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Oolong tea made from tea plants from different locations in Yunnan and Fujian, China showed similar aroma but different taste characteristics

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Consistent aroma characteristics are important for tea products. However, understanding the formation of tea aroma flavor and correspondingly proposing applicable protocols to control tea quality and consistency remain major challenges. Oolong tea is one of the most popular teas with a distinct flavor. Generally, oolong tea is processed with the leaves of tea trees belonging to different subspecies and grown in significantly different regions. In this study, Yunnan and Fujian oolong teas, green tea, black tea, and Pu-erh tea were collected from major tea estates across China. Their sensory evaluation, main water-soluble and volatile compounds were identified and measured. The sensory evaluation, total polysaccharide, caffeine, and catechin content of Yunnan oolong tea was found to be different from that of Fujian oolong tea, a result suggesting that the kinds of tea leaves used in Yunnan and Fujian oolong teas were naturally different. However, according to their aroma compounds, principal component analysis (PCA) and cluster analysis (CA) of the volatile compounds showed that the two types of oolong teas were similar and cannot be clearly distinguished from each other; they are also different from green, black, and Pu-erh teas, a result indicating that the same oolong tea processing technology applied to different tea leaves results in consistent aroma characteristics. The PCA analysis results also indicated that benzylalcohol, indole, safranal, linalool oxides, β-ionone, and hexadecanoic acid methyl ester highly contributed to the distinct aroma of oolong tea compared with the other three types of teas. This study proved that the use of the same processing technology on two kinds of tea leaves resulted in a highly consistent tea aroma.
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Oolong tea made fromtea plants
fromdierent locations inYunnan andFujian,
China showed similar aroma butdierent taste
characteristics
Chen Wang1†, Shidong Lv2†, Yuanshuang Wu1, Xuemei Gao1, Jiangbing Li1, Wenrui Zhang1
and Qingxiong Meng1*
Background
Oolong tea is a kind of partially fermented tea. It has become one of the most popular bev-
erages in China because of its sweet grassy taste and unique flower-like aroma. Traditional
oolong tea is produced with Camellia sinensis var. sinensis (China type) from Fujian Province
in southeast China. However, because of the limited raw tea produced in Fujian Province, tea
Abstract
Consistent aroma characteristics are important for tea products. However, under-
standing the formation of tea aroma flavor and correspondingly proposing applicable
protocols to control tea quality and consistency remain major challenges. Oolong tea
is one of the most popular teas with a distinct flavor. Generally, oolong tea is processed
with the leaves of tea trees belonging to different subspecies and grown in signifi-
cantly different regions. In this study, Yunnan and Fujian oolong teas, green tea, black
tea, and Pu-erh tea were collected from major tea estates across China. Their sensory
evaluation, main water-soluble and volatile compounds were identified and measured.
The sensory evaluation, total polysaccharide, caffeine, and catechin content of Yunnan
oolong tea was found to be different from that of Fujian oolong tea, a result suggesting
that the kinds of tea leaves used in Yunnan and Fujian oolong teas were naturally dif-
ferent. However, according to their aroma compounds, principal component analysis
(PCA) and cluster analysis (CA) of the volatile compounds showed that the two types
of oolong teas were similar and cannot be clearly distinguished from each other; they
are also different from green, black, and Pu-erh teas, a result indicating that the same
oolong tea processing technology applied to different tea leaves results in consistent
aroma characteristics. The PCA analysis results also indicated that benzylalcohol, indole,
safranal, linalool oxides, β-ionone, and hexadecanoic acid methyl ester highly contrib-
uted to the distinct aroma of oolong tea compared with the other three types of teas.
This study proved that the use of the same processing technology on two kinds of tea
leaves resulted in a highly consistent tea aroma.
Keywords: Oolong tea, Main water-soluble contents, Volatile compounds, Processing
technology, Aroma characteristics
Open Access
© 2016 The Author(s). This article is distributed under the terms of the Creative Commons Attribution 4.0 International License
(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium,
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indicate if changes were made.
RESEARCH
Wang et al. SpringerPlus (2016) 5:576
DOI 10.1186/s40064-016-2229-y
*Correspondence:
qxmeng@scbg.ac.cn
Chen Wang and Shidong
Lv contribute equally to this
work should be regarded as
co-first authors
1 Faculty of Life Science
and Technology, Kunming
University of Science
and Technology,
Kunming 650500, Yunnan,
People’s Republic of China
Full list of author information
is available at the end of the
article
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Wang et al. SpringerPlus (2016) 5:576
buds grown in other locations and from different tea tree subspecies have also been used for
oolong tea in recent years; an example is Camellia sinensis var. assamica (Assam type), which
is mainly distributed in Yunnan Province in southwest China, especially the districts around
Pu-erh (Lv etal. 2014a). ese two tea subspecies grown in different locations show obvious
differences, such as the sizes of their leaves and their water-soluble components (Liang etal.
2005). Until now, however, little known about the similarities and dissimilarities of these two
oolong teas. To determine their consistency in taste, we analyzed the caffeine, catechin, total
polysaccharide, and volatile components of Yunnan and Fujian oolong teas and compared
them with those of other common types of teas.
Main water-soluble components, such as caffeine, polysaccharides, and catechins (Zhu
etal. 2015; Nie etal. 2011), are generally responsible for the taste of tea fusion, whereas
volatile components contribute to tea aroma. In tea, volatile components are only pre-
sent in about 0.01% of the total dry weight, but they result in a high odor experience
because of their low threshold value (Rawat etal. 2007). Whereas water-soluble content
is naturally influenced by geographical characteristics, climate, tea cultivar, and process-
ing technology applied on raw leaves, volatile compound content can be influenced and
transformed by the processing technology used on the leaves (Fernández-Cáceres etal.
