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Article

Analysis and Comparison of Aroma Compounds of Brown Sugar in Guangdong, Guangxi and Yunnan Using GC-O-MS

by
Erbao Chen
1,
Shuna Zhao
1,2,*,†,
Huanlu Song
1,*,†,
Yu Zhang
1 and
Wanyao Lu
2,3
1
Beijing Engineering and Technology Research Center of Food Additives, School of Food and Health, Beijing Technology and Business University, Beijing 100048, China
2
Beijing Engineering Laboratory of Geriatric Nutrition & Foods, COFCO Nutrition and Health Research Institute Co., Ltd., Beijing 102209, China
3
COFCO Sugar Co., Ltd., Key Laboratory of Quality & Safety Control for Sugar Crops and Tomato, Ministry of Agriculture of the PRC, Changji 831100, China
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Molecules 2022, 27(18), 5878; https://doi.org/10.3390/molecules27185878
Submission received: 15 August 2022 / Revised: 31 August 2022 / Accepted: 1 September 2022 / Published: 10 September 2022
(This article belongs to the Special Issue Recent Advances of Spectrometric and Spectroscopic Techniques in Food Quality and Safety)
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Abstract

:
Guangdong, Guangxi and Yunnan are the three provinces in China that yield the most brown sugar, a brown-red colored solid or powdered sugar product made from sugar cane. In the present study, the differences between odor compounds of brown sugar from Guangdong, Guangxi, and Yunnan provinces in China were compared and analyzed by gas chromatography-olfactometry-mass spectrometry (GC-O-MS). A total of 80 odor compounds, including 5 alcohols, 9 aldehydes, 8 phenols, 21 acids, 14 ketones, 5 esters, 12 pyrazines, and 6 other compounds, were detected. The fingerprint analysis of the brown sugar odor compounds showed 90% similarity, indicating a close relationship among the odor properties of brown sugar in each province. Moreover, the orthogonal partial least squares discriminant analysis (OPLS-DA) was performed to identify the compounds contributing to the volatile classification of the brown sugar from three provinces, which confirmed that OPLS-DA could be a potential tool to distinguish the brown sugar of three origins.

1. Introduction

Brown sugar, a traditional sweetener with a distinctive flavor, is mainly made from sugarcane through extraction, clarification, and boiling [1]. It is also called non-centrifugal cane sugar (NCS), which does not separate molasses, so it retains the original flavor and nutrients of sugarcane. Brown sugar is rich in flavonoids and phenols that may act as antioxidants and, therefore, exert benefits on organisms [2,3,4]. Furthermore, it exerts immunomodulatory, cytoprotective, anti-carcinogenic, and anti-cancer properties [5].
A study on the physicochemical properties and storage stability of brown sugar revealed darker color, increased water content and water activity, but decreased glucose and fructose contents due to the Maillard reaction [6]. Similarly, a study on the odor components of brown sugar revealed that acetaldehyde, 2-methylbutyraldehyde, 3-methylbutyraldehyde, 2,6-dimethylpyrazine, nonanal, 2,6-diethylpyrazine, 2,3,5-trimethylpyrazine, furfural, 2,3-dimethylpyrazine, decanal, and 2-acetylpyrrole were the primary components based on their relative concentration [7]. Juliana et al. [8] extracted a total of six odor compounds from brown sugar beverages through simultaneous steam distillation-solvent extraction using a mixture of diethyl ether-pentane (1:1, w/w) as the solvent. Of the six components, 2-methylpyrazine was the key aroma compound in this beverage. Our previous research has proved that heating of syrup was the primary production step affecting the brown sugar flavor because of the production of a large number of pyrazine compounds [9].
Brown sugar has a green and a strong caramel aroma. Some aroma compounds are inherent in sugarcane, while others are produced by microbial metabolism and Maillard reaction. Sugarcane varieties, growing regions, processing methods, storage conditions and other factors will affect the flavor of brown sugar [10]. The composition and concentration of odor compounds and nutrients in sugarcane from different producing areas are different, which leads to great differences in the flavor composition of brown sugar. However, it is difficult to distinguish the origin of brown sugars only by sensory evaluation. As an intuitive and reproducible method, GC-MS analysis has been effectively applied in origin differentiation studies [11]. Li et al. [12] and Zhao et al. [13] used GC-MS to analyze the volatile odor compounds of ham and rice, respectively, and the results proved that GC-MS played an important role in food odor analysis and origin identification.
Previous studies on brown sugar mostly focused on the identification of key aroma, and there is no study on the flavor differences of brown sugar in different regions. Guangdong, Guangxi and Yunnan are the three major producing areas of brown sugar in China. To the best of our knowledge, the discrimination of brown sugar according to origin has not been reported previously. Therefore, the purpose of this study is to (1) identify the odor compounds of the 18 brown sugar samples from Guangdong, Guangxi, and Yunnan using LLE/GC-O-MS; (2) determine the key odor compounds in brown sugar by calculating OAV; (3) establish the fingerprints of brown sugar from three different origins and (4) find out the compounds that cause the difference using OPLS, so as to provide the basis for selecting brown sugar from different regions when producing foods with different flavor characteristics.

2. Results and Discussion

2.1. Volatile Aroma Components Analysis

A total of 80 odor compounds, including 5 alcohols, 9 aldehydes, 8 phenols, 21 acids, 14 ketones, 5 esters, 12 pyrazines, and 6 other compounds, were detected in 18 samples from three different regions (Table 1). The brown sugar samples from Guangdong, Guangxi and Yunnan contained 72, 60 and 75 odor compounds, respectively. There are four kinds of alcohols in all three regions, but the types of acid compounds are quite different, with Guangdong and Yunnan containing 20 and 19 acid compounds, respectively, while Guangxi contained only 12 acid compounds. The types of pyrazines, aldehydes, ketones and phenols in the three regions are very close. By comparing the odor compounds in the three regions, it was found that the unique odor compounds of the brown sugar samples in Guangdong were 2-acetyl-5-methylpyrazine, 2-methylbutanoic acid and 3-phenylpropionic acid; the unique odor compound in Guangxi was propylene glycol; and the unique odor compounds in Yunnan were 1,3-dimethoxy-2-hydroxybenzene, 3-hydroxyl-2-methyl-4H-pyran-4-one, 3-methyl-1,2-cyclopentanedione, 4-methylpentanoic acid and γ-butyrolactone. These unique odor compounds are expected to be important indicators to distinguish the origin of brown sugar samples.
The average contents of odor compounds in brown sugar samples from the three regions are shown in Figure 1. It can be seen that the highest contents of acid compounds were found in all three regions with 25,595.06, 21,632.44 and 25,187.12 ng/g, followed by phenolic compounds with average contents of 111,69.29, 12,115.37 and 11,744.16 ng/g. In contrast, alcohols, esters, pyrazines and ketones had lower contents.

