Next Article in Journal
Hydrophobicity Enhances the Formation of Protein-Stabilized Foams
Next Article in Special Issue
The Elemental Profile of Beer Available on Polish Market: Analysis of the Potential Impact of Type of Packaging Material and Risk Assessment of Consumption
Previous Article in Journal
Smart Titanium Wire Used for the Evaluation of Hydrophobic/Hydrophilic Interaction by In-Tube Solid Phase Microextraction
Previous Article in Special Issue
Melatonin in Brassicaceae: Role in Postharvest and Interesting Phytochemicals
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Elucidation of Analytical–Compositional Fingerprinting of Three Different Species of Chili Pepper by Using Headspace Solid-Phase Microextraction Coupled with Gas Chromatography–Mass Spectrometry Analysis, and Sensory Profile Evaluation

1
Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Annunziata, 98168 Messina, Italy
2
Chromaleont s.r.l., c/o Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Annunziata, 98168 Messina, Italy
3
Mediterranean Food Science, Lungarno della Zecca Vecchia 28, 50122 Firenze, Italy
4
Department of Sciences and Technologies for Human and Environment, University Campus Bio-Medico of Rome, Via Alvaro del Portillo 21, 00128 Rome, Italy
*
Author to whom correspondence should be addressed.
Submission received: 23 February 2022 / Revised: 25 March 2022 / Accepted: 4 April 2022 / Published: 6 April 2022

Abstract

:
The aim of the present study was to determine the volatile compounds of three different species of chili peppers, using solid-phase microextraction (SPME) methods in combination with gas chromatography–mass spectrometry (GC-MS). The detection of marker aroma compounds could be used as a parameter to differentiate between species of chili peppers for their detection and traceability in chili pepper food. The sensorial contribution was also investigated to identify the predominant notes in each species and to evaluate how they can influence the overall aroma. Three different pepper species belonging to the Capsicum genus were analyzed: Chinense, Annuum, and Baccatum. A total of 269 volatile compounds were identified in these species of chili peppers. The Capsicum annum species were characterized by a high number of acids and ketones, while the Capsicum chinense and Capsicum baccatum were characterized by esters and aldehydes, respectively. The volatile profile of extra virgin olive oils (EVOOs) flavored with chili peppers was also investigated, and principal component analysis (PCA) and hierarchical cluster analysis (HCA) of the volatile profiles were demonstrated to be a powerful analytical strategy for building a model that highlights the potential of a volatile characterization approach for use in evaluating food traceability and authenticity.

1. Introduction

Chili peppers are used as food or spice and are widely used by the food industry as an ingredient for different kinds of flavored and spiced products. The genus Capsicum comprises five species: Capsicum annuum (containing NuMex, Jalapeno, and Bell varieties), Capsicum frutescens (containing the Tabasco variety), Capsicum chinense (containing the Habanero and Scotch Bonnet varieties), Capsicum baccatum (containing the Aji varieties), and Capsicum pubescens (containing the Rocoto and Manzano varieties) [1]. Even though the volatile profile of chili peppers belonging to the Capsicum annuum species has been analyzed, the volatile profile of C. baccatum has not been well investigated [2]. Furthermore, volatile compounds in C. chinense were identified and quantified as in previous articles [3,4,5,6,7,8], but no direct comparison between the volatile profile of different C. chinense peppers and other pepper species has been made.
The aim of the present study was to analyze, by using solid-phase microextraction–gas chromatography (SPME-GC), the volatile profiles of 17 pepper varieties belonging to three of the five major cultivated species to assess the quality of the analyzed cultivars and to determine the marker compounds responsible for their aromatic characteristics and thus identify them as additives in food products.
Most of the studies presented in the literature were limited to the identification of volatiles without any sensorial tests, and therefore, the real contribution of individual compounds to the overall aroma has not been accurately established. In this respect, the sensory profile of chili peppers was also investigated in order to find a correlation with volatile components and to evaluate which notes contribute the most to the perceived aroma.
Furthermore, the volatile profile of chili-pepper-flavored foods has not been investigated in depth, and the results regarding the capsaicinoids content have mostly been investigated. For this reason, the volatile profile of three commercial extra virgin olive oils (EVOOs) flavored with chili pepper was examined by gas chromatographic analysis, comparing their profile with that of conventional unflavored extra virgin oils.
The linear retention index (LRI) system was used as a supplementary tool for the recognition of the compounds in combination with the mass spectra, and it made possible the reliable identification and accurate quantification of volatiles in chili peppers and chili-pepper-flavored olive oils.

2. Results and Discussion

2.1. Samples Analyzed

A total of seventeen fresh chili pepper samples belonging to the genus Capsicum were collected at the same growth phase in their full ripening stage and kindly provided by Azienda Agricola Salvadori Rita (Livorno, Italy). After their arrival, all the chili peppers were frozen until the day of the analysis and analyzed within two weeks from the freezing process. For each species, three whole chili peppers were ground together, and four homogenized samples were weighted in SPME vials, one for GC-MS and three for GC-FID analysis, assuming the analytes identified were a mean of their content in each pepper. The vials were closed and put in the fridge until the analyses, which were carried out consecutively on the same day. Three chili pepper extra virgin olive oils were purchased online. From the information reported on the label, one of them was flavored with Merkén pepper (a smoked Aji chili pepper), the second was flavored with a mix of Capsicum chinense peppers, and the third was flavored with the addition of a mix of different chili peppers. For convenience, the three extra virgin flavored olive oils samples were called EVOO1, EVOO2, and EVOO3, respectively. Table 1 lists the investigated samples.