2001; Narukawa etal. 2011). Volatile compounds are transformed from water-soluble
components during processing steps, such as fermentation, post-fermentation, and bak-
ing (Hara etal. 1995). For example, Yunnan and Fujian oolong teas are both partially fer-
mented by the same processing technology with a series of steps, and they show sweet,
fruity, and flower-like odors. Green tea, which is not fermented, has a fresh, grassy fla-
vor. Black tea, which is fully fermented, has a honey, flower-like flavor. Pu-erh tea, which
is post-microbially fermented, has a woody and stale flavor (Lv etal. 2015). Whether teas
produced from the same types of tea leaves coming from different tea trees show simi-
lar or different aroma characteristics has not been extensively studied. For finding the
similarity and differences of volatile and water-soluble compounds between Yunnan and
Fujian oolong tea, we compared them with those of other kinds of tea to decrease the
noises from the data of oolong teas.
In this study, the sensory evaluation, main water-soluble (i.e., caffeine, catechins, and
total polysaccharides) and volatile components of Yunnan oolong, Fujian oolong, green,
black, and Pu-erh teas were analyzed, and the aroma consistency of oolong teas made
from different tea tree leaves was discussed.
Methods
Tea samples
Five samples of Yunnan oolong tea were obtained from five typical production sites in
Yunnan Province, China and were numbered from YO1 to YO5. Five samples of Fujian
oolong tea were also obtained from five typical production sites in Fujian Province,
China and were numbered from FO1 to FO5. Ten samples of green tea were likewise
collected from Hunan, Yunnan, Sichuan, and Anhui provinces and were numbered from
GT1 to GT10, and ten samples of black tea were collected from Yunnan, Anhui, Fujian,
and Hunan provinces and were numbered from BT1 to BT10. Finally, 10 samples of Pu-
erh tea were collected from Yunnan Province, China and were numbered from CT1 to
CT10. In addition, all the tea samples were harvested in spring, 2015; and the varieties of
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Wang et al. SpringerPlus (2016) 5:576
them identified by National Centre for Pu-erh Tea Production Quality Supervision and
Inspection, Pu-erh, Yunnan, China.
Chemicals
e following chemicals and solvents were used: (+)-Catechin (C,99%), ()-epicat-
echin (EC,98 %), ()-epigallocatechin (EGC,95 %), ()-epigallocatechin gallate
(EGCG,95%), and ()-epicatechin gallate (ECG,98%) were obtained from Sigma-
Aldrich (St. Louis, MO, USA.). Methanol (HPLC grade,99.9%, Lichrosolv, Germany)
and acetic acid (HPLC grade,99.7%) were obtained from Fisher Scientific. All other
reagents and solvents were of analytical grade and used without further purification,
unless otherwise noted. All aqueous solutions were prepared with the use of newly dou-
ble-distilled water.
Sensory evaluation
According to the CNIS GB/T 14487-93, three grams of tea sample was extracted with
300mL of 85°C distilled water for 15min. e extracted tea infusion was filtered and
cooled to room temperature and then adjusted to a volume of 500mL. en the sensory
characteristics of the extracted tea infusions were evaluated by five panelists at Faculty
of Life Science and Technology, Kunming University of Science and Technology, based
on the color, taste and flavor of tea infusions.
Catechin andcaeine analysis
Samples weighing 0.2±0.001g were placed in extraction tubes (10mL). Five milliliters
of preheated 70% water/methanol extraction mixture was filled into each tube individu-
ally, incubated in water bath for 10min at 70°C, and vortexed for 5 and 10min, respec-
tively. e extracts were combined and made up to 10mL with cold methanol/water
extraction mixture.
e content and composition of catechins and caffeine in the extract were determined
with an HPLC system (2695; Waters Corp., MA, USA) equipped with a Waters Sunfire
C18 column (5, 4.6×250mm, 35°C) at 278nm. e measurement was adjusted as fol-
lows: flow rate: 1.0mL/min; injection volume: 10μL; mobile phase: A 98% methanol and
2% acetic acid, B 98% water and 2% acetic acid; gradient elution: 20–25% A, 0–1min;
25–45% A, 1–12min; 45–90% A, 12–14.3min; 90–20% A, 14.3–15min; maintained
for 5min. Concentrations of catechins and caffeine were quantified by their peak areas
against those of standards prepared from authentic compounds.
Determination oftotal polysaccharides
Total polysaccharides were measured according to the method described by Xi et al.
(2010). e dry, ground tea leaves (50g) were extracted with 400mL distilled water at
90°C in a water bath for 2h. After being filtered, the residue was extracted again with
500mL distilled water for another 2h. en, the extracts were centrifuged to remove
contaminants. e supernatant was concentrated via rotary evaporation and precipi-
tated with 95% ethanol. e tea extracts were measured with this method.
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Wang et al. SpringerPlus (2016) 5:576
HS‑SPME procedure
e HS-SPME parameters of the tea sample were validated and optimized in a previ-
ous study (Lv etal. 2014b). erefore, the same method and parameters were used in
the current study to extract the volatile components of the tea samples. Using the same
method is advantageous in tracing the change in aroma compounds during the pro-
duction of the tea sample and in facilitating a comprehensive comparison of the aroma
components among four different tea samples. A detailed explanation of the HS-SPME
parameters is as follows.
A total of 2.0g ground tea sample was placed in a 20mL sealed headspace vial with 5mL
distilled water, and the temperature of the headspace vial was kept at 80°C for 60min
with an electric hot plate. en, a 65 μm polydimethylsiloxane/divinylbenzene coating
fiber (Supelco Inc., Bellefonte, PA) was exposed to the sample headspace and retained for
60min. All volatile compounds absorbed on the SPME fiber were desorbed at the GC–MS
injector at 250°C for 3.5min and then immediately analyzed by GC–MS. After adsorp-
tion, SPME coating fiber was transferred to the GC injection port at 250°C for 30min.
GC–MS analysis
An HP 7890A GC instrument combined with an HP 5975C mass selective detec-
tor (MSD) quadrupole MS instrument (Agilent Technologies, Palo Alto, CA, USA)
was used for the GC–MS analysis. e capillary column utilized was HP-5MS
(30m×0.25mm×0.25μm film thickness) from Agilent technologies, and high-purity
helium (purity 99.999%) was used as carrier gas at a flow rate of 1mL/min. e injec-
tor and ion source temperatures were set at 250 and 200°C, respectively. Samples were
injected in splitless mode. e initial GC oven temperature was 50°C, held for 5min,
and then ramped at 3°C/min to 210°C, held for 3min, and finally programmed to
230°C at 15°C/min. e Agilent 5975C MS was operated in the electron impact mode
using ionization energy of 70eV with an ionization source temperature of 230°C and a
quadrupole set of 150°C. e acquisition mode was full scan (from 30 to 500m/z), and
the solvent delay time was 2.8min.