2.2. Analysis of Key Aroma Compounds in Brown Sugar Samples

A total of 46 aroma-active compounds were identified in 18 brown sugar samples by olfactometry, including 4 alcohols, 4 aldehydes, 3 phenols, 15 acids, 11 ketones, 7 pyrazines, and 2 other compounds. According to the odor properties of the aroma active compounds, these compounds can be classified into nine types: sweet/caramel, fruity, green/grassy, sour, sweaty/cheese, nutty, roasted, fatty and potato, which indicated that the aroma profile of brown sugar was the result of the synergistic effect of various odors.
In fact, it is the OAV of the aroma compound, and not its amount, that determines the contribution of the aroma compound. Aroma activity is generally defined as compounds with OAVs greater than 1 [14]. Therefore, the calculation of OAV was carried out for aroma compounds that can be sniffed (Table 2). Among the 18 brown sugar samples, 26 compounds with OAV >1 were considered as the key aroma active compounds of the brown sugar samples in this study and contributed to the overall flavor.
Alcohols: Among the four alcohols that can be sniffed, only furfuryl alcohol had OAV >1 and was only found in Guangxi and Yunnan. The content of furfuryl alcohol in Guangxi and Yunnan was 971.50 and 392.70 ng/g, respectively, and it contributed sweet, toast and caramel aroma to brown sugar. Sugar and amino acids react readily at elevated temperatures to form this compound [15]. The furfuryl alcohol contained in soy sauce has been considered to be one of the main components responsible for its odor, exhibiting a caramel scent, which contributes to the overall flavor of the sample [16].
Aldehydes: Among the aldehydes, there are four aldehydes with OAV >1, namely hexanal, (E)-2-nonenal, 3,5-dimethoxy-4-hydroxybenzaldehyde and benzaldehyde. (E)-2-nonenal and hexanal are probably oxidation products of polyunsaturated fatty acids [17], with high OAV due to their higher concentration and lower odor threshold, and are key aroma compounds among aldehydes, contributing to the green odor of brown sugar. The average content of benzaldehyde in Guangdong was higher than that in Guangxi and Yunnan, and it may be the degradation product of phenylalanine [14], contributing nutty and caramel aromas to the brown sugar. 3,5-dimethoxy-4-hydroxybenzaldehyde showed close OAV in Guangdong and Yunnan, and was higher than that in Guangxi, contributing sweet and nutty aroma to brown sugars. According to Chen, Song, Li, Chen, Wang, Che, Zhang and Zhao [9], 3,5-dimethoxy-4-hydroxybenzaldehyde is formed during brown sugar production, and the difference in content might be related to the raw materials and processing technology.
Ketones: Four ketones with OAV >1 were found in brown sugar samples, including 3-methyl-1,2-cyclopentanedione, 2-hydroxy-3-methyl-2-cyclopenten-1-one, 2,5-dimethyl-4-hydroxy-3(2H)-furanone, and 4-hydroxy-5-methyl-3(2H)-furanone. 2,5-Dimethyl-4-hydroxy-3(2H)-furanone has the highest OAV and contributes a strong caramel flavor to brown sugar, which is most likely formed by the Maillard reaction through deoxy sugars and is most abundant in strawberries [18,19]. 2-Hydroxy-3-methyl-2-cyclopenten-1-one has a strong caramel aroma and is one of the key odor compounds that contribute to the caramel odor in black tea, soy sauce and molasses [20,21,22]. 3-Methyl-1,2-cyclopentanedione was detected only in Yunnan brown sugar with OAV=14, which contributed sweet and bready aroma to Yunnan brown sugar. 2,5-Dimethyl-4-hydroxy-3(2H)-furanone was detected in all the three regions’ samples, but the OAV was greater than 1 only in Guangxi brown sugar, which was caused by its high concentration in Guangxi brown sugar.
Pyrazines: Many products possess a distinctive aroma resulting from pyrazines, which are special Maillard reaction compounds [23,24]. Pyrazine is formed by condensing two α-aminocarbonyl compounds and forming a dihydropyrazine, which oxidizes spontaneously to form the pyrazine [23,25,26]. Among the twelve pyrazines detected in the eighteen samples, there are five kinds of pyrazines with OAV greater than 1, namely 2,3,5-trimethylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethyyl-3-ethylpyrazine, 2,6-dimethyl-3-ethylpyrazine and 2-acetyl-6-methylpyrazine. 2,6-Dimethyl-3-ethylpyrazine exhibited the highest OVA due to its low threshold (OT=0.04 ng/g), contributing a strong roasted potato flavor to brown sugar. 2,5-Dimethylpyrazine and 2,6-dimethylpyrazine were previously reported to be key odor compounds in coffee, exhibiting strong roasted and nutty aroma [27].
Acids: A total of 21 kinds of acid compounds were detected in 18 brown sugars, among which the OAV of 11 kinds of acid compounds was greater than 1. Acetic acid, one of the most abundant compounds in brown sugar, had the highest OAV and contributed sour aroma to the samples. 2-Methylbutanoic acid and 3-methylbutanoic acid exhibited a sour aroma and had been reported to be the key aroma components in Japanese sweet rice wine, which played an important role in the overall flavor of sweet rice wine [28]. Benzoic acid, however, has an unpleasant urine-like odor, which may be caused by phenylalanine under the action of phenylalanine ammonia-lyase in plants [29].

2.3. Fingerprint Analysis of Sugar Products from Three Different Regions

A food fingerprint can be defined as molecular markers that indicate a characteristic state or condition of food, thus enabling more accurate product identification [30]. Each sample is regarded as a multidimensional space vector. If two samples are more similar, their space will be closer, and the angle between the two samples’ space vectors will be smaller, which leads the cosine of the angle between the two vectors to move closer to 1. Therefore, the similarity of samples can be expressed by the cosine of the included angle. On the contrary, if the difference between the two samples is greater, the cosine of the included angle becomes smaller. In this study, the samples were determined by GC-O-MS, and the odor-active compounds were selected for fingerprint and similarity evaluation.
It is worth mentioning that the similarity of samples becomes higher when the similarity or the cosine of the angle is above 90%. As depicted in Table 3 and Figure 2, of the six samples in Guangdong, except for Guangdong3, the similarity and cosine of the included angle of the other five samples were above 90%. This indicated that the odor properties of Guangdong3 were quite different than the other five samples, which might have happened due to different processing technology.
The cosine of the included angle of six samples in Guangxi was above 90%, and the similarity of Guangxi3 was just less than 90% (89.80%). This result indicated that the odor properties of these six samples in Guangxi were similar, without much difference
Of the six samples in Yunnan, only Yunnan2 had similarity and cosine of included angle lower than 90%, while the other five samples had similarity and cosine of included angle higher than 90%. This result indicated that the odor attributes of the other five samples were similar, but Yunnan2 had significant differences with them.

2.4. Verification of Fingerprint

In order to verify whether the fingerprint method is suitable for the analysis of brown sugar, the verification was carried out. Fingerprint verification includes three parts: stability experiment, precision experiment, and repeatability experiment. Following the sample preparation described in Section 2.4, a brown sugar sample was selected and analyzed by GC-MS after 0, 2, 4, 8, 16, and 24 h. Furthermore, the relative standard deviations (RSD) of the relative retention times (RT) and relative peak areas of the odor-active compounds were calculated. The results showed that the RSD of the relative RT of the odor-active compounds was less than 0.3%, and the RSD of the relative peak areas was less than 5%, indicating that the samples were stable within 24 h and met the requirements of the fingerprint method.
A brown sugar sample was extracted and concentrated with the organic solvent, and then the concentration was injected six times consecutively to calculate the RSD of relative RT and relative peak area of the odor-active compounds. These results showed that the RSD of the relative RT of the odor active compounds was less than 0.5%, and the RSD of the relative peak area was less than 6%, indicating that the precision of the instrument was good and met the requirements of the fingerprint method.
Five brown sugar samples were extracted and analyzed for their odor compounds, followed by the RSD of relative RT and relative peak area of the odor active compounds analysis. The results showed that the RSD of relative RT was less than 0.3%, and the RSD of the relative peak area was less than 7%, indicating that they had good repeatability and met the requirements of the fingerprint method.

2.5. Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA)