2.2. Volatile Fraction Analysis

The analyzed chili samples displayed different gas chromatography–mass spectrometry (GC-MS) chromatograms. Figure 1, Figure 2 and Figure 3 show an example of a chromatogram for each variety. More than two hundred and fifty compounds were identified in total in the different samples, accounting for 87–91% of the total composition (Table 2 and Table S1 from Supplementary Materials). Table 2 reports volatile compounds with a percentage area greater than 0.5% in at least one of the chili peppers samples analyzed, and Table S1 from Supplementary Materials reports the other volatile compounds with a percentage area less than 0.5%.
Volatile organic compounds (VOC) are commonly correlated with food flavor and fragrance, and their determination is important to evaluate food quality, authenticity, purity, and origin [9]. Methyl and ethyl esters, for example, provide strong fruity notes in foods, whereas terpenes provide woody, floral, fruity, and spicy notes. Aldehydes have a low odor threshold, and the sniffing analysis of Capsicum reported their presence as green, cucumber, pungent, or herbaceous odor notes [10,11].
In addition, it has been proven that the volatiles’ profile of Capsicum is mainly affected by varieties [5], ripening stages [3], and processing [12].
The analyses carried out on Capsicum chinense peppers revealed that the most relevant compounds are esters (4-methylpentyl 3-methylbutanoate, 6-methylhept-4-en-1-yl 3-methylbutanoate, 4-methylpentyl 2-methylbutanoate, hexyl 3-methylbutanoate, (Z)-3-hexenyl 2-methylbutanoate, 2-methylbutyl 8-methylnon-6-enoate, 6-methylhept-4-en-1-yl 2-methylbutanoate, heptyl isovalerate, 4-methylpentyl 4-methylpentanoate, 6-methylheptyl 3-methylbutanoate, and (Z)-3-hexenyl 3-methylbutanoate) (Figure 1).
The presence of several aliphatic esters in the C. chinense variety has been reported in the literature [3,4,5,6]; it has been confirmed that esters, especially straight-chain esters, are generally metabolized from fatty acids through oxidation [13], and that branched saturated and non-saturated esters can be derived from amino acids’ metabolism [5].
Among the analyzed C. chinense samples, Habanero red savina, Habanero chocolate, and Scotch bonnet showed a lower content of esters and a greater amount of alcohols and aldehydes (Figure 4). It has been demonstrated that ester biosynthesis is limited by alcohol concentration, which can modify the content of esters in specific cultivars [14]. In the analyzed species, even if there is good alcohol availability, the production of the esters is probably inhibited by the absence of free fatty acids.
Literature data on the Capsicum Chinese variety [3,4] report the presence of a little amount of 2-isobutyl-3-methoxypyrazine in the Habanero peppers variety (0.01 mg kg−1). Effectively, the three Habanero chili peppers analyzed in the present study did not present this compound (Habanero fatalii (sample 3) and Habanero red savina (sample 7)), or had a very little quantity (Habanero chocolate (sample 8) (0.06%)) of 2-isobutyl-3-methoxypyrazine, which was mainly detected in the Scotch Bonnet variety (sample 9) (0.52%).
The volatile profile of the analyzed Capsicum annuum samples was principally characterized by acids, in particular acetic; aldehydes ((E)-2-hexenal, n-hexanal, 2-methylbutyraldehyde, and isovaleric aldehyde); ketones (acetoin and 3-methyl-2-butanone); alcohols (4-methyl-1-pentanol and isoprenol); and esters (4-methylpentyl 3-methylbutanoate and 4-methylpentyl 2-methylbutanoate) (Table 2 and Table S1 and Figure 2 and Figure 4).
Terenzio and Calabrian pepper varieties showed a greater abundance of (E)-2-hexenal than the others belonging to the same species. Only the Jalapeňo pepper contained 6-Methylhept-4-en-1-yl 2-methylbutanoate and 6-Methylhept-4-en-1-yl 3-methylbutanoate.
Banana and the Jalapeňo chili pepper showed the highest amount of acids, followed by Cayenna impala, Terenzio, and Calabrian varieties.
Regarding alcohols, the Calabrian pepper is the only one distinguished by a great percentage of (E)-3-hexenol (8.99%).
Concerning terpenoids, the Banana pepper showed the highest amount of (E)-β-ocimene, which is absent in the Calabrian pepper. The latter, however, has a higher content of α-longipinene, which is absent in Banana and Cayenna pepper varieties. The Cayenna pepper presented a high amount of α-copaene and β-chamigrene. The latter was also found in larger amounts in the Calabrian pepper. The Jalapeňo chili pepper is the only one with an amount of (E)-α-bergamotene greater than 1%.
Furthermore, the Cayenna Impala variety presented a higher amount of 2-isobutyl-3-methoxypyrazine than the other samples. This compound was found to possess an extremely potent odor (odor threshold of 2 × 10−6 mg kg−1), similar to that of fresh green bell peppers [15].
Regarding Capsicum baccatum chili peppers, a great contribution to the volatile profile is given by alcohols (n-hexanol, (E)-3-hexenol, (E)-2-hexenol, (Z)-2-buten-1-ol); aldehydes ((E)-2-hexenal, n-hexanal, 4-methyl-2-pentenal); and esters (ethyl hexanoate, isobutyl 8-methylnon-6-enoate, 4-methylpentyl 3-methylbutanoate, 4-methylpentyl 3-methylbutanoate, ethyl lactate) (Table 2, Table S1 and Figure 3).
The Aji variety has higher ketones, esters, and terpenes contents than the other chili peppers of the same species. The high percentage area encountered for terpenes, ketones, and esters is relative to (E)-β-ocimene, 3-pentenone, and isopropyl acetate, respectively. The Erotic and Jimmi varieties are similar in respect to the amount of aldehydes, ketones, and hydrocarbons identified.
Compounds, such as α-ionone and β-ionone, which may be formed by oxidative degradation of δ-carotene, β-carotene, and terpenoids [16], were particularly found in orange peppers belonging to this third species.
Although the literature reports several studies on the aroma and the content of capsaicinoids in chili peppers [17], to the best of our knowledge, capsaicinoids [18,19] and the volatile profile of chili-pepper-flavored extra virgin olive oil have not been investigated well [19]. For this reason, a study on the aroma profile of flavored EVOOs was carried out and compared to that of fresh peppers and unflavored olive oils. Table S2 reports the results of the volatile compounds identified in the flavored olive oils.

2.3. Statistical Analysis

PCA was performed on the 118 most abundant volatile compounds identified in chili peppers (Figure 5A) and on the same numbers of volatiles, also including the data acquired for chili-pepper-flavored extra virgin olive oils (Figure 5B). For statistical data treatment, the following conditions were applied: original values are ln(x)-transformed; rows are centered; Pareto scaling is applied to rows; SVD with imputation is used to calculate principal components.
As shown in Figure 5A, the PCA score plot in the space of the two PCAs explains 56.0% of the total variance, only considering the peppers, and 49.0% of the total variance, also considering the oils (Figure 5B). This confirms the applicability of the built model and the other unknown samples. From Figure 5, it is clear that at positive values of PC1 and negative values of PC2, the Capsicum baccatum species is well separated, whereas the Capsicum annuum is present at negative values of PC1 and PC2. Furthermore, the Capsicum chinense species is separated well on PC1 in the positive region. As far as the PC2 shown in Figure 5B is concerned, it is interesting to notice that the extra virgin olive oils EVOO1 (containing Merkén pepper, a smoked Aji chili pepper belonging to Capsicum baccatum) and EVOO2 (containing a mix of the Capsicum chinense pepper) are correctly grouped with the peppers used as a flavoring in the producing process. Since the EVOO3 samples were flavored with a mix of Capsicum belonging to different species, it is not possible to insert them into a specific group. Table S4 from Supplementary Materials lists the compounds that mainly influence the plot and their contribution to PC1 and PC2.
Hierarchical cluster analysis (HCA) was performed using both the relative percentage area of the class of the compound identified (Figure S1 from Supplementary Materials) and the relative percentage area of the most abundant volatiles (118) (Figure S2 from Supplementary Materials).
The cluster analysis based on the identified compounds class showed an overlap between the different species; consequently, it is not possible to distinguish between different Capsicum species by only considering their contribution (Figure S1 from Supplementary Materials).
The cluster analysis based on the patterns of the most abundant volatiles instead showed good separation of C. chinense from the C. annuum and C. baccatum group (Figure S2 from Supplementary Materials).
In accordance with PCA analysis, HCA built by introducing the volatile patterns of the three flavored olive oils shows the EVOO2 sample grouped with Capsicum chinense peppers and EVOO1 grouped with the Capsicum baccatum species, confirming the goodness of the model (Figure 6). In addition, the results confirm the information on the labels of EVOO1 and EVOO2 and guarantee the quality of commercial products, confirming the usefulness of the model for this purpose.