Compound identication
With the use of the MSD G1701EA E.02.00.493 chemical workstation data processing
system (Agilent Technologies, Palo Alto, CA, USA), peak identifications were made via
a search of the National Institute of Standards and Technology (NIST) 08.L MS data
library (Qiao etal. 2008; Schuh and Schieberle 2006). e relative percentage content of
the aroma components was determined by peak area normalization.
e relative proportions of the constituents were obtained by peak area normalization.
Quantitative results were obtained by using the method as follows:
Data analysis
Significant differences between four different types of tea samples for each of the aroma
compounds were determined by Duncan’s multiple range test analysis using SPSS sta-
tistical package (version 17.0 for Windows, SPSS, Inc., Chicago, IL, USA). PCA and CA
were performed with SIMCA-P software (version 12.0, Umetrics, Umea, Sweden).
Relative content
(%)=single constituent area
total area ×
100 %
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Wang et al. SpringerPlus (2016) 5:576
Results anddiscussion
Sensory evaluation
Sensory evaluation of extracted tea infusions was performed in this work. As shown in Fig.1,
the following scales were used to rank the intensity of these nine attributes: very strong-5.0,
strong-4.0, fairly strong-3.0, weak-2.0, very weak-1.0. e results showed that the sensory
quality of Yunnan and Fujian oolong teas both were flower-like flavor and sweet, fruity taste;
but Yunnan oolong tea infusion showed more bitterness and less sweet than Fujian oolong
tea; green tea infusions showed grassy flavor and fresh taste; Black tea has a fruity, flower-
like flavor and sweet, honey taste; and Pu-erh tea has a woody, stale flavor and the taste of
slight bitterness and astringency. In addition, Fig.2 showed the differences among the color
of Yunnan oolong tea, Fujian oolong tea and other kinds of tea infusions. e color of Pu-erh
tea infusion was darkest while that of Yunnan oolong tea infusion was lightest.
Analysis ofthe main water‑soluble components ofFujian oolong tea, Yunnan oolong tea,
green tea, black tea, andPu‑erh tea
Polysaccharides, caffeine, and catechins, which are highly soluble in water, in tea leaf
shoots play a significant role in tea quality (Willson and Clifford 1992). Table1 shows that
the caffeine, catechin, and total polysaccharide content of Yunnan and Fujian oolong teas
was different (P<0.05); green, black, and Pu-erh teas had a higher caffeine content than
oolong tea (P<0.05); green tea had the highest catechin content among the five types
Fig. 1 Spider diagram of the sensory evaluation
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Wang et al. SpringerPlus (2016) 5:576
of teas (P<0.05), whereas black tea had the highest polysaccharide content. After being
semi-fermented, most of the oolong teas, including the Yunnan and Fujian oolong teas,
had little catechin content, and their polysaccharide content decreased as well. Yunnan
oolong tea had the lowest polysaccharide content among the five types of teas (P<0.05).
Our results were consistent with Wang etal. (2000); Xi etal. (2010); Wang etal. (2011).
e findings indicated that Camellia sinensis var. sinensis and var. assamica of the oolong
tea samples, i.e., Fujian and Yunnan oolong teas, respectively, were naturally different.
Analysis ofthe volatile compounds ofFujian oolong tea, Yunnan oolong tea, green tea,
black tea, andPu‑erh tea
Table2 shows that a total of 92 aroma compounds were identified in all 40 tea samples.
No significant difference between the most volatile compounds of Yunnan oolong tea
Fig. 2 The shapes and tea soup color of different types of tea
Table 1 Total polysaccharides and catechins contents (mg g1) inYunnan oolong teas,
Fujian oolong tea, Green teas, Black teas, andPu-erh teas
EGC ()-epigallocatechin, C (+)-catechin, EC ()-epicatechin, EGCG ()-epigallocatechin gallate, ECG ()-epicatechin gallate