The fingerprinting analysis of samples from the three origins of Guangdong, Guangxi, and Yunnan revealed that the majority of samples within each province had similar odor types. In addition, a supervised OPLS-DA multivariate statistical analysis method was used to establish a statistical model in order to distinguish odor compounds between Guangdong and Guangxi, Guangdong and Yunnan, and Guangxi and Yunnan.
By conducting OPLS-DA analysis on the brown sugar, a variable importance of projection diagram (VIP) of the model was obtained. A VIP is a vector that summarizes the contribution of a variable to the explanation of the model. Variables with a VIP >1 are generally considered to contribute to the explanation of the model [31,32]. The samples were assessed as independent variables, and the OPLS-DA model was fitted automatically.
The OPLS-DA and VIP results (Figure 3) indicate that the brown sugars from Guangdong and Guangxi were well separated. The brown sugar from Guangdong and Guangxi showed the greatest degree of separation and low intra-group differences, facilitating an accurate exploration of the differences in composition. VIP diagram elucidated that 4-hydroxybenzaldehyde, 3,5-dimethoxy-4-hydroxybenzaldehyde, n-hexadecanoic acid, butanoic acid, acetic acid, 2-methoxy-4-acetylphenol, 2-acetylpyrrole, pentadecanoic acid, furfuryl alcohol, 4-hydroxyacetophenone, etc., were the main contributors to the distinction between Guangdong and Guangxi samples. These compounds were basically aldehydes, acids, ketones, and phenols. Among these, 3,5-dimethoxy-4-hydroxybenzaldehyde and 4-hydroxybenzaldehyde played an important role in classifying Guangdong and Guangxi. 4-Hydroxybenzaldehyde and 3,5-dimethoxy-4-hydroxybenzaldehyde presented a pleasant nutty and creamy odor. Previously, 4-hydroxybenzaldehyde and 3,5-dimethoxy-4-hydroxybenzaldehyde were identified as the major volatile constituents in brown sugars [33]. Acetic acid is also one of the key compounds that can distinguish brown sugar from two provinces. Acetate is a well-known product of the thermal degradation of saccharides, and it is primarily formed during the early stage of the Maillard reaction, under neutral and alkaline conditions. Acetic acid is formed exclusively by hydrolytic cleavage of β-dicarbonyl in hexose-based systems [34].
As shown in Figure 4, OPLS-DA analysis and VIP results indicate that the brown sugars from Guangdong and Yunnan are distinguishable. The principal compounds contributing to this distinction include n-hexadecanoic acid, acetic acid, dibutylphthalate, 2-acetylpyrrole, 2,5-dimethylpyrazine, and 2-methylpyrazine. Of the compounds with VIP greater than 1, pyrazine compounds appeared, which indicated that pyrazine compounds played a significant role in distinguishing brown sugar between Guangdong and Yunnan. The average content of pyrazines in Guangdong and Yunnan was 2897.28 ng/g and 1441.20 ng/g, respectively, and the pyrazine contents in Guangdong samples were higher than in Yunnan. These compounds could impart a popcorn, nutty, and roasted aroma to brown sugar.
Based on the VIP diagram and OPLS-DA analysis of brown sugar between Guangxi and Yunnan (Figure 5), they were well separated. A number of compounds contributed to the differentiation between the two provinces, including 4-hydroxybenzaldehyde, 3,5-dimethoxy-4-hydroxybenzaldehyde, n-hexadecanoic acid, acetic acid, butanoic acid, and 4-hydroxyacetophenone. Of these volatile compounds, the contribution of 4-hydroxybenzaldehyde was the greatest. The average content of 4-hydroxybenzaldehyde in Guangxi was 2728.55 ng/g, while the samples from Guangxi had no odor compounds. The average contents of 3,5-dimethoxy-4-hydroxybenzaldehyde in Guangxi and Yunnan were 926.34 ng/g and 2967.95 ng/g and the contents in Yunnan were significantly higher than in Guangxi. Perhaps these compounds play an important role in distinguishing the sugars from Guangxi and Yunnan.

3. Materials and Methods

3.1. Materials

Eighteen brown sugar samples from Guangdong, Guangxi and Yunnan were provided by COFCO. These samples were stored in a refrigerator at −80 °C before analysis.

3.2. Standards and Reagents

Ether (purity > 99%), dichloromethane (purity > 99%), anhydrous sodium sulfate, 2-methyl-3-heptanone (purity > 99%) and n-alkane (C7-C30) were purchased from Sigma-Aldrich (St. Louis, MO, USA), and carrier gas (helium) was purchased from Beijing AP Baif Gases Industry Co., Ltd. (Beijing, China).

3.3. Extraction of Odor Compounds from Sugars

The odor compounds in brown sugar were extracted by a liquid–liquid extraction (LLE) method according to Chen et al. [33]. In brief, 50.00 g of brown sugar was placed in a triangular flask, 50 mL of distilled water was added to dissolve the brown sugar, then, 50 mL of ether, 50 mL of dichloromethane and 5 μL of internal standard 2-methyl-3-heptanone (81.6 mg/mL) were added, and the mixture was magnetically stirred at 1000 rpm for 10 min. After centrifugation (Hitachi, Japan) for 30 min at 10,000 rpm, the extract containing the volatile aroma compounds was separated by a funnel. Subsequently, 150.0 g anhydrous sodium sulfate was added to the extract and put into a refrigerator at 4 °C to remove water for 12 h, and filtered with a filter paper. A gentle nitrogen stream was used to concentrate the volume into 100 μL, and the odor compounds were extracted and stored at −80 °C for further analysis.

3.4. GC-O-MS

Three well-trained panelists conducted a GC-O analysis of the concentrated distillate. The panelists were recruited from Beijing Technology and Business University’s Molecular Sensory Laboratory. To identify and describe the aroma characteristics of the reference compounds, they smelled several concentrations of reference compounds in model solutions 2 h per day before analysis. The training lasted for one month. For the GC-O analysis, wet gas was delivered to the nose using a blank capillary column to improve the sensitivity of the panelists. The aroma perceptions, intensity, and RT were recorded by the panelists. If two or more panelists detected the aroma, an aroma-active compound was identified [35].
To determine the volatile aroma profile of sugars, an Agilent 7890A gas chromatograph (GC) coupled with an Agilent 5977B mass spectrometer (MS) and a sniffing port (Gerstel, Germany) was used. The aroma extract (1 μL) was injected into a DB-Wax column (60 m × 0.25 mm i.d., film thickness 0.25 μm, Agilent J&W) through splitless mode, and the flow rate of the helium carrier gas was maintained at 1.7 mL/min. The oven temperature was initially programmed at 40 °C, further raised to 100 °C at a rate of 4 °C/min, following a gradual increase up to 200 °C at a rate of 3 °C/min for 5 min, and after achieving an ultimate temperature of 230 °C at a rate of 3 °C/min, it was maintained for 10 min. The interface and ion source were set at 250 °C and 230 °C, respectively, while the electron-impact ionization was set at 70 eV, the acquisition range (m/z) at 35–350 amu, and the scan rate at 1.77 scans/s. The transmission line temperature of the olfactory detection port (ODP) was maintained at 235 °C.

3.5. Qualitative Analysis

The ionization of a molecule in a vacuum produces a characteristic group of ions of different masses. The plot of relative abundance versus mass of these ions constitutes a mass spectrum. The spectrum can be used to identify the molecule. The unknowns were identified by comparing the fragments with the National Institute of Standards and Technology (NIST) MS Spectral Library (Version 2020), by comparing the odor percepts with the database (http://www.thegoodscentscompany.com) and by calculating the linear retention indices (LRIs) using a homologous series of n-alkanes (C7-C30). The use of multiple methods can increase the accuracy of qualitative results. Using the internal standard area, the resulting peaks were calibrated, and the aroma compound contents were expressed as nanograms per gram of sample [10].

3.6. Odor Activity Value (OAV)

In order to evaluate the contribution of each odorant to the overall aroma of brown sugar, the OAV (ratio of concentration to its odor threshold) was calculated [36]. These threshold values were derived from the literature in water [37].

3.7. Statistical Analysis

All experiments in this study were conducted in triplicates, and the data were expressed as mean ± standard deviation. The bar graph was drawn by OriginPro 2022 (OriginLab Corp., Northampton, MA, USA), the OPLS-DA analysis was conducted by SIMCA 14.1 (MKS Instruments, Andover, MA, USA), and the tables were organized by Microsoft Excel 2021 (Microsoft Corp., Redmond, WA, USA).

4. Conclusions

In summary, a total of 80 odor compounds, including 5 alcohols, 9 aldehydes, 8 phenols, 21 acids, 14 ketones, 5 esters, 12 pyrazines, and 6 other compounds, were detected in 18 brown sugar samples from three different provinces. The fingerprint analysis showed 90% similarity, indicating a close relationship among the odor components of brown sugars from each province without much difference. Further, the stability, accuracy, and repeatability of the fingerprint method were verified, and speculated that the method could meet the requirements of the fingerprint. In the future, fingerprint might have wider applications due to its characteristic of distinguishing geographical origin and food adulteration. Additionally, the OPLS-DA was employed to identify the tracing of brown sugar and to identify the compounds contributing to brown sugars’ volatile classification. The results demonstrated that 4-hydroxybenzaldehyde, 3,5-dimethoxy-4-hydroxybenzaldehyde, n-hexadecanoic acid, and acetic acid were the essential components in distinguishing the sugars from Guangdong, Guangxi, and Yunnan, validating the efficiency of OPLS-DA.

Author Contributions

Methodology, H.S.; Software, Y.Z. and W.L.; Writing—original draft preparation, E.C.; Writing—review and editing, H.S. and S.Z.; Supervision, H.S. and Y.Z. All authors have read and agreed to the published version of the manuscript.

Funding

COFCO Nutrition and Health Research Institute Co., Ltd.: No number.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Acknowledgments

The present work was supported by China Oil and Food Import and Export Corporation (COFCO). No project number.

