroselinate2777-58-42085
Perilla alcohol18457-55-11261
Heneicosapentaenoic acid methyl ester65919-53-12415
2,2-dimethyldecane17302-37-31130
3-methylbut-2-enal107-86-8692Fruity Fruity
3,5-dimethyl-1,6-heptadiene68701-99-5768
(Z)-9-methylundec-5-ene74630-65-21158
Methyl (E)-4-methylpent-2-enoate50652-78-3828
(Z)-hex-3-en-1-ol928-96-1868GreenHighGreen
2-methylbutanoic acid116-53-0811AcidicMediumFruity
Methyl 2,4-dimethylnonanoate54889-61-11253
2-methyl-6-methylene-2-octene10054-9-81054
3,3-dimethylcyclohexan-1-one2979-19-31025
Decyl trifluoroacetate333-88-01216
2-Nonanone821-55-61052FruityMediumCheesy
Fenchol1632-73-11138CamphoreousMediumCamphoreous
11,14-Eicosadienoic acid, methyl ester2463_02-71054
beta-Bisabolene495-61-41500Balsamic
(E)-alpha-bisabolene25532-79-01518
3-(1,1-dimethylethyl)-2,5-furandione18261-7-91054
1-methyl-3-propan-2-ylbenzene535-77-31042
Methyl (Z)-octadec-9-enoate112-62-92085Mild fattyLow
trans-Furan linalool oxide34995-77-21164FloralMedium
3-methoxybutan-2-ol53778-72-6692
alpha-Pinene80-56-8948HerbalHighWoody
Butyl 2-methylpropanoate97-87-0920Fruity Fruity
2-Methylpropyl 3-methylbutanoate589-59-3955FruityMediumGreen
Isoamyl isobutyrate2050-1-3955
(Z)-3-hexen-1-yl acetate3681-71-8992GreenHighGreen
Methyl (2S,4R)-2,4-dimethylheptanoate18450-78-71054
2-methylpent-4-en-1-ol5673-98-3786
[(Z)-hex-3-enyl] 2-methylbutanoate53398-85-91226GreenMediumGreen
Methyl 10-undecenoate111-81-91371Fatty Waxy
alpha-Selinene473-13-21474Amber
2-Isopropenyl-4a,8-dimethyl-1,2,3,4,4a,5,6,7-octahydronaphthalene103827-22-11502
Geraniol106-24-11228FloralMediumFloral
Methyl ester 3,6-dodecadienoic acid16106-1-71164
2-hexadecyloxirane7390-81-01054
Neryl propionate105-91-91451FruityMediumGreen
Aplotaxene10482-53-81725Costus
2-Nonadecanone629-66-32046
Methyl 7Z-hexadecenoate56875-67-31886
Methyl (8Z,11Z,14Z,17Z)-icosa-8,11,14,17-tetraenoate132712-70-02308
Prenol556-82-1746Fruity Fruity
Isobutyl 2-methylbutyrate2445-67-2955Fruity Fruity
Ortho-cymene527-84-41042
Methyl heptanoate106-73-0984Fruity Fruity
2-Methylbutyl 2-methylbutyrate2445-78-51054Fruity Fruity
Heptyl ester acetic acid112-6-11054
hexyl 2-methylpropanoate2349-7-71054
Methyl octanoate111-11-51083Waxy Green
Mesityl oxide141-79-7739Vegetable Potato
2-Heptanone110-43-0853CheesyHighCheesy
3-Methylbutyl propanoate105-68-0920FruityMediumFruity
1-Dodecene112-41-41204
1-Cyclohexyl-2-buten-1-ol79605-62-21249
2-Methylpropyl hexanoate105-79-31118FruityMediumFruity
1,1-Cyclohexanedimethanol2658-60-81339
2-Methyl-2-(4-methyl-3-pentenyl)-cyclopropanemethanol98678-70-71280
2-Methyl-2-pentenoic acid16957-70-31054FruityMedium
(1S,4S,4aS)-1-Isopropyl-4,7-dimethyl-1,2,3,4,4a,5-hexahydronaphthalene267665-20-31440
Calarene17334-55-31403
Cyclodecene3618-12-01181
Alpha-dehydro-ar-himachalene78204-62-31601
2-ethylidene-1,7,7-trimethylbicyclo[2.2.1]heptane62413-60-91134
2-n-Butyl-2-cyclopentenone5561_5-71054
beta-Caryophyllene oxide1139-30-61507WoodyMediumWoody
(-)-Camphene5794_04-71280
5-Methylhexan-3-one623-56-3789
2-Pentene, 1-ethoxy-4-methyl-, (Z)-51149-75-8836
(E)-hex-4-en-1-ol928-92-7868Green Green
Di(imidazol-1-yl)methanone530-62-11445
Ethyl 3-hexenoate2396-83-0992FruityMediumFruity
2-methylbutyl butanoate51115-64-11019Fruity Fruity
1-Heptanol111-70-6960GreenMediumSolvent
Methyl nonanoate1731-84-61183Fruity Winey
2-Methylbutyl hexanoate2601-13-01218Ethereal
2-methyl-6-methylideneocta-1,7-dien-3-one41702-60-71076
3,5-Dimethyl-1,6-heptadiene68701-99-5768
Nalpha,Nomega-Dicarbobenzoxy-L-arginine53934-75-13543
2-(2,4-difluorophenyl)-1-[4-[6-(4-methylpiperazin-1-yl)pyridazin-3-yl]piperazin-1-yl]ethanone1191-2-2868
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Herkenhoff, M.E.; Brödel, O.; Frohme, M. 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. Plants 2024, 13, 2675. https://doi.org/10.3390/plants13192675

AMA Style

Herkenhoff ME, Brödel O, Frohme M. 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. Plants. 2024; 13(19):2675. https://doi.org/10.3390/plants13192675

Chicago/Turabian Style

Herkenhoff, Marcos Edgar, Oliver Brödel, and Marcus Frohme. 2024. "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" Plants 13, no. 19: 2675. https://doi.org/10.3390/plants13192675

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