* For each parameter, dierent letters within a row indicate dierence between dierent types of tea with Duncan’s multiple
range test (P<0.05)
Compound Yunnan oolong
tea (n=5) Fujian oolong
tea (n=5) Green tea
(n=10) Black tea
(n=10) Pu‑erh tea
(n=10)
EGC 10.31 ± 2.54a*14.15 ± 3.80b 13.90 ± 5.51b 0.37 ± 0.20c 1.19 ± 0.24c
C 2.46 ± 0.94a 4.84 ± 1.12b 6.29 ± 2.36b 1.04 ± 0.69a 1.96 ± 0.41a
EC 2.15 ± 0.85a 4.29 ± 0.65b 5.82 ± 2.22c 1.38 ± 0.73a 1.36 ± 0.48a
EGCG 31.87 ± 8.35a 38.24 ± 8.75b 50.56 ± 8.04c 3.43 ± 1.02d 0.13 ± 0.08d
ECG 4.07 ± 0.69a 8.24 ± 2.68b 17.61 ± 3.39c 3.53 ± 1.40a 0.18 ± 0.16d
Total polysac-
charides 14.00 ± 2.41a 18.52 ± 1.53c 10.31 ± 1.50b 18.33 ± 2.47c 17.54 ± 1.73c
Caffeine 14.56 ± 3.27a 16.20 ± 5.48b 26.53 ± 7.65c 21.17 ± 2.72d 22.61 ± 5.8d
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Table 2 Volatile components andtheir relative contents inYunnan oolong teas, Fujian oolong tea, Green teas, Black teas, andPu-erh teas
No. Retention time Compound Yunnan oolong tea (n=5) Fujian oolong tea (n=5) Green tea (n=10) Black tea (n=10) Pu‑erh tea (n=10)
1 4.140 Hexanal 0.00a*0.00a 0.00a 0.23 ± 0.12b 0.00a
2 5.733 (E)-2-Hexenal 0.00a 0.00a 0.00a 0.1 ± 0.09b 0.00a
3 5.746 cis-3-Hexen-1-ol 0.00a 0.00a 0.00a 0.27 ± 0.23b 0.00a
4 6.260 cis-2-Hexen-1-ol 0.00a 0.00a 0.00a 0.08 ± 0.15a 0.00a
5 6.345 1-Pentanol 0.41 ± 0.67a 1.24 ± 1.01b 0.11 ± 0.17a 0.15 ± 0.17a 0.00a
6 6.741 1-Hexanol 0.18 ± 0.24b 0.33 ± 0.39b 0.00a 0.00a 0.00a
7 7.131 2-Heptanone 0.09 ± 0.13b 0.02 ± 0.05a 0.00a 0.00a 0.00a
8 7.579 2-Heptanol 0.17 ± 0.18b 0.15 ± 0.15ab 0.00a 0.10 ± 0.20ab 0.00a
9 9.989 Benzaldehyde 0.74 ± 0.87b 0.17 ± 0.16a 0.19 ± 0.04a 0.41 ± 0.17ab 0.18 ± 0.08a
10 11.051 1-Octen-3-ol 0.34 ± 0.57ab 0.96 ± 0.48c 0.76 ± 0.78bc 0.11 ± 0.24a 0.03 ± 0.05a
11 11.342 6-Methyl-5-hepten-2-one 0.00a 0.00a 0.25 ± 0.14b 0.00a 0.00a
12 11.599 2-Pentyl-furan 0.00a 0.00a 0.81 ± 0.40bc 1.37 ± 1.12c 0.18 ± 0.10ab
13 13.321 Benzyl alcohol 2.35 ± 1.43c 3.45 ± 0.53d 1.26 ± 0.87b 0.39 ± 0.36a 0.04 ± 0.06a
14 13.590 D-Limonene 1.51 ± 1.60c 1.2 ± 0.10bc 0.32 ± 0.16a 0.59 ± 0.58ab 0.02 ± 0.05a
15 14.049 Phenylacetaldehyde 0.00a 0.00a 0.00a 0.95 ± 0.51b 0.04 ± 0.07a
16 14.123 1H-Pyrrole-2-carboxaldehyde 0.00a 0.00a 0.00a 0.27 ± 0.29b 0.19 ± 0.18ab
17 14.413 Ocimene 0.57 ± 0.52b 0.37 ± 0.25ab 0.43 ± 0.2ab 0.55 ± 0.77b 0.00a
18 15.427 (E)-2-Octen-1-ol 0.00a 0.00a 0.35 ± 0.32b 0.00a 0.00a
19 15.569 Linalool oxide I 3.77 ± 1.44a 4.12 ± 0.83a 0.98 ± 0.57b 1.6 ± 0.85b 1.11 ± 0.64b
20 16.344 Linalool oxide II 4.61 ± 1.92a 4.49 ± 1.15a 2.10 ± 0.77b 3.71 ± 1.77a 2.17 ± 0.85b
21 17.097 Linalool 19.97 ± 2.73a 20.36 ± 1.54a 13.23 ± 4.59a 12.60 ± 14.78a 0.80 ± 0.69b
22 17.23 3,7-Dimethyl-1,5,7-octatriene-
3-ol 0.00a 0.00a 0.00a 1.11 ± 1.42b 0.00a
23 17.513 Phenylethyl alcohol 1.86 ± 1.53a 1.15 ± 1.10a 0.41 ± 0.58a 3.85 ± 6.04a 0.36 ± 0.29a
24 19.401 1,2-dimethoxy benzene 0.00a 0.00a 0.00a 0.00a 1.38 ± 0.41b
25 20.266 Linalool oxide III 0.28 ± 0.29ab 0.24 ± 0.11ab 0.00a 0.45 ± 0.45b 0.52 ± 0.29b
26 20.544 Linalool oxide IV 4.64 ± 2.52a 1.35 ± 0.88b 0.70 ± 0.43b 1.88 ± 1.10b 1.71 ± 0.98b
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Table 2 continued
No. Retention time Compound Yunnan oolong tea (n=5) Fujian oolong tea (n=5) Green tea (n=10) Black tea (n=10) Pu‑erh tea (n=10)
27 20.703 Naphthalene 1.07 ± 1.02a 0.96 ± 0.94a 0.42 ± 0.22ab 0.09 ± 0.13ab 0.51 ± 0.90a
28 21.302 α-Terpineol 2.14 ± 3.39ab 1.65 ± 1.22ab 2.82 ± 1.59b 0.38 ± 0.37a 1.60 ± 0.81ab
29 21.439 Methyl salicylate 2.27 ± 1.84bc 1.89 ± 1.28abc 0.83 ± 1.14ab 3.45 ± 2.00c 0.41 ± 0.31a
30 21.686 Safranal 0.94 ± 0.22a 0.47 ± 0.37b 0.34 ± 0.09b 0.11 ± 0.09c 0.15 ± 0.12c
31 21.85 Dodecane 0.00a 0.00a 2.39 ± 1.46b 0.17 ± 0.32a 0.05 ± 0.08a
32 22.262 Decanal 0.00a 0.00a 0.00a 0.12 ± 0.07a 0.27 ± 0.19b
33 22.672 β-Cyclocitral 0.00a 0.00a 0.63 ± 0.23ab 0.29 ± 0.26b 0.13 ± 0.10c
34 23.135 Nerol 0.91 ± 1.00bc 1.08 ± 1.06c 0.32 ± 0.13a 0.41 ± 0.21ab 0.02 ± 0.06a
35 23.824 3,4-Dimethoxytoluene 0.00a 0.00a 0.00a 0.00a 0.84 ± 0.79b
36 24.467 Geraniol 2.82 ± 2.23a 0.54 ± 0.40a 1.68 ± 0.55a 12.63 ± 7.26b 0.47 ± 0.27a