2.4. Sensorial Analysis

With regard to the aroma, the sensorial test revealed a wide range of odor impressions in the 17 varieties of chili peppers examined.
The chili peppers belonging to the C. chinense species were mainly characterized by exotic, fruity, and/or sweet notes (Figure 7 and Figure S3 from Supplementary Materials), and their aromas were the most intense among all samples investigated. Such notes are due to the presence of numerous esters, especially 4-methylpentyl 3-methylbutanoate and 4-methylpentyl 2-methylbutanoate [20], Hexyl 3-methylbutyrate, (Z)-3-Hexenyl 3-methylbutyrate, and (Z)-3-Hexenyl 2-methylbutyrate. The dairy, buttery, and creamy notes found in some peppers, such as Naga morich, Habanero fatalii, Naga chocolate, Trinidad scorpio moruga yellow, Habanero red savina, Scotch bonnet, and Habanero chocolate, are due to the presence of some ketones such as acetoin [21,22], and especially medium-short chain fatty acids such as n-decanoic, which characterizes the base note of the Habanero fatalii.
The sweet note of vanilla perceived in the Scotch Bonnet is confirmed from an analytical point of view by the presence of guaiacol, a compound that characterizes the vanilla beans [21,22].
Similarly, the note of “wintergreen” (Gaultheria procumbens) found in the Scotch Bonnet and Habanero Fatalii is confirmed by the presence of methyl salicylate in the volatile profile [21,22].
In contrast, C. annuum and C. baccatum showed different intensity and aroma profiles with a medium-intense mixture of fruity and vegetable-like notes (Figure 7 and Figures S4 and S5 from Supplementary Materials) due to the presence of (E)-2-hexenal in both species, and also depending on isopentyl alcohol and n-hexanol in C. annuum and C. baccatum, respectively.
The persisting final perceived note of cheese in C. annuum is dependent on n-isovaleric acid [21,22]. Additionally, in some chili peppers belonging to C. baccatum, such as the Banana pepper and Cayenna impala, dairy and blue cheese notes were found due to the presence of n-hexanoic acid, but they do not really affect the perceived aroma on the olfactory level.
In the peppers belonging to the C. baccatum species, the fruity notes are predominant, in particular the green and yellow apple typical of (E)-2-hexenal and pentyl isovalerate [21,22], respectively, and the perceived aroma is generally light.

3. Materials and Methods

3.1. Standard Compounds (Reagents)

A C7–C40 Saturated Alkanes (1000 μg/mL) standard mixture in hexane (49452-U) supplied by Merck Life Science (Darmstadt, Germany) was utilized for ALKANEs linear retention indices (LRIs) calculation. Forty-seven standard compounds (Table S3 from Supplementary Materials) supplied by Merck Life Science (Darmstadt, Germany) were used for the training of the panelist for sensory analysis.

3.2. SPME Extraction Conditions

For the method optimization, two SPME fibers supplied by Merck Life Science (Darmstadt, Germany) were tested: carboxen/polydimethylsiloxane (CAR/PDMS), 75 μm 1 cm long (57343-U), and divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS), 50/30 μm 1 cm long (57329-U). The fibers were conditioned before the initial use according to manufacturer’s instructions, and a cleaning step of 20 min at 10 °C below fiber recommended maximum temperature was applied between consecutive analyses. GC analyses were carried out using for each test a 10 mL vial with 0.2, 0.3, and 0.4 g of ground sample, respectively, inserting the fiber 2 cm above the sample, and the best results were obtained for a 0.2 g sample weight.
Four different fiber exposure times were tested: 30, 40, 50, and 60 min. The highest volatile extraction yield was achieved after an exposure time of 50 min, and most of the heavier molecular weight volatiles remained substantially stable thereafter. Furthermore, a sample conditioning time of 5 and 10 min was evaluated at the same temperature (30 °C, 40 °C, 50 °C, or 60 °C) employed for the extraction stage, and the analytical repeatability was excellent in both conditions. Different stirring rates (200 and 300 rpm) for sample conditioning and extraction were also investigated.
In this investigation, the (DVB/CAR/PDMS) 50/30 μm fiber was found to be the most useful in covering the wide range of chili pepper volatile analytes; a conditioning time of 5 min and an extraction temperature of 50 °C were the best compromise between equilibration time and method sensitivity. Furthermore, a time of 50 min at the same temperature and stirring rate of 300 rpm were proven to be the best choices for an exhaustive extraction of the volatiles components (Figures S6–S10 from Supplementary Materials show method optimization).
The same extraction condition was adopted for the flavored extra virgin olive oils, using 1 mL as sample volume.
After the extraction, the analytes were manually injected in splitless mode and thermally desorbed for 1 min at 260 °C in the GC injector port.

3.3. GC–MS and GC-FID Analysis

GC-MS and GC-FID analyses were carried out for qualitative and quantitative purposes, respectively.
GC-MS analyses were carried out on a GC-QP2020 system (Shimadzu, Kyoto, Japan). For the separation, an SLB-5 ms fused-silica capillary column (30 m × 0.25 mm i.d. × 0.25 μm df) (29804-U) (Merck KGaA, Darmstadt, Germany) was applied. Helium was used as carrier gas at a constant linear velocity of 30.0 cm/s, which corresponded to an inlet pressure of 24.2 kPa. An inlet liner, direct SPME type, straight design unpacked (2633501) (Merck KGaA, Darmstadt, Germany) was used. The injector was equipped with a Thermogreen LB-2 Septa, plug (20608) (Merck KGaA, Darmstadt, Germany), and the temperature was set at 260 °C. The temperature program was the following: 40 °C, held for 1 min, to 350 °C at 3 °C/min, held for 5 min. The interface and ion source temperatures were 250 °C and 200 °C, respectively. The acquisition was made in full scan mode in the mass range of 40–500 m/z, with a scanning rate interval of 0.2 s. Data handling was supported by GCMS solution ver. 4.30 software (Shimadzu, Kyoto, Japan). For the characterization, the following databases were used: W11N17 (Wiley11-Nist17, Wiley, Hoboken, NJ, USA; and FFNSC 4.0 (Shimadzu, Kyoto, Japan). The identification was performed applying two filters, namely, spectral similarity match over 85% and linear retention index (LRI) match calculated using a C7–C40 saturated n-alkane homolog series with a filter window of ±10 LRI units.
The LRIs were calculated applying the equation proposed by H. Van den Dool and D. J. Kratz (Equation (1)) [23], developed for programmed-temperature retention index calculation.
L R I = 100 × [ z + ( t R i t R z ) / ( t R ( Z + 1 )   t R z ) ]
GC-FID analyses were carried out on a GC2010 system (Shimadzu, Kyoto, Japan). Column, oven temperature program, and injection parameters were the same as for MS applications. Helium was used as carrier gas at a constant linear velocity of 30.0 cm/s, which corresponded to an inlet pressure of 97.4 kPa. The FID temperature was set at 280 °C (sampling rate 200 ms), and hydrogen and air flows were 40 mL/min and 400 mL/min, respectively. Data were collected by LabSolution software ver. 5.92 (Shimadzu, Kyoto, Japan). Quantitative results were determined as peak area percentage without any correction. Samples were analyzed in triplicates.