Conflicts of Interest

The authors declare no conflict of interest.

Sample Availability

Not available.

Abbreviations

GC-O-MSgas chromatography-olfactometry-mass spectrometry
LLEliquid–liquid extraction
NCSnon-centrifugal cane sugar
COFCOChina Oil and Food Import and Export Corporation
GCgas chromatography
MSmass spectrometer
ODPolfactory detection port
RSDrelative standard deviation
RTretention time
RIretention index
OPLS-DAorthogonal partial least squares discriminant analysis
VIPvariable importance of projection
OTodor threshold

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Molecules 27 05878 g001 550
Figure 1. The average content of different kinds of compounds in three regions.
Figure 1. The average content of different kinds of compounds in three regions.
Molecules 27 05878 g001
Molecules 27 05878 g002 550
Figure 2. Fingerprint of brown sugar from Guangdong, Guangxi and Yunnan.
Figure 2. Fingerprint of brown sugar from Guangdong, Guangxi and Yunnan.
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Molecules 27 05878 g003 550
Figure 3. OPLS-DA analysis and VIP diagram of brown sugar in Guangdong and Guangxi.
Figure 3. OPLS-DA analysis and VIP diagram of brown sugar in Guangdong and Guangxi.
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Molecules 27 05878 g004 550
Figure 4. OPLS-DA analysis and VIP diagram of brown sugar in Guangdong and Yunnan.
Figure 4. OPLS-DA analysis and VIP diagram of brown sugar in Guangdong and Yunnan.
Molecules 27 05878 g004
Molecules 27 05878 g005 550
Figure 5. OPLS-DA analysis and VIP diagram of brown sugar in Guangxi and Yunnan.
Figure 5. OPLS-DA analysis and VIP diagram of brown sugar in Guangxi and Yunnan.
Molecules 27 05878 g005
Table
Table 1. Volatile aroma components of brown sugars from different producing areas.
Table 1. Volatile aroma components of brown sugars from different producing areas.
No.CompoundsOdor descriptionRIIdentificationGuangdong (ng/g)Guangxi (ng/g)Yunnan (ng/g)
Guangdong1Guangdong2Guangdong3Guangdong4Guangdong5Guangdong6Guangxi1Guangxi2Guangxi3Guangxi4Guangxi5Guangxi6Yunnan1Yunnan2Yunnan3Yunnan4Yunnan5Yunnan6
12,3-butanediolfruit, onion1568MS/RI/O265.09 ± 24.94184.68 ± 20.3176.15 ± 9.36209.60 ± 19.3983.16 ± 6.00179.33 ± 13.56296.97 ± 15.27-114.44 ± 10.07256.59 ± 21.3581.45 ± 5.451019.88 ± 47.28173.87 ± 12.84256.31 ± 27.60466.38 ± 31.83410.50 ± 35.41165.52 ± 4.6150.48 ± 2.32
2propylene glycolsweet1603MS/RI/O--------75.58 ± 12.71---------
3furfuryl alcoholburnt1644MS/RI474.08 ± 15.80480.63 ± 13.93604.00 ± 40.01130.47 ± 16.31131.31 ± 6.74535.66 ± 48.232006.99 ± 23.401502.75 ± 148.15675.84 ± 18.941027.58 ± 93.40205.87 ± 11.41409.98 ± 34.42881.75 ± 15.61786.48 ± 36.72681.50 ± 47.48589.18 ± 31.7484.99 ± 5.94581.65 ± 39.11
45-methyl furfuryl alcoholsweet, caramellic1705MS/RI-----295.98 ± 33.01779.98 ± 180.99147.60 ± 7.97-303.36 ± 121.9187.16 ± 26.45325.62 ± 12.36-----189.50 ± 59.19
5benzyl alcoholsweet, flower1865MS/RI118.05 ± 16.92153.98 ± 11.55299.03 ± 22.63--17.22 ± 1.07-------169.70 ± 13.38-380.32 ± 22.02100.30 ± 7.22-
Content of total alcohols 857.22819.29979.18340.07214.471028.193083.941650.35865.861587.53374.481755.481055.621212.491147.881380350.81821.63
6hexanalgrass, tallow, fat1075MS/RI/O399.76 ± 21.53279.98 ± 19.85313.08 ± 16.32308.33 ± 6.52150.05 ± 4.55260.23 ± 19.05230.54 ± 19.8557.51 ± 4.66130.21 ± 11.55294.62 ± 15.77209.07 ± 19.25182.99 ± 15.58207.86 ± 7.5336.23 ± 2.97231.15 ± 20.79241.62 ± 17.27155.67 ± 9.51182.12 ± 16.88
7furfuralbread, almond, sweet1455MS/RI---50.05 ± 3.69--97.89 ± 3.70111.40 ± 5.8495.82 ± 6.77-108.26 ± 5.01161.29 ± 9.46-----80.62 ± 4.36
8(E)-2-nonenalcucumber, fat, green1507MS/RI/O56.20 ± 2.1295.35 ± 2.0568.21 ± 4.2071.00 ± 3.8036.96 ± 3.6985.51 ± 2.13-59.88 ± 0.2134.18 ± 3.2060.66 ± 2.6773.78 ± 5.5079.64 ± 8.9044.27 ± 2.0870.81 ± 6.62109.32 ± 12.2680.28 ± 8.59--
9benzaldehydealmond, caramel1514MS/RI/O57.98 ± 6.17109.82 ± 6.2450.92 ± 3.04--168.28 ± 3.28--46.19 ± 5.23102.28 ± 7.2852.62 ± 7.1394.52 ± 2.68-49.57 ± 4.4869.14 ± 6.6058.67 ± 4.5254.31 ± 1.43-
105-methylfurfuralalmond, caramel1560MS/RI65.10 ± 5.3260.46 ± 3.1476.48 ± 2.04---121.80 ± 7.6658.28 ± 2.6471.86 ± 6.3748.57 ± 3.8427.43 ± 1.0784.62 ± 4.31-74.75 ± 5.5989.67 ± 8.1465.65 ± 4.47-32.39 ± 2.98
112-hydroxymethyl-5-furfuralcardboard2512MS/RI527.94 ± 1.84543.97 ± 14.99840.13 ± 26.60204.68 ± 16.87---835.97 ± 5.84965.27 ± 12.27-387.49 ± 6.35559.31 ± 6.19-182.63 ± 3.23826.44 ± 9.41600.61 ± 18.03-806.60 ± 45.30
124-hydroxy-3-methoxybenzaldehydevanilla2520MS/RI1163.20 ± 28.06938.21 ± 12.55659.00 ± 12.82-930.42 ± 38.081330.74 ± 17.041123.39 ± 38.791146.19 ± 38.021256.95 ± 36.57796.62 ± 26.25707.06 ± 24.88813.25 ± 12.95282.85 ± 23.12337.09 ± 7.331009.19 ± 14.03694.32 ± 19.89562.95 ± 26.69851.26 ± 25.56
133,5-dimethoxy-4-hydroxybenzaldehydesweet, cocoa, nutty2905MS/RI/O4115.06 ± 183.573970.11 ± 230.983258.76 ± 103.024530.25 ± 115.071861.44 ± 137.601393.28 ± 152.555558.03 ± 199.50-----4106.21 ± 220.692356.17 ± 61.684986.34 ± 98.271882.87 ± 82.121255.94 ± 14.653220.19 ± 164.10
144-hydroxybenzaldehydecreamy, musty2908MS/RI-----1990.86 ± 53.37-6374.49 ± 82.326982.29 ± 125.16-3014.51 ± 138.30-------
Content of total aldehydes 6385.245997.95266.585164.312978.875228.97131.658643.729582.771302.754580.221975.624641.193107.257321.253624.022028.875173.18
152,6-di-tert-butyl-4-methylphenolcamphor1904MS/RI/O6272.71 ± 42.006702.74 ± 109.266540.27 ± 49.485238.74 ± 73.224705.80 ± 38.675559.88 ± 55.066468.03 ± 79.397106.41 ± 74.896733.20 ± 53.345149.51 ± 72.965177.12 ± 46.937033.33 ± 25.566293.40 ± 47.175659.68 ± 67.477638.60 ± 69.287938.76 ± 88.455115.72 ± 52.863851.64 ± 64.59