37 25.293 2-Phenyl-2-butenal 0.00a 0.00a 0.00a 0.38 ± 0.21b 0.00a
38 25.857 2-Methyl-naphthalene 0.00a 0.00a 0.36 ± 0.11c 0.06 ± 0.07a 0.22 ± 0.09b
39 26.004 Indole 0.58 ± 0.47a 0.76 ± 0.29a 0.04 ± 0.09b 0.02 ± 0.07b 0.00b
40 26.475 Tridecane 0.00a 0.00a 6.23 ± 3.66b 0.45 ± 1.07a 0.00a
41 26.578 1-Methylnaphthalene 0.00a 0.00a 0.00a 0.06 ± 0.11a 0.18 ± 0.12b
42 27.027 1,2,3-Trimethoxybenzene 0.00a 0.00a 0.34 ± 0.27a 0.00a 14.41 ± 5.48b
43 27.695 4-Ethyl-1,4-dimethoxybenzene 0.00a 0.00a 0.00a 0.00a 2.3 ± 1.31b
44 28.624 2,6-Dimethoxyphenol 0.47 ± 0.15a 0.79 ± 0.53b 0.35 ± 0.23a 0.24 ± 0.15a 0.31 ± 0.2a
45 29.840 1,2,4-Trimethoxybenzene 0.00a 0.00a 0.00a 0.00a 5.16 ± 2.85b
46 30.093 Damascenone 0.58 ± 0.79a 0.44 ± 0.25a 0.00b 0.21 ± 0.40ab 0.00b
47 30.239 cis-3-Hexen-1-yl Hexanoate 0.00a 0.00a 0.00a 0.46 ± 0.62b 0.00a
48 30.466 Hexyl hexanoate 0.00a 0.00a 0.00a 0.16 ± 0.14b 0.00a
49 30.705 cis-Jasmone 0.81 ± 0.99a 0.57 ± 0.17a 0.48 ± 0.38a 0.63 ± 0.31a 0.39 ± 0.18a
50 30.842 Tetradecane 0.00a 0.00a 1.10 ± 0.26c 0.41 ± 0.10b 0.41 ± 0.12b
51 31.202 1,3,5-Trimethoxybenzene 0.00a 0.00a 0.00a 0.00a 3.40 ± 2.78b
52 31.374 α-Calacorene 0.00a 0.00a 0.05 ± 0.10a 0.20a ± 0.26 0.8 ± 0.4b
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Table 2 continued
No. Retention time Compound Yunnan oolong tea (n=5) Fujian oolong tea (n=5) Green tea (n=10) Black tea (n=10) Pu‑erh tea (n=10)
53 31.51 β-Caryophyllene 2.81 ± 3.22a 3.08 ± 2.12a 0.54 ± 0.56b 0.06 ± 0.13b 0.00b
54 31.934 α-Ionone 0.81 ± 0.76ab 0.84 ± 0.52ab 1.35 ± 0.48b 0.53 ± 0.41a 0.82 ± 0.31ab
55 32.294 1,2-Benzopyrone 0.00a 0.00a 0.45 ± 0.13c 0.25 ± 0.24b 0.00a
56 32.568 4-(2,6,6-trimethyl-1-cyclohexen-
1-yl)butan-2-one 0.00a 0.00a 0.00a 0.03 ± 0.09a 0.14 ± 0.15b
57 32.645 1-Methoxynaphthalene 0.00a 0.00a 0.00a 0.00a 0.58 ± 0.29b
58 32.855 2-Methoxynaphthalene 0.00a 0.00a 0.00a 0.00a 0.71 ± 0.25b
59 32.979 1,2,3,4-Tetramethoxybenzene 0.00a 0.00a 0.00a 0.00a 0.93 ± 0.45b
60 33.039 Geranyl acetone 1.02 ± 1.19a 1.45 ± 0.71ab 2.27 ± 0.82b 1.12 ± 0.53a 1.51 ± 0.68ab
61 33.395 β-Ionone 1.40 ± 1.05b 2.65 ± 1.57c 0.07 ± 0.22a 0.47 ± 0.42a 0.00a
62 34.388 1-(2,6,6-trimethyl-3-cyclohexen-
1-yl)-2-buten-1-one 0.00a 0.00a 0.00a 0.15 ± 0.11a 2.91 ± 2.30b
63 34.358 (E)-β-Farnesene 3.93 ± 3.61a 3.49 ± 3.15a 5.34 ± 1.53a 3.35 ± 2.57a 2.67 ± 0.89a
64 34.705 Cocal 0.00a 0.00a 0.00a 0.19 ± 0.19b 0.00a
65 34.97 Pentadecane 1.55 ± 1.78a 1.75 ± 1.11a 0.68 ± 0.21b 0.52 ± 0.12b 0.6 ± 0.16b
66 35.012 Methyl isoeugenol 0.00a 0.00a 0.00a 0.00a 0.41 ± 0.30b
67 35.219 Dibenzofuran 0.00a 0.00a 0.75 ± 0.64b 0.31 ± 0.57ab 0.53 ± 0.35ab
68 35.313 α-Farnesene 0.00a 0.00a 1.13 ± 1.02b 1.11 ± 0.67b 0.32 ± 0.40a
69 35.925 Dihydroactinidiolide 3.81 ± 0.82ab 3.71 ± 0.29ab 6.46 ± 1.12c 2.50 ± 1.29a 4.34 ± 1.48b
70 37.467 Nerolidol 2.86 ± 3.28bc 4.33 ± 1.56c 0.29 ± 0.39a 3.66 ± 1.73c 1.17 ± 0.80ab
71 37.688 cis-3-Hexen-1-yl benzoate 0.00a 0.00a 0.00a 0.66 ± 0.63b 0.00a
72 37.758 Fluorene 0.00a 0.00a 1.07 ± 0.42a 0.14 ± 0.22b 0.70 ± 0.31c
73 38.79 Cedrol 0.00a 0.00a 0.91 ± 0.41b 0.64 ± 1.05ab 1.15 ± 0.87b
74 39.884 Hexadecane 0.53 ± 0.76a 0.83 ± 0.27ab 1.24 ± 0.65bc 0.97 ± 0.23ab 1.64 ± 0.66c
75 40.845 α-Cadinol 0.00a 0.00a 1.17 ± 0.20c 0.51 ± 0.34b 1.07 ± 0.14c
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Table 2 continued
No. Retention time Compound Yunnan oolong tea (n=5) Fujian oolong tea (n=5) Green tea (n=10) Black tea (n=10) Pu‑erh tea (n=10)
76 40.897 Methyl jasmonate 0.00a 0.00a 0.00a 0.16 ± 0.36a 0.00a
77 41.051 2,2,5,5-Tetra methylbiphenyl 0.00a 0.00a 0.00a 0.22 ± 0.21a 0.52 ± 0.39b
78 42.584 Heptadecane 0.91 ± 0.95ab 0.36 ± 0.28a 1.19 ± 0.76ab 0.70 ± 0.46ab 1.44 ± 0.87b
79 42.811 2,6,10,14-Tetramethyl pentade-
cane 0.00a 0.00a 2.53 ± 1.44c 1.23 ± 0.52b 2.27 ± 1.28bc
80 44.879 Anthracene 0.00a 0.00a 1.17 ± 0.78b 0.88 ± 1.28a 1.39 ± 0.48b
81 46.099 Octadecane 0.84 ± 0.67ab 1.25 ± 0.20b 0.79 ± 0.55ab 0.36 ± 0.26a 1.26 ± 1.01b
82 46.425 2,6,10,14-Tetramethyl hexade-
cane 0.00a 0.00a 0.61 ± 0.56a 0.49 ± 0.41a 1.44 ± 1.02b