3.4. Statistical Procedure

Principal components analysis (PCA) bidimensional visualization, as implemented in ClustVis large version 2.0 (https://biit.cs.ut.ee/clustvis_large, accessed on 25 March 2022), was used for showing relationships between compounds classes and metabolites with Capsicum chili peppers species, respectively. For these analyses, the compounds classes and metabolite datasets were ln (x + 1) transformed and mean-centered. Pareto scaling was used as a measure for compounds’ classes–species and metabolite–species correlation and for hierarchical clustering analysis (HCA).

3.5. Sensorial Evaluation Procedure

Sensory analysis was carried out by a panel of 7 analysts trained to distinguish and describe the aroma characteristics of 47 pure standards (Table S3 from Supplementary Materials). The first step was to carry out a screening of all the chili pepper samples to identify the descriptors. The overall aroma of accessions was defined by about 61 descriptors, divided into 4 macro-areas: fresh fruity and floral notes; fresh vegetable notes; dry vegetable notes; and other notes (miscellaneous), including woody, dairy, spicy, and notes not attributable to the other categories. Figure S11 from Supplementary Materials reports a list of the descriptors identified by the panel test.
For the sensorial analysis, the peppers were chopped one at a time with an immersion blender to reduce them into pieces of 2/3 mm, and the mixture was then placed on a sheet of absorbent paper to drain the moisture. Each panel smelled the preparation for about 30 min in order to identify the top, the middle, and the bottom notes.
The intensity of the previously identified descriptor was judged on a 10-point scale from 1 = weak to 10 = very strong. The radar graphs for each sample were constructed with the positive average values, excluding the values equal to zero, the minimums, and maxima.

4. Conclusions

In this paper, the volatile fingerprinting of 17 varieties of chili peppers belonging to Capsicum chinense, Capsicum annuum, and Capsicum baccatum were profiled using an HS-SPME extraction method followed by GC analysis. Previously, Capsicum baccatum’s volatile profile was not well investigated. Furthermore, this is the first work in which such a large number of chili peppers belonging to Capsicum chinense is analyzed and discussed in detail.
The diversity in aroma found among the studied cultivar, due to qualitative and quantitative differences of the odor-contributing volatiles, was also confirmed by the sniffing test. In particular, the sensory results revealed C. chinense chili peppers have fruity/exotic aromas and are characterized by a high contribution of several esters. The aroma found among C. annuum is due to different combinations of fruity/exotic and green/vegetable notes. The notes perceived in Capsicum baccatum peppers are principally fruity, and their intensity is weak in respect to that of the other pepper species.
Principal components analysis and hierarchical cluster analysis performed using percentage area of the 118 most abundant volatile compounds enabled a model to be built to distinguish between the different Capsicum species investigated. In addition, the volatile profile of chili extra virgin olive oil was investigated in order to find a valuable approach providing useful and comprehensive insights to evaluate the impact of chili flavor addition on extra virgin olive oil’s volatile composition, which highlights the use of this approach for evaluating food traceability and authenticity.

Supplementary Materials

The following supporting information can be downloaded at: https://0-www-mdpi-com.brum.beds.ac.uk/article/10.3390/molecules27072355/s1, Figure S1: Hierarchical cluster analysis based on the relative percentage areas of identified compound classes; Figure S2: Hierarchical cluster analysis based on the relative percentage areas of the 118 most abundant identified volatiles; Figure S3: Aroma profile of the Capsicum chinense pepper from descriptive sensory analysis on the line scale (n = 10); Figure S4: Aroma profile of the Capsicum annuum pepper from descriptive sensory analysis on the line scale (n = 10); Figure S5: Aroma profile of the Capsicum baccatum pepper from descriptive sensory analysis on the line scale (n = 10); Figure S6: Influence of temperature on SPME method extraction optimization; Figure S7: Influence of time on SPME method extraction optimization; Figure S8: Influence of stirring rate on SPME method extraction optimization; Figure S9: Influence of sample time conditioning on SPME method extraction optimization; Figure S10: Influence of sample volume on SPME method extraction optimization; Figure S11: List of descriptors used in the sensory analysis of chili peppers; Table S1: Less abundant volatile compounds contained in the chili peppers samples analyzed, expressed in area % as a GC-FID measurement; Table S2: Volatile compounds contained in the chili-pepper-flavored olive oil samples analyzed, expressed in area % as a GC-FID measurement result; Table S3: Standard key compounds used for the training of panelists for sensorial analysis; Table S4. Contribution of the variables on PC1 and PC2.

Author Contributions

Conceptualization, E.T.; methodology, D.C. and E.T.; formal analysis, F.V.; investigation, E.T. and F.V.; data curation, E.T.; writing—original draft preparation, E.T.; writing—review and editing, E.T.; supervision, L.M. and P.D. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Acknowledgments

The authors gratefully acknowledge the Azienda Agricola Salvadori Rita (Livorno, Italy); which provided chili peppers samples; the Shimadzu Corporation; and Merck Life Science (Merck KGaA, Darmstadt, Germany) for their continuous support.

Conflicts of Interest

The authors declare no conflict of interest.

Sample Availability

Samples from the compounds are not available from the authors upon request.