164-ethenyl-2-methoxyphenolclove, curry2168MS/RI3571.11 ± 211.983749.85 ± 126.323296.40 ± 110.643640.61 ± 173.252405.55 ± 54.023822.00 ± 212.873438.47 ± 193.671672.14 ± 135.594249.96 ± 176.214588.34 ± 344.501419.61 ± 117.812766.58 ± 282.453400.23 ± 161.643112.76 ± 217.964595.74 ± 345.423222.71 ± 211.172317.34 ± 178.281808.79 ± 133.86
172,4-di-tert-butylphenolphenolic2292MS/RI644.13 ± 80.76456.81 ± 31.921052.57 ± 17.01765.57 ± 39.53332.60 ± 19.04947.69 ± 13.411292.16 ± 26.55-1359.89 ± 78.31467.47 ± 30.26323.04 ± 21.631207.83 ± 109.14446.63 ± 20.55684.35 ± 35.98675.77 ± 60.09705.89 ± 49.64498.28 ± 14.81558.50 ± 25.05
182-methoxy-4-propenylphenolflower2250MS/RI----149.00 ± 15.25------------391.82 ± 19.80
19(E)-4-propenyl-2-methoxyphenolflower2315MS/RI630.45 ± 15.19622.41 ± 11.80689.57 ± 19.91--372.06 ± 21.68605.14 ± 18.49-----619.56 ± 48.92563.39 ± 38.89907.11 ± 87.87662.54 ± 23.60434.79 ± 35.66-
204-allyl-2,6-dimethoxyphenolsweet, flower2510MS/RI/O-----72.86 ± 9.71440.73 ± 32.29-243.43 ± 15.50---129.33 ± 13.43--269.60 ± 18.11132.49 ± 14.66-
214-ethenyl-2,6-dimethoxy-phenolanimal leather2541MS/RI893.16 ± 23.65799.51 ± 17.03916.48 ± 36.36655.80 ± 23.22321.18 ± 28.46835.89 ± 38.061183.04 ± 31.14803.61 ± 72.231461.19 ± 29.311365.67 ± 76.92746.52 ± 42.58634.98 ± 13.65572.43 ± 51.73807.85 ± 70.451249.40 ± 36.451069.77 ± 73.55718.19 ± 34.311237.55 ± 79.52
222-methoxy-4-acetylphenolvanilla2640MS/RI/O----352.34 ± 24.92-693.73 ± 55.31808.51 ± 34.53638.98 ± 11.431094.03 ± 62.69935.46 ± 64.81584.08 ± 42.12855.15 ± 69.12---669.33 ± 59.70649.86 ± 47.29
Content of total phenols 12,011.5612,331.3212,495.2910,300.728266.4711,610.3814,121.310,390.6714,686.6512,665.028601.7512,226.812,316.7310,828.0315,066.6213,869.279886.148498.16
23acetic acidsour1415MS/RI/O10,184.79 ± 464.5310,757.27 ± 305.672778.13 ± 46.396350.81 ± 222.216432.09 ± 175.475900.64 ± 582.426650.69 ± 245.634210.80 ± 330.792977.92 ± 249.8410,999.92 ± 407.675047.46 ± 287.2111,141.62 ± 393.704237.56 ± 172.971068.38 ± 53.5212,748.83 ± 163.899209.62 ± 249.195570.25 ± 363.1810,334.03 ± 261.79
24formic acidacetic, astringent, fruity1489MS/RI/O249.89 ± 11.00123.64 ± 7.91219.04 ± 9.56195.29 ± 11.2684.47 ± 6.0396.96 ± 8.18------91.75 ± 13.52-389.25 ± 20.61426.15 ± 37.81-286.39 ± 23.78
25propanoic acidpungent, rancid, soy1526MS/RI/O821.24 ± 27.91619.01 ± 37.09644.68 ± 16.61396.79 ± 26.64303.37 ± 5.15260.37 ± 16.25332.73 ± 19.43147.19 ± 14.68329.19 ± 2.45457.22 ± 9.98280.06 ± 14.46653.58 ± 28.53425.26 ± 19.38299.24 ± 25.791143.61 ± 18.50994.93 ± 49.00515.40 ± 13.38344.61 ± 26.73
262-methylpropionic acidrancid, butter, cheese1563MS/RI519.47 ± 21.24325.82 ± 19.73264.85 ± 9.33120.82 ± 9.90166.03 ± 2.884.00 ± 0.24--88.45 ± 8.92278.92 ± 25.60272.22 ± 18.48322.66 ± 11.67-153.86 ± 29.30621.60 ± 24.32768.20 ± 37.42342.05 ± 10.18-
27butanoic acidrancid, cheese, sweat1607MS/RI/O2660.81 ± 89.682644.03 ± 91.30614.21 ± 9.492513.84 ± 26.281227.91 ± 39.851421.39 ± 43.73810.96 ± 56.86192.43 ± 16.791269.77 ± 80.471178.36 ± 29.86168.86 ± 8.63440.72 ± 17.861266.55 ± 13.63837.56 ± 53.384204.64 ± 71.972118.54 ± 37.341154.60 ± 33.74-
283-methylbutanoic acidsweat, acid, rancid1665MS/RI/O1633.63 ± 125.321076.75 ± 113.20645.70 ± 71.56306.69 ± 15.93-12.90 ± 0.34271.65 ± 16.23116.04 ± 14.73218.33 ± 20.09884.46 ± 15.52810.07 ± 53.66710.73 ± 29.151123.49 ± 87.06566.92 ± 16.791390.95 ± 38.951609.20 ± 36.46--
292-methylbutanoic acidcheese, sweat1651MS/RI/O-----373.25 ± 28.50------------
302-methylpentanoic acidbuttery, creamy1728MS/RI/O---183.26 ± 5.52-37.89 ± 3.86----------302.40 ± 19.20-
314-methylpentanoic acidpungent cheese1820MS/RI/O----------------119.80 ± 6.8356.28 ± 4.95
32hexanoic acidsweat1826MS/RI/O300.51 ± 7.89597.73 ± 14.47487.13 ± 17.43280.13 ± 27.04283.56 ± 12.23435.09 ± 35.20280.31 ± 18.91-155.31 ± 12.61453.98 ± 23.33119.62 ± 11.23112.67 ± 9.39580.84 ± 13.70441.59 ± 28.07727.74 ± 38.34728.69 ± 15.97383.25 ± 13.9378.31 ± 3.80
33octanoic acidsweat, cheese2083MS/RI/O228.77 ± 6.47267.60 ± 21.47-----------262.06 ± 13.93252.12 ± 24.62487.06 ± 38.82--
34nonanoic acidgreen, fat2147MS/RI/O-----413.10 ± 28.63-----------227.94 ± 12.15
35levulinic acidacidic, sweet, creamy2312MS/RI587.58 ± 22.24584.31 ± 18.74589.85 ± 16.89-----306.63 ± 20.02-338.16 ± 17.34530.63 ± 35.66--653.12 ± 14.73424.09 ± 35.11--
36benzoic acidurine2392MS/RI/O3080.65 ± 130.043564.46 ± 241.544062.78 ± 303.132709.59 ± 234.741609.97 ± 79.531795.59 ± 129.383194.93 ± 194.091982.81 ± 136.802736.59 ± 235.523573.53 ± 145.401480.40 ± 134.072837.50 ± 175.532965.81 ± 197.601857.28 ± 192.934446.03 ± 192.354751.21 ± 272.411872.63 ± 65.712262.00 ± 138.28
37dodecanoic acidmetal2517MS/RI555.78 ± 15.49708.53 ± 18.03575.78 ± 16.57215.12 ± 19.98---------438.26 ± 33.22750.95 ± 39.27504.14 ± 42.56222.18 ± 21.86-
38phenylacetic acidhoney, flower2551MS/RI/O1468.96 ± 56.271173.77 ± 75.041187.97 ± 92.84880.89 ± 63.45730.30 ± 47.8147.37 ± 3.631267.41 ± 64.32-945.30 ± 61.581180.95 ± 82.76741.94 ± 40.051353.01 ± 89.13526.12 ± 26.32903.11 ± 25.211487.08 ± 19.131976.49 ± 49.24747.98 ± 54.78606.57 ± 35.96
393-phenylpropionic acidbalsamic2650MS/RI/O---156.03 ± 11.33-10.79 ± 0.95------------
40tetradecanoic acidsweet, spicy, carnation2674MS/RI821.53 ± 67.391273.66 ± 98.64457.82 ± 19.58--173.22 ± 16.83-------498.30 ± 17.36975.39 ± 21.75631.33 ± 10.41252.25 ± 17.50-
41pentadecanoic acidwaxy2784MS/RI/O904.37 ± 37.761205.19 ± 44.08867.02 ± 48.07423.32 ± 20.01-806.02 ± 71.41586.50 ± 17.13------733.11 ± 17.631093.45 ± 76.47886.36 ± 59.46381.02 ± 26.80-