83 47.461 Caffeine 4.27 ± 2.15a 3.59 ± 1.27a 4.44 ± 3.62a 4.50 ± 2.55a 3.88 ± 2.29a
84 47.645 Phytone 2.44 ± 1.51a 2.38 ± 1.58a 3.68 ± 1.47a 3.18 ± 4.64a 3.86 ± 1.83a
85 50.021 Farnesyl acetone 1.49 ± 1.40a 2.15 ± 0.20a 3.04 ± 5.18a 0.18 ± 0.23a 0.49 ± 0.44a
86 50.33 Isophytol 0.45 ± 0.47a 0.31 ± 0.50a 0.16 ± 0.28a 0.17 ± 0.14a 1.25 ± 0.60b
87 51.006 Hexadecanoic acid methyl ester 3.08 ± 1.16a 3.3 ± 0.80a 0.53 ± 0.82c 1.41 ± 0.89b 0.54 ± 0.19c
88 51.657 Hexadecanoic acid 2.25 ± 2.44a 2.44 ± 2.09a 2.36 ± 1.90a 4.7 ± 5.02a 9.05 ± 4.07b
89 52.877 Eicosane 0.00a 0.00a 0.00a 0.00a 0.24 ± 0.23b
90 55.562 Methyl linoleate 0.52 ± 0.49a 0.39 ± 0.25ab 0.19 ± 0.23bc 0.32 ± 0.28abc 0.05 ± 0.11c
91 55.759 Methyl linolenate 0.58 ± 0.55a 0.92 ± 0.61a 0.64 ± 0.63a 0.49 ± 0.38a 0.41 ± 0.31a
92 56.192 Phytol 6.86 ± 2.32a 6.67 ± 2.47a 4.00 ± 3.40ab 4.23 ± 3.53ab 2.10 ± 1.86b
* For each parameter, dierent letters within a row indicate dierence between dierent types of tea with Duncan’s multiple range test (P<0.05)
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and Fujian oolong tea was observed (P>0.05). To differentiate oolong tea from other
types of teas, 1-hexanol content served as a valuable index (P<0.05). Compared with
those in other types of teas, benzylalcohol, indole, safranal, linalool oxides, β-ionone,
and hexadecanoic acid methyl ester were the volatile compounds detected in most of
the oolong tea samples (Table2). ese compounds are possibly principal contributors
to the fragrant flowery aroma of oolong tea. eir abundant concentrations in oolong
tea might be formed during tea manufacture, in which the hydrolysis of their glycosidase
and primeverosides by β-glucosidase is intensive (Wang etal. 2001). However, some
differences were still observed in the volatile compound content of Yunnan and Fujian
oolong teas. e 1-Pentanol and 1-octen-3-ol content of Fujian oolong tea was higher
than that of Yunnan oolong tea (P<0.05), whereas the benzaldehyde content of Yunnan
oolong tea was higher than that of Fujian oolong tea. ese subtle differences should be
related to the natural differences of the tea leaves used, as observed in the water-soluble
components. Because the most volatile compounds are transformed during fermenta-
tion or processing, hypothesizing that these minor differences can mostly be eliminated
by the adjustment of processing conditions is reasonable. Generally, the fermentation
degree of oolong tea is between that of green and black tea. erefore, more complicated
patterns of aroma flavors can be observed in semi-fermented oolong tea than in unfer-
mented green or fully fermented black tea.
CA can be used to show the natural groups that exist in a data set on the basis of the
information provided by the measured variables (Chen etal. 2008; Wu etal. 2012). All
percentage quantitative data of the 92 volatile compounds were used to calculate the
CA model. e similarity or diversity between different samples (objects) is usually rep-
resented in a dendrogram for ease of explanation. e objects in the same group are
similar to one another, and they are different from the objects in other groups. Figure3
shows that distinguishing Yunnan oolong tea (YO1–YO5) from Fujian oolong tea (FO1–
FO5) is difficult; on the other hand, oolong tea (YO1–YO5 and FO1–FO5) and other
types of teas (GT1–GT10, BT1–BT10, and PT1–PT10) were clearly different from one
another. Oolong tea (YT1–YT5 and FT1–FT5) was clustered more closely with the black
Fig. 3 Cluster analysis (CA) dendrogram of 40 tea samples
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Wang et al. SpringerPlus (2016) 5:576
tea (BT1–BT10) because they are processed with a fermentation step, although oolong
tea was semi-fermented. Finally, the following four main clusters were observed: the first
one was composed of ten Pu-erh teas; the second one, ten green teas; the third one, ten
oolong teas (five Yunnan oolong teas and five Fujian oolong teas but mixed together);
and the fourth one, ten black teas.