References

  1. Pruthi, J.S. Spices and Condiments: Chemistry, Microbiology, Tecnology; Academic Press: New York, NY, USA, 1980; p. 13. [Google Scholar]
  2. Kollmannsberger, H.; Rodríguez-Burruezo, A.; Siegfried Nitz, S.; Nuez, F. Volatile and capsaicinoid composition of ají (Capsicum baccatum) and rocoto (Capsicum pubescens), two Andean species of chile peppers. J. Sci. Food Agric. 2011, 91, 1598–1611. [Google Scholar] [CrossRef] [PubMed]
  3. Pino, J.; Sauri-Duch, E.; Marbot, R. Changes in volatile compounds of Habanero chile pepper (Capsicum chinense Jack. cv. Habanero) at two ripening stages. Food Chem. 2006, 94, 394–398. [Google Scholar] [CrossRef]
  4. Pino, J.; González, M.; Ceballos, L.; Centurión-Yah, A.R.; Trujillo-Aguirre, J.; Latournerie-Moreno, L.; Sauri-Duch, E. Characterization of total capsaicinoids, colour and volatile compounds of Habanero chilli pepper (Capsicum chinense Jack.) cultivars grown in Yucatan. Food Chem. 2007, 104, 1682–1686. [Google Scholar] [CrossRef]
  5. Pino, J.; Fuentes, V.; Barrios, O. Volatile constituents of Cachucha peppers (Capsicum chinense Jacq.) grown in Cuba. Food Chem. 2011, 125, 860–864. [Google Scholar] [CrossRef]
  6. Murakami, Y.; Iwabuchi, H.; Ohba, Y.; Fukami, H. Analysis of Volatile Compounds from Chili Peppers and Characterization of Habanero (Capsicum chinense) Volatiles. J. Oleo Sci. 2019, 68, 1251–1260. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  7. Cuevas-Glory, L.F.; Sosa-Moguel, O.; Pino, J.; Sauri-Duch, E. GC–MS Characterization of volatile compounds in Habanero pepper (Capsicum chinense Jacq.) by optimization of headspace solid-phase micro-extraction conditions. Food Anal. Methods 2015, 8, 1005–1013. [Google Scholar] [CrossRef]
  8. Sosa-Moguel, O.; Pino, J.A.; Ayora-Talavera, G.; Sauri-Duch, E.; Cuevas-Glory, L. Biological activities of volatile extracts from two varieties of Habanero pepper (Capsicum chinense Jacq.). Int. J. Food Prop. 2017, 20, S3042–S3051. [Google Scholar] [CrossRef] [Green Version]
  9. Ko, A.-Y.; Rahman, M.M.; El-Aty, A.M.A.; Jang, J.; Choi, J.H.; Mamun, M.I.R.; Shim, J.H. Identification of volatile organic compounds generated from healthy and infected powdered chili using solvent-free solid injection coupled with GC/MS: Application to adulteration. Food Chem. 2014, 156, 326–332. [Google Scholar] [CrossRef] [PubMed]
  10. Bogusz, S.J.; Tavares, A.M.; Teixeira Filho, J.; Zini, C.A.; Godoy, H.T. Analysis of the volatile compounds of Brazilian chilli peppers (Capsicum spp.) at two stages of maturity by solid phase micro-extraction and gas chromatography-mass spectrometry. Food Res. Int. 2012, 48, 98–107. [Google Scholar] [CrossRef]
  11. RodrÍguez-Burruezo, A.; Kollmannsberger, H.; González-Mas, M.C.; Nitz, S.; Nuez, F. HS-SPME Comparative Analysis of Genotypic Diversity in the Volatile Fraction and Aroma-Contributing Compounds of Capsicum Fruits from the annuum−chinense−frutescens Complex. J. Agric. Food Chem. 2010, 58, 4388–4400. [Google Scholar] [CrossRef] [PubMed]
  12. Cremer, D.R.; Eichner, K. Formation of volatile compounds during heating of spice paprika (Capsicum annuum) powder. J. Agric. Food Chem. 2000, 48, 2454–2460. [Google Scholar] [CrossRef] [PubMed]
  13. Schreier, P. Chromatographic Studies on Biogenesis of Plant Volatiles; Huthing Verlag: Heidelberg, Germany, 1984. [Google Scholar]
  14. Defilippi, B.G.; Manríquez, D.; Luengwilai, K.; González-Agüero, M. Aroma volatiles: Biosynthesis and mechanisms of modulation during fruit ripening. Adv. Bot. Res. 2009, 50, 1–37. [Google Scholar]
  15. Luning, P.A.; de Rijk, T.; Wichers, H.J.; Roozen, J.P. Gas Chromatography, Mass Spectrometry, and Sniffing Port Analyses of Volatile Compounds of Fresh Bell Peppers (Capsicum annuum) at Different Ripening Stages. J. Agric. Food Chem. 1994, 42, 977–983. [Google Scholar] [CrossRef]
  16. Lewinsohn, E.; Sitrit, Y.; Bar, E.; Azulay, Y.; Ibdah, M.; Meir, A.; Yosef, E.; Zamir, D.; Tadmor, Y. Not just colors—Carotenoid degradation as a link between pigmentation and aroma in tomato and watermelon fruit. Trends Food Sci. Technol. 2005, 16, 407–415. [Google Scholar] [CrossRef]
  17. Zoccali, M.; Giuffrida, D.; Salafia, F.; Rigano, F.; Dugo, P.; Casale, M.; Mondello, L. Apocarotenoids profiling in different Capsicum Species. Food Chem. 2021, 334, 127595. [Google Scholar] [CrossRef]
  18. Caporaso, N.; Paduano, A.; Nicoletti, G.; Sacchi, R. Capsaicinoids, antioxidant activity, and volatile compounds in olive oil flavored with dried chili pepper (Capsicum annuum). Eur. J. Lipid Sci. Technol. 2013, 115, 1434–1442. [Google Scholar] [CrossRef]
  19. Paduano, A.; Caporaso, N.; Santini, A.; Sacchi, R. Microwave and Ultrasound-Assisted Extraction of Capsaicinoids from Chili Peppers (Capsicum annuum L.) in Flavored Olive Oil. J. Food Res. 2014, 3, 51–59. [Google Scholar] [CrossRef] [Green Version]
  20. dos Santos Garruti, D.; de Sousa Mesquita, W.; Magalhães, H.C.; da Silva Araújo, I.M.; de Cassia Alves Pereira, R. Odor-contributing volatile compounds of a new Brazilian tabasco pepper cultivar analyzed by HS-SPME-GC-MS and HS-SPME-GC-O/FID. Food Sci. Technol. 2021, 41, 679–701. [Google Scholar] [CrossRef]
  21. The Good Scent Company. Available online: http://www.thegoodscentscompany.com (accessed on 9 March 2022).
  22. Pherobase. Available online: http://www.pherobase.com (accessed on 9 March 2022).