423-phenyl-2-propenoic acidbalsam, sweet, storax2815MS/RI-502.70 ± 18.02--329.63 ± 27.74555.52 ± 31.40693.22 ± 19.57--1366.71 ± 46.48904.32 ± 31.86502.43 ± 39.39--871.20 ± 27.75491.13 ± 25.65416.66 ± 18.74-
43n-hexadecanoic acidfatty2903MS/RI11,549.66 ± 283.9212,914.61 ± 160.728039.99 ± 159.006586.75 ± 270.874432.49 ± 192.778965.43 ± 247.846422.49 ± 176.2613,536.74 ± 152.683748.63 ± 233.1317,908.48 ± 240.925811.71 ± 96.263458.70 ± 197.369174.60 ± 92.176027.10 ± 231.0815,086.68 ± 176.079036.63 ± 202.893926.92 ± 280.514354.01 ± 214.68
Content of total carboxylic acids 35,567.6438,339.0821,434.9521,319.3315,599.8221,309.5320,510.8920,186.0112,776.1238,282.5315,974.8222,064.2520,391.9814,086.7746,842.6435,043.7716,207.3918,550.14
442-methyl-4,5-dihydro-3(2H)-furanonenutty, creamy1253MS/RI/O341.22 ± 28.421177.87 ± 50.20513.32 ± 23.30276.67 ± 4.5270.39 ± 4.46327.17 ± 28.81202.04 ± 17.85291.29 ± 28.0793.57 ± 6.69712.73 ± 89.42141.35 ± 12.32173.07 ± 3.56701.59 ± 29.981141.42 ± 76.00391.82 ± 12.71578.35 ± 18.67726.04 ± 22.751389.22 ± 47.00
453-hydroxy-2-butanonebutter, cream1272MS/RI91.84 ± 7.28126.67 ± 7.48124.74 ± 9.98103.62 ± 3.31-163.28 ± 2.03253.98 ± 9.70145.05 ± 8.2147.80 ± 1.02123.45 ± 4.6632.46 ± 4.6968.52 ± 1.1597.36 ± 7.8874.92 ± 5.1479.07 ± 3.5380.41 ± 3.6656.30 ± 2.47105.69 ± 8.71
461-hydroxy-2-propanonesweet1287MS/RI/O457.94 ± 39.12582.30 ± 18.77605.26 ± 9.93438.74 ± 12.52206.31 ± 12.44652.59 ± 47.59841.13 ± 59.74715.56 ± 23.75503.38 ± 2.41505.10 ± 33.50220.33 ± 5.58211.55 ± 20.44458.82 ± 7.71360.04 ± 29.17382.45 ± 17.01461.70 ± 11.83355.89 ± 14.98438.74 ± 30.24
471-hydroxy-2-butanoneoily, alcoholic1375MS/RI/O39.22 ± 2.39111.06 ± 5.9741.37 ± 3.7443.91 ± 3.57-16.70 ± 0.68-76.40 ± 7.7582.88 ± 4.4062.58 ± 4.71-24.26 ± 1.3156.34 ± 6.7746.29 ± 6.8963.27 ± 6.8356.43 ± 3.28--
481-acetoxy-2-propanonefruity, nutty1451MS/RI/O118.22 ± 4.77230.25 ± 15.43187.71 ± 12.77168.77 ± 15.67-66.52 ± 6.06218.30 ± 12.12159.99 ± 17.64115.45 ± 11.12245.41 ± 19.90139.08 ± 6.91235.11 ± 24.82176.14 ± 11.14191.49 ± 11.15132.61 ± 7.14177.62 ± 9.60125.30 ± 4.14131.45 ± 4.25
494,5-dihydro-5-methyl-2(3H)-furanonesweet, cocoa, woody1590MS/RI65.34 ± 7.38113.07 ± 5.9389.27 ± 2.10------------90.38 ± 5.27--
502(5H)-furanonebuttery1727MS/RI/O475.08 ± 10.84581.86 ± 9.05479.55 ± 13.75--145.49 ± 10.40394.39 ± 11.56265.72 ± 18.69286.88 ± 27.60221.84 ± 19.51203.23 ± 15.77363.54 ± 28.70-232.91 ± 14.77712.75 ± 37.46266.08 ± 24.57-154.22 ± 8.91
513-methyl-1,2-cyclopentanedionesweet, maple, bready1781MS/RI/O-----------------361.67 ± 24.53
522-hydroxy-3-methyl-2-cyclopenten-1-onecaramellic1807MS/RI/O468.60 ± 24.21482.48 ± 34.60707.42 ± 68.00283.22 ± 26.02182.61 ± 11.36588.56 ± 57.85879.99 ± 59.16726.67 ± 69.62745.18 ± 66.72519.02 ± 24.12186.46 ± 22.90476.39 ± 46.95681.71 ± 49.56637.34 ± 38.58716.33 ± 14.99684.63 ± 28.94248.07 ± 2.51-
533-hydroxyl-2-methyl-4H-pyran-4-onecaramel1931MS/RI----------------201.59 ± 23.7494.06 ± 7.11
542(3H)-furanonecotton candy2002MS/RI/O974.60 ± 62.46721.47 ± 64.381069.93 ± 92.52351.84 ± 39.07292.08 ± 13.56470.52 ± 30.39631.95 ± 22.11615.99 ± 36.85655.84 ± 55.61705.84 ± 16.73496.09 ± 31.24977.50 ± 56.20560.98 ± 8.63596.89 ± 59.041123.58 ± 46.281324.65 ± 17.01397.11 ± 16.87323.38 ± 29.23
552,5-dimethyl-4-hydroxy-3(2H)-furanonecaramel2012MS/RI/O271.76 ± 26.35326.77 ± 19.05454.38 ± 18.37230.03 ± 13.34123.31 ± 4.96731.60 ± 15.542168.59 ± 55.501158.64 ± 13.07298.58 ± 23.33471.80 ± 39.5269.64 ± 3.26144.05 ± 13.78415.29 ± 14.57861.94 ± 90.58625.51 ± 26.54529.53 ± 18.15-141.69 ± 16.00
564-hydroxy-5-methyl-3-(2H)-furanonecaramel2113MS/RI/O---181.54 ± 21.75-19.69 ± 1.35612.25 ± 48.80----------99.22 ± 7.93
574-hydroxyacetophenonesweet2958MS/RI/O1461.87 ± 17.591892.62 ± 25.111469.22 ± 34.48---1546.24 ± 57.40------1656.02 ± 57.982234.53 ± 34.421370.88 ± 77.571132.23 ± 64.94-
Content of total ketones 4765.696346.425742.172078.34874.73182.127748.864155.312829.563567.771488.642673.993148.235799.266461.925620.663242.533239.34
58dimethyl butanedioatesweet, fruity, green1558MS/RI---------590.16 ± 16.86--120.03 ± 12.32-----
59γ-butyrolactonecaramel, sweet1647MS/RI-----------------193.04 ± 34.38
60dimethyl glutaratefloral1687MS/RI---------2030.19 ± 99.86--1039.76 ± 40.69-----
61benzyl benzoatebalsamic, oil, herb2592MS/RI---205.81 ± 17.70-503.82 ± 28.75621.78 ± 52.33-503.64 ± 41.22-431.15 ± 37.87482.89 ± 31.13510.18 ± 36.70381.49 ± 27.23682.59 ± 34.84514.18 ± 27.27--
62dibutyl phthalatefaint odor2705MS/RI1264.25 ± 33.841113.96 ± 65.74810.31 ± 68.931061.36 ± 22.53979.13 ± 65.98373.31 ± 25.221089.36 ± 16.24-1202.60 ± 47.72977.92 ± 29.04735.97 ± 19.95-2530.75 ± 52.67-1333.62 ± 38.032536.41 ± 162.39955.08 ± 69.591694.09 ± 93.37
Content of total esters 1264.251113.96810.311267.17979.13877.131711.1401706.243598.271167.12482.894200.72381.492016.213050.59955.081887.13
632-methylpyrazinepopcorn1259MS/RI366.92 ± 30.48662.33 ± 40.09159.11 ± 11.85402.41 ± 7.65112.41 ± 5.11854.10 ± 77.77651.18 ± 27.24500.27 ± 17.30235.82 ± 8.38561.03 ± 42.7176.46 ± 1.5646.44 ± 5.46289.74 ± 9.95196.65 ± 14.01172.90 ± 15.26203.79 ± 21.1988.40 ± 1.38-
642,5-dimethylpyrazinecocoa, nutty, roast beef1321MS/RI/O924.49 ± 34.201938.05 ± 101.57111.73 ± 10.50963.30 ± 10.96201.81 ± 14.821827.76 ± 35.721343.97 ± 86.27989.09 ± 53.501309.65 ± 15.591748.65 ± 121.6788.92 ± 6.0770.87 ± 2.231114.25 ± 44.64703.42 ± 34.33419.79 ± 28.03430.64 ± 21.63375.15 ± 3.7393.56 ± 8.17