PCA is an effective way to discriminate between data observed (Ivosev etal. 2008). It
also involves a linear transformation of multiple variables into a low-dimensional space
that retains the maximum amount of information about the variables (Ma etal. 2013;
Wu etal. 2013). Generally, the score plot provides a visual determination of similarity
among the samples. PCA (Fig.4) was conducted with the use of the same data as those
used in the CA model. Figure4 shows that the score plot in the first two principal com-
ponents (PC1 and PC2) represents 71.43% of the total variability. e same figure shows
that oolong teas (including five Yunnan oolong teas and five Fujian oolong teas) resem-
bled one another closely and were clearly distinguished from the other types of teas in
the PCA model; oolong tea was closer to black tea than to the other types of teas. ese
PCA results were mostly consistent with the results shown in Table2. e CA and PCA
results also suggest that the volatile chemical compounds of the teas analyzed by fully
automatic HS-SPME can be used for quality evaluation and control.
e contributions of all 92 aroma compounds to the PCA results are shown in Fig.5.
e variables that explained maximum variance in the data had high contributions and
were considered important in discriminating samples between oolong tea and other
types of teas. Benzylalcohol (V13), linalool oxides (V19, V20, V25, and V26), safranal
(V30), indole (V39), β-ionone (V61), and hexadecanoic acid methyl ester (V87), which
contributed to the fruity and flower-like aroma, had high positive values in oolong tea
and were thought to enhance their aroma flavor (Kuo etal. 2011). ese volatile com-
pounds in oolong tea reached their highest levels during semi-fermentation (Wang etal.
2001). Fermentation was found to lead to the loss of grassy or green flavors and the
Fig. 4 Principal component analysis (PCA) score derived from 92 volatile compounds of 40 tea samples: YO
indicated by black color represents Yunnan oolong teas, FO indicated by red color represents Fujian oolong
teas, GT indicated by blue color represents green teas, BT indicated by green color represents black teas, and
PT indicated by yellow color represents Pu-erh teas
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Wang et al. SpringerPlus (2016) 5:576
formation of fruity and other fermented characters (Wang etal. 2008). Some nonalco-
holic volatile compounds, such as benzylalcohol, safranal, and hexadecanoic acid methyl
ester, were found to be transformed to glycosidically bound forms during fermentation
in oolong tea (Guo etal. 1998; Yang etal. 2009). Geranyl pyrophosphate was the pre-
cursor for monoterpene alcohols, such as linalool. Some specific terpene synthases are
involved in the biosynthesis of volatile monoterpene alcohols, which have been iden-
tified and validated in many plants (Creelman and Muleet 1995). Linalool oxide was
synthesized from linalool by the possible synthesis pathway of monoterpenoids in tea.
And the benzylalcohol in oolong tea was found to be related to the Ehrlich pathway that
occurs in fermentation (Bode and Dong 2003). In addition, the tea-derived enzyme in
oolong tea plants cleaves the 9,10 (910)-double bonds of arotenoids and long-chained
apocarotenoids to yield β-ionone (Felfe etal. 2011). is result was also mostly con-
sistent with the typical aroma compounds of oolong tea shown in Table2. Because the
volatile compounds were influenced by biological and chemical transformations dur-
ing cultivation and processing, we can conclude that these typical aroma compounds,
which made oolong tea different from other types of teas, were largely influenced by the
semi-fermentation step. Prior to this step, the bruising step breaks the cell membrane
and eventually facilitates the mixture of precursors with biological enzymes. Hereafter,
the most significant changes are the rapid conversions and transformations of the pre-
cursors to benzylalcohol, indole, safranal, linalool oxides, β-ionone, and hexadecanoic
acid methyl ester, mostly by enzymatic catalysis and chemical processes. erefore, fer-
mentation intensity influences the quantity of most tea volatiles during the manufactur-
ing process of green, oolong and black tea; and because of the distinctive processes of
oolong tea, its aroma characteristics are different from the unfermented green or fully
fermented black tea (Baldermann etal. 2014).
In summary, our results suggested that the aroma characteristics of oolong tea, which
are either Yunnan oolong tea (Camellia sinensis var. assamica) or Fujian oolong tea
(Camellia sinensis var. sinensis), were mostly consistent compared with those of the
Fig. 5 Coefficient plot related to the contribution of 92 volatile compounds to the principal component
analysis (PCA) results. The number (No.) of volatile compounds are consistent with that of Table 2
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Wang et al. SpringerPlus (2016) 5:576
other three types of teas (green, black, and Pu-erh tea). ese findings indicated that
although the raw materials, cultivation measures used and the environment factors
involved in tea production influence water-soluble and aroma components, processing
technology plays a crucial role in the formation of tea aroma. Further investigation will
focus on the influence of other factors (geographic characteristics, cultivars, etc.), par-
ticularly each processing step, on final aroma characteristics in the proposal of guide-
lines for the quality control of tea products.
Conclusion
is work reported for the first time that the same types of teas made from different tea
tree leaves but the same processing technology showed similar aroma flavor. Our results
demonstrated that the sensory evaluation and main water-soluble components, i.e., caf-
feine, catechins, and total polysaccharides, of Yunnan oolong tea were different from
those of Fujian oolong tea, but no significant difference was observed between their
aroma characteristics, as shown in the PCA and CA analyses. e PCA results showed
that benzylalcohol, indole, safranal, linalool oxides, β-ionone, and hexadecanoic acid
methyl ester strongly contributed to the aroma flavor of oolong tea compared to the case
of the green, black, and Pu-erh teas. Although the raw materials, cultivation measures
used and the environment factors involved in tea production influence water-soluble
and aroma components among different kinds of teas, processing technique for oolong
teas from different tea trees, especially the semi-fermentation process, is the main driver
of tea aroma characteristics.
Authors’ contributions
CW and SL conceived and designed the experiments; CW, YW, XG, JL, WZ performed the experiments; WC and SL
analyzed the data; QM contributed reagents/materials/analysis tools; CW and SL wrote the paper. All authors read and
approved the final manuscript.
Author details
1 Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, Yunnan,
People’s Republic of China. 2 Kunming Grain & Oil and Feed Product Quality Inspection Center, Kunming 650118, Yunnan,
People’s Republic of China.