  23. Van den Dool, H.; Kratz, P.D. A generalization of the retention index system including linear temperature programmed gas-liquid partition chromatography. J. Chromatogr. A 1963, 11, 463–471. [Google Scholar] [CrossRef]
Figure 1. GC-MS analysis of the volatile profile for sample 1 (C. chinense—Naga Morich).
Figure 1. GC-MS analysis of the volatile profile for sample 1 (C. chinense—Naga Morich).
Molecules 27 02355 g001
Figure 2. GC-MS analysis of the volatile profile for sample 14 (C. annuum—Calabrian pepper).
Figure 2. GC-MS analysis of the volatile profile for sample 14 (C. annuum—Calabrian pepper).
Molecules 27 02355 g002
Figure 3. GC-MS analysis of the volatile profile for sample 17 (C. baccatum—Aji).
Figure 3. GC-MS analysis of the volatile profile for sample 17 (C. baccatum—Aji).
Molecules 27 02355 g003
Figure 4. Distribution of volatile compounds’ class identified in the analyzed samples.
Figure 4. Distribution of volatile compounds’ class identified in the analyzed samples.
Molecules 27 02355 g004
Figure 5. PCA analysis based on relative percentage areas of the 118 most abundant identified volatiles in chili peppers (A) and in chili peppers compared with chili-pepper-flavored extra virgin oils (B). X and Y axis show principal component 1 and principal component 2, which explain (A) 30.8% and 25.2% of the total variance and (B) 26.1% and 22.9% of the total variance, respectively. Prediction ellipses are such that with probability of 0.95, a new observation from the same group will fall inside the ellipse. N = 19 data points.
Figure 5. PCA analysis based on relative percentage areas of the 118 most abundant identified volatiles in chili peppers (A) and in chili peppers compared with chili-pepper-flavored extra virgin oils (B). X and Y axis show principal component 1 and principal component 2, which explain (A) 30.8% and 25.2% of the total variance and (B) 26.1% and 22.9% of the total variance, respectively. Prediction ellipses are such that with probability of 0.95, a new observation from the same group will fall inside the ellipse. N = 19 data points.
Molecules 27 02355 g005
Figure 6. Hierarchical cluster analysis based on relative percentage areas of the 118 most abundant identified volatiles. Original values are ln(x + 1)-transformed. Rows are centered; Pareto scaling is applied to rows. Imputation is used for missing value estimation. Columns are clustered using correlation distance and average linkage. There is a total of 44 rows and 20 columns.
Figure 6. Hierarchical cluster analysis based on relative percentage areas of the 118 most abundant identified volatiles. Original values are ln(x + 1)-transformed. Rows are centered; Pareto scaling is applied to rows. Imputation is used for missing value estimation. Columns are clustered using correlation distance and average linkage. There is a total of 44 rows and 20 columns.
Molecules 27 02355 g006
Figure 7. Aroma profile of three different species of pepper chosen as example from descriptive sensory analysis on line scale (n = 10). Panel (A) shows sample 1 (Naga Morich, Capsicum chinense); panel (B) shows sample 14 (Calabrian pepper, Capsicum annuum); and panel (C) shows sample 17 (Aji, Capsicum baccatum).
Figure 7. Aroma profile of three different species of pepper chosen as example from descriptive sensory analysis on line scale (n = 10). Panel (A) shows sample 1 (Naga Morich, Capsicum chinense); panel (B) shows sample 14 (Calabrian pepper, Capsicum annuum); and panel (C) shows sample 17 (Aji, Capsicum baccatum).
Molecules 27 02355 g007
Table 1. Chili peppers samples (1–17) and flavored chili pepper EVOOs (18–20) analyzed.
Table 1. Chili peppers samples (1–17) and flavored chili pepper EVOOs (18–20) analyzed.
SampleChili Pepper TypeSpecieColor
1Naga MorichCapsicum chinenseRed
2Trinidad ScorpionCapsicum chinenseRed
3Habanero FataliiCapsicum chinenseYellow
4Naga YellowCapsicum chinenseYellow
5Naga ChocolateCapsicum chinenseBrown
6Trinidad Scorpio MorugaCapsicum chinenseOrange
7Habanero Red SavinaCapsicum chinenseRed
8Habanero ChocolateCapsicum chinenseBrown
9Scotch BonnetCapsicum chinenseOrange
10Banana PepperCapsicum annuumYellow
11TerenzioCapsicum annuumRed
12Cayenna ImpalaCapsicum annuumRed
13JalapeňoCapsicum annuumRed
14Calabrian pepperCapsicum annuumRed
15EroticCapsicum baccatumOrange
16JimmiCapsicum baccatumOrange
17AjiCapsicum baccatumYellow
Oil SampleChili Pepper typeSpecieColor
EVOO 1MerkénCapsicum baccatumYellow
EVOO 2Mix of peppersCapsicum chinenseYellow
EVOO 3Mix of peppersUnknownOrange
Table 2. Most abundant volatile compounds contained in the chili peppers samples analyzed expressed in area % as GC-FID measurement.
Table 2. Most abundant volatile compounds contained in the chili peppers samples analyzed expressed in area % as GC-FID measurement.
CompoundLRLexLRLlibCapsicum chinenseCapsicum annumCapsicum baccatum
1234567891011121314151617
1(E)-2-Butenal6196290.460.200.450.380.210.320.20.330.780.40.461.191.390.890.500.410.75
23-methyl-2-Butanone6556570.340.201.200.240.300.070.560.420.721.271.221.681.271.650.600.390.61
3Isovaleric aldehyde6576520.180.100.520.100.090.080.200.100.851.801.510.711.070.110.200.131.29
4Acetic acid6596611.020.090.250.770.300.590.391.140.6030.4110.519.2925.979.461.260.972.38