652,6-dimethylpyrazinenutty, cocoa, roast beef1326MS/RI/O682.76 ± 22.041035.34 ± 80.61144.76 ± 15.74983.96 ± 18.8172.49 ± 6.851094.56 ± 26.511444.15 ± 48.601045.87 ± 46.22800.00 ± 42.14946.87 ± 86.0568.92 ± 14.8585.72 ± 11.44693.95 ± 41.35273.74 ± 19.98230.77 ± 22.95289.35 ± 16.10139.77 ± 2.60208.04 ± 17.25
662,3-dimethylpyrazinenutty, cocoa, meat1343MS/RI125.46 ± 9.27231.83 ± 13.1456.13 ± 2.20-38.84 ± 3.35325.66 ± 36.06253.09 ± 14.24142.65 ± 9.6672.47 ± 5.15216.09 ± 18.8110.89 ± 1.38-152.68 ± 11.6573.56 ± 4.4875.96 ± 6.3070.09 ± 5.0142.31 ± 1.02-
672-ethyl-6-methylpyrazineroasted hazelnut1382MS/RI69.27 ± 2.41157.44 ± 5.95-92.61 ± 1.8713.81 ± 2.7888.18 ± 9.04165.64 ± 5.86114.68 ± 7.4358.06 ± 6.05167.14 ± 12.1114.91 ± 1.3319.91 ± 1.53153.89 ± 9.4466.03 ± 4.6752.17 ± 4.6246.08 ± 2.7921.31 ± 0.765.15 ± 0.38
682-ethyl-5-methylpyrazinefruit, sweet1376MS/RI55.63 ± 6.94227.21 ± 18.30----151.24 ± 10.05139.24 ± 7.77123.72 ± 3.04178.42 ± 6.03-21.87 ± 0.6588.57 ± 8.00105.86 ± 13.64129.60 ± 16.4277.52 ± 8.13--
692,3,5-trimethylpyrazineroast, potato, must1405MS/RI/O---180.76 ± 15.9035.78 ± 3.42306.68 ± 21.34249.04 ± 14.64250.84 ± 14.8540.86 ± 3.21-46.57 ± 3.30--125.18 ± 7.11---33.86 ± 3.99
702,5-dimethyl-3-ethylpyrazinepotato, roast1445MS/RI/O151.21 ± 12.91315.82 ± 12.23-157.83 ± 2.51-338.49 ± 32.43------109.14 ± 7.37201.75 ± 16.35138.27 ± 14.70119.00 ± 1.38--
712,6-dimethyl-3-ethylpyrazinepotato1455MS/RI/O----79.78 ± 4.61186.16 ± 12.73412.18 ± 36.51272.34 ± 16.48203.53 ± 6.05286.15 ± 18.85------82.88 ± 8.05-
722-methyl-6-vinylpyrazinehazelnut1487MS/RI-----177.67 ± 24.80688.17 ± 39.07665.08 ± 41.61311.55 ± 14.08-181.63 ± 8.49550.08 ± 34.15-133.21 ± 8.77----
732-acetyl-5-methylpyrazinepopcorn1664MS/RI/O---156.34 ± 13.27-218.85 ± 16.63------------
742-acetyl-6-methylpyrazinecoffee, cocoa, popcorn1673MS/RI/O251.42 ± 21.79419.45 ± 28.68-141.33 ± 9.04-245.73 ± 14.16183.55 ± 23.20144.23 ± 7.83121.93 ± 11.22218.58 ± 16.46---408.61 ± 9.22-113.67 ± 8.1996.94 ± 7.01-
Content of total pyrazines 2627.164987.47471.733078.54554.925663.845542.214264.293277.594322.93488.3794.892602.222288.011219.461350.14846.76340.61
752-acetylpyrrolenutty, walnut, bread1947MS/RI679.69 ± 54.14856.53 ± 39.091676.37 ± 66.60531.22 ± 38.42111.84 ± 5.12791.31 ± 37.882227.41 ± 88.132964.65 ± 58.722703.33 ± 101.11747.17 ± 33.20461.32 ± 47.831263.31 ± 41.84855.32 ± 80.101610.00 ± 150.67942.57 ± 99.061761.17 ± 84.121298.42 ± 59.86971.33 ± 70.56
762-acetylfuranbalsamic1490MS/RI/O-----5.27 ± 0.85-231.24 ± 17.91103.74 ± 7.62-37.99 ± 2.0572.73 ± 1.11-----54.65 ± 3.48
77(+)-limonenecitrus, mint1201MS/RI----48.67 ± 3.12-210.31 ± 21.01---71.37 ± 2.8599.25 ± 2.6369.37 ± 7.7469.29 ± 5.8189.42 ± 6.5551.53 ± 3.80--
78phenylethylenebalsamic, gasoline1247MS/RI/O651.29 ± 54.83613.81 ± 14.74573.68 ± 15.42451.99 ± 11.84160.07 ± 12.09457.61 ± 37.97546.32 ± 24.83469.44 ± 28.01511.72 ± 22.34984.77 ± 64.37984.42 ± 73.211025.24 ± 14.21500.79 ± 9.91459.13 ± 34.72564.51 ± 15.57601.32 ± 18.81471.01 ± 19.63162.20 ± 23.00
79methyl sulfoxidegarlic1576MS/RI151.90 ± 19.28176.80 ± 8.9263.28 ± 7.1989.59 ± 3.8249.16 ± 4.142.89 ± 1.67-------178.52 ± 18.72237.91 ± 15.70207.83 ± 13.45151.60 ± 18.1942.30 ± 4.61
801,3-dimethoxy-2-hydroxybenzenemedicine, phenol, smoke2296MS/RI------------1138.32 ± 54.20-----
Content of other compounds 1482.881647.142313.331072.8369.741257.082984.043665.333318.791731.941555.12460.532563.82316.941834.412621.851921.031230.48
Total identified/detected 64,961.6471,582.5849,513.5444,621.2829,838.1250,157.1762,834.0352,955.6849,043.5867,058.7434,230.4344,434.4550,920.4940,020.2481,910.3966,560.335,438.6139,740.67
Table
Table 2. OAV of key odor compounds in brown sugar.
Table 2. OAV of key odor compounds in brown sugar.
No.Compounds aOT (ng/g) bGD1GD2GD3GD4GD5GD6GX1GX2GX3GX4GX5GX6YN1YN2YN3YN4YN5YN6
1pentadecanoic acid5002221-21------1221-
22-methylbutanoic acid20-----19------------
33-methylbutanoic acid1.8908598359170-715164121491450395624315773894--
44-methylpentanoic acid1.9----------------6330
5acetic acid1378382721448949545451232422984638885732682981708428795
6benzoic acid1000344322323413324522
7butanoic acid2013313231126617141106359822634221010658-
8hexanoic acid4.86312510158599158-32952523121921521528016
9nonanoic acid1.6-----258-----------142
10octanoic acid221012-----------121122--
11phenylacetic acid178669705243375-566944803153871164436
12hexanal1.4286200224220107186165419321014913114826165173111130
13(E)-2-nonenal0.19296502359374195450-315180319388419233373575423--
143,5-dimethoxy-4-hydroxybenzaldehyde19002222113-----213112
15benzaldehyde60121--3--1212-1111-
163-methyl-1,2-cyclopentanedione26-----------------14
172-hydroxy-3-methyl-2-cyclopenten-1-one104748712818598873755219486864726825-
182,5-dimethyl-4-hydroxy-3(2H)-furanone1.61702042841447745713557241872954490260539391331-89
194-hydroxy-5-methyl-3-(2H)-furanone500---<1-<11----------<1
20phenylethylene371817161241215131427272814121516134
21furfuryl alcohol1415<1<1<1<1<1<111<11<1<111<1<1<1<1
222,3,5-trimethylpyrazine23---821311112-2--5---1
232,5-dimethylpyrazine80122411232317121622111495551
242,6-dimethyl-3-ethylpyrazine0.04----1995465410,305680950887154------2072-
252,6-dimethylpyrazine2503414<146434<1<1311111
262-acetyl-6-methylpyrazine30011-<1-11<1<11---1-<1<1-
a Volatile compounds that can be smelled at sniffer port. b Odor thresholds were referenced in a book, named: odor thresholds compilations of odor threshold values in air, water and other media.
Table
Table 3. Fingerprint results of brown sugar from each producing area.
Table 3. Fingerprint results of brown sugar from each producing area.
No.CompoundsGuangdongGuangxiYunnan