52-Methylbutyraldehyde664662trtr0.07trtr0.140.150.060.132.082.971.640.620.250.370.090.06
6Isopropyl acetate 6606500.06 trtr 0.650.810.120.440.21 0.99
73-Methyl-2-butanol668674trtr 0.08trtr 0.080.120.510.630.520.591.400.81 0.12
8(Z)-2-Buten-1-ol673671trtr trtr 0.180.120.540.190.280.350.560.260.081.231.61
93-Penten-2-one690691trtr0.10trtrtr0.130.080.181.990.240.850.120.13 4.25
10Propionic acid7036980.21 0.070.06 tr 0.740.220.701.860.480.190.350.190.060.23
11Acetoin7267161.400.100.070.270.130.110.090.594.5517.536.1611.8813.883.650.42 0.55
12Isoprenol729724trtr0.06trtr0.11trtr0.201.353.130.440.220.050.180.230.25
13Isopentyl alcohol7337290.09trtrtrtr0.051.060.790.251.301.251.120.830.320.29 1.95
14sec-Butylcarbinol738733trtrtrtr 0.070.650.150.190.950.851.181.780.33 0.11
16Isopropyl ethyl ketone745742trtr0.060.07trtr0.140.11 1.16 0.230.26 0.07
17Ethyl isobutanoate754754trtr0.06trtr0.10.200.50.440.292.081.400.140.320.320.120.18
18Isobutyric acid761774trtrtrtrtr 0.110.050.521.110.160.720.060.05 0.12tr
19Toluene764763 tr 0.24 0.380.540.20tr1.70 0.37
20Pentyl alcohol7637630.07trtrtrtr0.181.440.740.260.160.280.390.150.840.200.170.26
21(E)-2-Penten-1-ol7667610.12tr0.06tr 1.030.360.210.610.530.350.28 0.32tr
22Prenol770772trtrtrtrtr0.07 0.390.270.300.300.300.160.060.330.160.72
232,3-Butadienol7887880.10 trtrtr 0.220.410.050.260.650.180.341.630.060.48
243-Methylcrotonaldehyde787780 trtrtrtr 0.200.11tr0.620.21 0.05
25Isopentyl formate788791 trtrtr 0.38 0.230.28 0.60
27(Z)-3-Hexenal798797 trtr trtr0.451.460.120.230.630.39
28n-Hexanal801801trtr0.06trtrtrtr0.850.792.152.352.253.443.7416.2620.7416.38
292-Hexanol8068021.43 trtrtr0.750.500.291.321.630.19 4.47 0.27
30Ethyl lactate806814 trtr 0.220.210.470.120.390.20 0.980.711.37
314-Methyl-2-pentenal816814 trtrtrtrtr 0.530.110.370.320.651.322.751.462.04
334-Methyl-1-pentanol8388322.720.440.670.400.511.3723.1513.612.482.032.721.411.590.520.210.190.35
35Ethyl 2-methylbutanoate8468420.06tr0.130.11tr0.112.860.790.490.40.360.160.230.27 0.14
37(E)-2-Hexenal850850 tr 0.090.6119.380.598.0529.82.466.5726.8543.2234.5921.58
38(E)-3-Hexenol8548470.500.530.250.500.490.556.070.68 0.33 0.150.888.99 3.36
39(Z)-3-Hexenol8568560.320.310.15tr0.21 2.110.54 0.36
40Isovaleric acid8388420.110.110.18tr0.050.380.630.410.210.610.870.201.010.77
41(E)-2-Hexenol8648640.09 0.07trtr 0.362.80 1.042.890.193.082.911.071.581.90
42n-Hexanol8688670.370.740.120.30.570.252.921.890.260.912.740.421.453.227.533.632.44
432-Methylbutyric acid883881trtrtrtrtrtr0.270.070.11 0.220.650.63tr0.460.14
44n-Pentanoic acid889918trtrtrtrtrtr0.10 0.090.200.600.230.440.12tr tr
603-Methyl-ethylpentanoate962953trtrtrtrtrtr0.64 0.860.06trtr0.10tr 0.25tr
696-Methyl-hept-5-en-2-one984986trtr0.06trtr0.07tr0.060.520.480.210.310.57 0.110.180.46
70n-Hexanoic acid989997trtr0.10trtrtr0.070.070.710.340.140.240.670.420.510.360.08
71Ethyl hexanoate9981003trtr0.120.06trtrtr0.58 0.68 0.08trtr0.350.890.52
80p-Cymene10251024trtrtrtrtrtrtr0.330.60.070.150.120.06trtr0.330.05
81Limonene10281030tr0.06trtrtrtr0.070.311.050.060.220.550.41tr0.080.180.43
84(Z-β-Ocimene10351035tr tr trtrtr0.23trtrtrtrtrtr 0.64
90(E)-β-Ocimene10461046 tr tr 0.170.050.970.960.30.320.24 2.55 9.70
91Isopentyl butanoate10481050 trtr0.05trtr0.140.30.05 tr 1.080.060.050.060.06
94(E)-2-Octenal10671058trtrtrtrtrtr 0.720.090.170.060.110.07tr0.060.07tr
98Guaiacol10861094tr trtrtrtrtr0.130.70trtr 0.07tr0.100.380.52
99Isobutyl tiglate10911093trtrtrtrtrtr0.08tr0.200.12tr1.130.20tr0.190.340.64
1003-Methylbutyl 2-methylbutanoate10981104trtrtrtrtr0.22tr0.19 0.10 0.13tr 0.09tr0.54
101Linalool10981101 trtrtrtr 0.300.830.170.060.080.19tr
103n-Nonanal11031107tr trtrtr trtr0.470.110.181.330.250.25 0.210.75
1043-Methylbutyl isovalerate110411090.260.070.290.290.090.920.250.350.860.270.29 0.67
1052-Methylbutyl isovalerate11061109tr trtrtr0.15tr0.65 tr 0.09tr0.11 trtr
1063-Methylpentyl isobutanoate111011150.15tr0.290.150.060.322.080.050.210.060.060.700.57trtr0.47tr
107Isohexyl isobutanoate11121110tr0.75trtrtrtrtr0.090.79tr0.220.120.14tr0.07trtr
111(4E,6Z)-Alloocimene11281128tr tr trtr 0.07 0.070.09tr0.13tr0.90
1122-Vinylanisole11301135 trtrtr0.08trtr 0.09 0.15 0.87
114(E,E)-Allocimene11401145 tr 0.11 0.05 0.06tr0.210.081.33
116Pentyl isovalerate114211430.340.180.230.640.081.080.210.270.07tr 0.10 tr
117Hexyl isobutanoate11461150tr0.540.130.130.060.120.250.050.14tr0.060.14 tr tr
1253-Methoxy-2-isobutylpyrazine11751176 tr0.060.520.19tr1.740.07trtr0.50
1344-Methylpentyl 2-methylbutanoate119812026.543.142.412.331.089.8013.2112.864.581.311.401.231.122.950.050.130.31
1354-Methylpentyl 3-methylbutanoate1209120633.1221.1116.0221.6713.9832.822.6916.6520.132.321.442.211.421.520.620.761.16
138Citronellol122212320.11 tr0.071.99trtr0.110.07trtrtrtrtrtr tr
140ESTER1229 0.781.190.550.640.740.250.321.170.120.07tr0.11trtrtrtr0.16
141(Z)-3-Hexenyl 2-methylbutanoate123312312.414.792.361.342.021.591.640.890.48tr0.050.200.05trtrtrtr
142(Z)-3-Hexenyl 3-methylbutanoate123712431.022.921.427.741.509.550.960.570.65tr0.050.170.11trtr0.050.31
143Hexyl 3-methylbutanoate124612434.027.884.5712.348.877.770.160.090.17trtr0.10trtrtr0.12tr
144(E)-Hex-2-enyl 3-methylbutanoate124812430.370.450.180.320.961.14trtr0.06 tr0.12tr0.21trtrtr
145Heptyl isobutanoate12511248tr0.800.210.17tr0.07trtrtr tr0.09trtrtr tr
1516-Methylhept-4-en-1-yl isobutanoate128912930.151.390.790.090.990.050.05tr0.09trtr0.08 tr tr
1523-Methylpentyl (2E)-2-methyl-2-butenoate129113000.50.390.170.390.20.470.141.770.22 0.09trtrtr 0.05
1555-Methylhexyl 3-methylbutanoate130013030.14 0.210.35 tr0.060.821.861.090.542.390.310.620.080.190.20
157ESTER1302 0.170.230.070.13 0.170.110.66 tr tr
158Heptyl butanoate130812980.180.240.411.160.310.150.100.12 tr tr
1594-Methylhexyl 2-methylbutanoate130813070.870.620.330.120.120.440.380.270.120.06 0.110.10tr 0.05
1604-Methylpentyl 4-methylpentanoate131313151.631.091.020.640.760.460.600.530.27tr0.070.08tr2.02trtrtr
165Heptyl 2-methylbutanoate133213330.311.450.590.660.910.14trtr0.29tr trtr tr
167Heptyl isovalerate133813381.674.973.384.095.500.460.130.08 trtr0.26trtrtr0.050.11
170α-Cubebene134713470.680.31tr0.690.480.210.06 0.09trtr0.08tr tr0.07
171ESTER1352 0.240.750.30.390.570.120.1tr0.09 tr0.07tr tr
172α-Longipinene135413520.080.060.34 0.35tr0.05tr1.57 tr 0.091.01 tr
1742-Methyl tridecane136213651.540.210.190.310.160.160.050.071.260.050.210.530.333.28tr0.28tr
176α-Ylangene137213710.09trtrtr1.430.07tr- tr0.06 trtr tr
177Cyclosativene13701367 trtr tr0.050.580.06tr0.17tr tr tr
178α-Copaene13761375tr0.73tr0.73 0.060.080.27 0.180.341.830.560.65tr0.360.09
1796-Methylhept-4-en-1-yl 2-methylbutanoate137813831.721.612.021.4516.30.440.050.0910.37 1.840.07 0.56tr
1806-Methylhept-4-en-1-yl 3-methylbutanoate138513887.7714.1211.6714.4516.151.130.81tr0.34 0.050.191.76trtrtr0.22
181β-Elemene138913900.22tr0.09 0.08tr 0.59tr0.310.290.190.380.289.36tr
182Sativene13921394 trtrtr0.220.07tr0.130.61 tr
1836-Methylheptyl 2-methylbutanoate139413980.430.770.640.360.570.24trtr trtrtr 0.16
1866-Methylheptyl 3-methylbutanoate139914021.531.752.101.153.16trtr-0.13 trtr0.06trtr
192(E)-α-Ionone14211421 0.11 0.300.240.13trtr tr0.09 tr0.520.96
196(E)-α-Bergamotene14351432tr 0.20trtrtr tr 1.120.07 tr
1976-Methyl-4-heptenyl pentanoate143614380.090.550.500.601.210.09tr0.16 tr tr
198Octyl isovalerate143714410.310.810.580.581.55trtr- trtrtr tr
199ESTER1443 4.191.830.841.100.680.740.110.161.57tr0.200.260.140.51tr0.13tr
200(E)-Geranylacetone144614500.100.230.160.060.23 trtr0.74trtr0.110.08trtr0.100.27
202α-Himachalene145014490.120.100.83tr0.26 0.45 0.17 0.23
2062-Methyl tetradecane146214631.110.671.080.770.050.420.070.221.390.090.210.270.111.04tr0.14tr
207Oxacyclododecan-2-one1467 0.440.240.932.780.050.09trtr 0.16tr0.08 0.090.06
210(E)-β-Ionone148214820.350.740.150.240.140.400.090.06 trtr0.090.180.21tr0.17tr
211γ-Himachalene148314810.350.994.740.270.6011.64tr1.071.84trtr0.09trtrtr tr
212β-Chamigrene148414790.41trtr0.050.130.30tr0.200.570.06tr0.970.111.40tr0.60
2136-Methylhept-4-en-1-yl 2-methylbutanoate147814810.18 0.32tr2.08 0.26tr0.220.14 0.07
214Isobutyl 8-methylnon-6-enoate148814960.330.713.360.350.250.10trtr0.09 tr0.24trtrtr0.860.05
217α-Selinene149615010.140.50trtr0.270.06trtr tr 0.78
218n-Pentadecane149815000.540.860.570.390.060.380.060.090.530.060.130.23tr0.05tr 0.07
219α-Cuprenene150115080.08tr0.180.110.100.57tr0.210.280.210.150.060.320.310.130.28tr
220Isobutyl 8-methylnonanoate 150214960.070.080.39trtrtr0.10tr1.18 0.74tr0.10 tr0.11
223δ-Cadinene151915180.760.590.220.540.300.19trtr0.06 tr0.10trtrtr0.11tr
2272-Methylbutyl 8-methylnon-6-enoate153715452.144.026.351.190.420.31trtr trtr0.11tr0.25 tr
235Dendrolasin157015730.240.280.060.55trtr 0.14 tr0.39tr0.09
237(E)-2-Tridecen-1-ol158315730.160.150.530.100.16trtr tr
238Isopentyl 8-methylnon-6-enoate158615920.360.270.890.260.96trtrtr0.15 tr0.06tr0.80trtrtr
249Cadalene167516770.12trtrtr0.05trtrtr tr0.16tr1.40trtrtr
2504-Methylpentyl 8-methylnon-6-enoate168516920.350.282.220.180.150.09trtr0.26 tr0.19 tr
2524-Methylpentyl 8-methylnonanoate170217100.090.070.630.080.050.06tr0.070.08 tr0.160.07trtr tr
261ESTER1852 trtr0.82trtrtr
Total 91.7291.4784.2188.8892.4490.9191.194.3482.0489.7389.3580.5387.9790.892.0492.1785.31
The compound’s number is reported in order of elution, considering the total number of compounds eluted. For the identification of the compounds not reported in this table, see Table S1 from Supplementary Materials. tr = trace compound.
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Trovato, E.; Vento, F.; Creti, D.; Dugo, P.; Mondello, L. Elucidation of Analytical–Compositional Fingerprinting of Three Different Species of Chili Pepper by Using Headspace Solid-Phase Microextraction Coupled with Gas Chromatography–Mass Spectrometry Analysis, and Sensory Profile Evaluation. Molecules 2022, 27, 2355. https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27072355

AMA Style

Trovato E, Vento F, Creti D, Dugo P, Mondello L. Elucidation of Analytical–Compositional Fingerprinting of Three Different Species of Chili Pepper by Using Headspace Solid-Phase Microextraction Coupled with Gas Chromatography–Mass Spectrometry Analysis, and Sensory Profile Evaluation. Molecules. 2022; 27(7):2355. https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27072355

Chicago/Turabian Style

Trovato, Emanuela, Federica Vento, Donato Creti, Paola Dugo, and Luigi Mondello. 2022. "Elucidation of Analytical–Compositional Fingerprinting of Three Different Species of Chili Pepper by Using Headspace Solid-Phase Microextraction Coupled with Gas Chromatography–Mass Spectrometry Analysis, and Sensory Profile Evaluation" Molecules 27, no. 7: 2355. https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27072355

Article Metrics

Back to TopTop