Guangdong1Guangdong2Guangdong3Guangdong4Guangdong5Guangdong6Guangxi1Guangxi2Guangxi3Guangxi4Guangxi5Guangxi6Yunnan1Yunnan2Yunnan3Yunnan4Yunnan5Yunnan6
12,3-butanediol265.09184.6876.15209.683.16179.33296.970114.44256.5981.451019.88173.87256.31466.38410.5165.5250.48
2propylene glycol0000000075.58000000000
3hexanal399.76279.98313.08308.33150.05260.23230.5457.51130.21294.62209.07182.99207.8636.23231.15241.62155.67182.12
4(E)-2-nonenal56.295.3568.217136.9685.51059.8834.1860.6673.7879.6444.2770.81109.3280.2800
5benzaldehyde57.98109.8250.9200168.280046.19102.2852.6294.52049.5769.1458.6754.310
63,5-dimethoxy-4-hydroxybenzaldehyde4115.063970.113258.764530.251861.441393.285558.03000004106.212356.174986.341882.871255.943220.19
72,6-di-tert-butyl-4-methylphenol6272.716702.746540.275238.744705.85559.886468.037106.416733.25149.515177.127033.336293.45659.687638.67938.765115.723851.64
84-allyl-2,6-dimethoxyphenol0000072.86440.730243.43000129.3300269.6132.490
92-methoxy-4-acetylphenol0000352.340693.73808.51638.981094.03935.46584.08855.15000669.33649.86
10acetic acid10,184.7910,757.272778.136350.816432.095900.646650.694210.82977.9210,999.925047.4611,141.624237.561068.3812,748.839209.625570.2510,334.03
11methanoic acid249.89123.64219.04195.2984.4796.9600000091.750389.25426.150286.39
12propanoic acid821.24619.01644.68396.79303.37260.37332.73147.19329.19457.22280.06653.58425.26299.241143.61994.93515.4344.61
13butanoic acid2660.812644.03614.212513.841227.911421.39810.96192.431269.771178.36168.86440.721266.55837.564204.642118.541154.60
143-methylbutanoic acid1633.631076.75645.7306.69012.9271.65116.04218.33884.46810.07710.731123.49566.921390.951609.200
152-methylbutanoic acid00000373.25000000000000
162-methylpentanoic acid000183.26037.890000000000302.40
174-methylpentanoic acid0000000000000000119.856.28
18hexanoic acid300.51597.73487.13280.13283.56435.09280.310155.31453.98119.62112.67580.84441.59727.74728.69383.2578.31
19octanoic acid228.77267.600000000000262.06252.12487.0600
20nonanoic acid00000413.100000000000227.94
21benzoic acid3080.653564.464062.782709.591609.971795.593194.931982.812736.593573.531480.42837.52965.811857.284446.034751.211872.632262
22phenylacetic acid1468.961173.771187.97880.89730.347.371267.410945.31180.95741.941353.01526.12903.111487.081976.49747.98606.57
233-phenylpropionic acid000156.03010.79000000000000
24pentadecanoic acid904.371205.19867.02423.320806.02586.5000000733.111093.45886.36381.020
252-methyl-4,5-dihydro-3(2H)-furanone341.221177.87513.32276.6770.39327.17202.04291.2993.57712.73141.35173.07701.591141.42391.82578.35726.041389.22
261-hydroxy-2-propanone457.94582.3605.26438.74206.31652.59841.13715.56503.38505.1220.33211.55458.82360.04382.45461.7355.89438.74
271-hydroxy-2-butanone39.22111.0641.3743.91016.7076.482.8862.58024.2656.3446.2963.2756.4300
281-acetoxy-2-propanone118.22230.25187.71168.77066.52218.3159.99115.45245.41139.08235.11176.14191.49132.61177.62125.3131.45
292(5H)-furanone475.08581.86479.5500145.49394.39265.72286.88221.84203.23363.540232.91712.75266.080154.22
303-methyl-1,2-cyclopentanedione00000000000000000361.67
312-hydroxy-3-methyl-2-cyclopenten-1-one468.6482.48707.42283.22182.61588.56879.99726.67745.18519.02186.46476.39681.71637.34716.33684.63248.070
322(3H)-furanone974.6721.471069.93351.84292.08470.52631.95615.99655.84705.84496.09977.5560.98596.891123.581324.65397.11323.38
332,5-dimethyl-4-hydroxy-3(2H)-furanone271.76326.77454.38230.03123.31731.62168.591158.64298.58471.869.64144.05415.29861.94625.51529.530141.69
344-hydroxy-5-methyl-3-(2H)-furanone000181.54019.69612.25000000000099.22
354-hydroxyacetophenone1461.871892.621469.220001546.240000001656.022234.531370.881132.230
362,5-dimethylpyrazine924.491938.05111.73963.3201.811827.761343.97989.091309.651748.6588.9270.871114.25703.42419.79430.64375.1593.56
372,6-dimethylpyrazine682.761035.34144.76983.9672.491094.561444.151045.87800946.8768.9285.72693.95273.74230.77289.35139.77208.04
382,3,5-trimethylpyrazine000180.7635.78306.68249.04250.8440.86046.5700125.1800033.86
392,5-dimethyl-3-ethylpyrazine151.21315.820157.830338.49000000109.14201.75138.2711900
402,6-dimethyl-3-ethylpyrazine000079.78186.16412.18272.34203.53286.1500000082.880
412-acetyl-5-methylpyrazine000156.340218.85000000000000
422-acetyl-6-methylpyrazine251.42419.450141.330245.73183.55144.23121.93218.58000408.610113.6796.940
432-acetylfuran000005.270231.24103.74037.9972.730000054.65
44phenylethylene651.29613.81573.68451.99160.07457.61546.32469.44511.72984.77984.421025.24500.79459.13564.51601.32471.01162.2
Cosine of included angle0.98790.98880.88550.98000.97500.96430.90310.94630.91520.95270.97760.96710.94390.81550.98150.98390.98220.9189
Similarity0.98500.98590.85620.97520.97810.95530.88240.93730.89800.94450.97620.96640.93000.76550.97730.97990.97870.9138
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Chen, E.; Zhao, S.; Song, H.; Zhang, Y.; Lu, W. Analysis and Comparison of Aroma Compounds of Brown Sugar in Guangdong, Guangxi and Yunnan Using GC-O-MS. Molecules 2022, 27, 5878. https://doi.org/10.3390/molecules27185878

AMA Style

Chen E, Zhao S, Song H, Zhang Y, Lu W. Analysis and Comparison of Aroma Compounds of Brown Sugar in Guangdong, Guangxi and Yunnan Using GC-O-MS. Molecules. 2022; 27(18):5878. https://doi.org/10.3390/molecules27185878

Chicago/Turabian Style

Chen, Erbao, Shuna Zhao, Huanlu Song, Yu Zhang, and Wanyao Lu. 2022. "Analysis and Comparison of Aroma Compounds of Brown Sugar in Guangdong, Guangxi and Yunnan Using GC-O-MS" Molecules 27, no. 18: 5878. https://doi.org/10.3390/molecules27185878

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