Acknowledgements
We are grateful to Donghua Jiang and Zhenggang Luo (National Centre for Pu-erh Tea Production Quality Supervi-
sion and Inspection, Pu-erh, Yunnan, China) for their technical assistance with samples identification. This work was
supported by the National Natural Science Foundation of China (No. 31460228) and scientific research funds in Yunnan
province Department of Education (No. 2014Y089).
Competing interests
The authors declare that they have no competing interests.
Received: 22 December 2015 Accepted: 25 April 2016
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... Y. Guo, C. T. Ho, W. Schwab, et al., 2021), growing environment (C. Wang, S. D. Lv, Y. S. Wu, et al., 2016), processing methods, storage time (X. M. Yang, Y. L. Liu, L. H. Mu, et al., 2018), and brewing conditions. ...
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The effects of different brewing water samples, including natural drinking water (NDW), pure water (PW), mineral water (MW), distilled water (DW), and tap water (TW) on flavor and quality of green tea infusion were investigated. The results showed the dissolution rate of mineral substances varied greatly depend on the type of water used. Notably, the tea infusion brewed with MW showed the highest taste response and darker but higher brightness in color. Furthermore, the content of volatile compounds was highest in tea infusion brewed with NDW and lowest in tea infusion brewed with MW. The mineral substances content and pH were the main factors affecting volatile compounds in green tea infusion. Thereinto, Ca2+ and Fe3+ remarkably affected the content of alcohols and aldehydes in volatile compounds. These results suggested that water with a neutral pH value and lower mineral substance content is more conducive for brewing green tea.
... GM1 was mainly clustered with Japanese matcha of Class I. Among the functional characteristic components, hexadecanol acid was reported to contribute significantly to the unique aroma of oolong tea (65), and 1-hexadecanol constitutes the aroma quality of white tea (66). GM1, GM2 and M-GS have similar aroma characteristics to the matcha of Class II, and among the substances that are positively correlated with their aroma quality, 2, 6-nonadienal, (E,Z)-(green, fatty, dry, cucumber), 4-heptenal, (Z)-(green), 2, 4-heptadien-1-ol, (E,E)-(fatty, green, fruity), p-cresol (phenolic, narcissus, animal, mimosa), pyrazine, 2-ethyl-3, 5-dimethyl-(nutty, burnt, almond, coffee) and other substances have been reported as key aroma components in Japanese matcha tea (11). ...
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... Furthermore, the content of aldehydes (pentanal, crotonaldehyde) in low grade tobacco leaves after microbial treatment was significantly reduced, which often caused smoking irritation (Chen, 2013). PCA has been widely applied in the analysis of main aroma components in food industry (Wang et al., 2016;. By PCA, it was concluded that acetic acid, acetoin, 1-octen-3-one, and 3-methylindole are the most important compounds that lead to the difference between mild cheddar cheese and other medium and mature cheddar cheese . ...
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... HS-SPME can integrate the concentration, extraction, and introduction in a single step. Combing HS-SPME with GC-MS is employed to determine the volatile components in different plants like tea samples [22]. In the immersion SPME sampling technique, the fiber is directly placed into a liquid sample and the compounds of interest absorb/ adsorb to the fiber coating. ...
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There is a huge demand for brewing water in tea consumption, and the sensory flavor of tea infusion is significantly affected by the water used for brewing. To investigate the impact of brewing water on the aroma of tea infusions made from Camelia senensis, the three tea infusions of green, oolong and black tea brewed by six different drinking waters were analyzed by sensory evaluation, solid-phase microextraction, gas chromatography-mass spectrometry, and chemometrics. Brewing water with high pH values (>8.10) and high TDS content (>140 ppm) resulted in a lower overall aroma acceptability for tea infusion, where HCO3-, Ca2+ and Mg2+ were key influencing ions. A total of 86, 106, and 131 volatiles were identified in green, oolong and black tea infusions, respectively, which were strongly influenced by six different brands of waters. Decanal, dimethyl sulfide, β-ionone and linalool were potent volatiles in tea aroma changes caused by brewing water.
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Book
Tea is a unique crop and, incidentally, a very interesting and attractive one. The tea bush, its cultivation and harvesting do not fit into any typical cropping pattern. Moreover, its processing and marketing are specific to tea. Thus the Tea Industry stands apart and constitutes a self contained entity. This is reflected in the title given to this book, Tea: Cultivation to consumption, and its treatment of the subject. The book is logically planned - starting with the plant itself and finishing with the traditional'cuppa'. Every aspect of tea production is covered, inevitably some in greater detail than others. However, it gives an authentic and comprehensive picture of the tea industry. The text deals in detail with cultural practices and research, where desirable, on a regional basis. The technology of tea cultivation and processing has been developed within the industry, aided by applied research which was largely financed by the tea companies themselves. This contributed to a technically competent industry but tended to bypass the more academic and fundamental investigations which might bring future rewards. The sponsorship of research has now widened and the range and depth of tea research has increased accordingly. The editors and authors of this book have played their part in these recent developments which are well reported in the book.
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Many dark-colored fruit juices, rich in anthocyanins, are thought to be important for human health. Joboticaba (Myrciaria cauliflora) fruits, native to Brazil, have phenolics including anthocyanins, and are processed into juice and other products. The phenolic constituents in the fruits of jaboticaba were studied by high-performance liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry. Twenty-two compounds were identified or tentatively determined by detailed analysis of their mass spectral fragmentation patterns; eleven compounds including seven gallotannins, two ellagic acid derivatives, syringin and its glucoside were detected for the first time in the fruit. The compositional differences among the fruit extracts and their commercial products were also compared by principal component analysis; two anthocyanins, delphinidin 3-O-glucoside and cyanidin-3-O-glucoside, as well as two depsides, jaboticabin and 2-O-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxyphenylacetic acid present in the fruit extracts were not detected unexpectedly in commercial jaboticaba juice or jam. Therefore stability of anthocyanins in jaboticaba fresh fruits and products has been compared directly with that of other dark-colored fruit products made from blueberry and grape, and the same trend of decreasing amounts of anthocyanins was observed in all tested products.
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Tea is one of the most popular beverages consumed in the world and has been demonstrated to have anti-cancer activity in animal models. Research findings suggest that the polyphenolic compounds, (-)-epigallocatechin-3-gailate found primarily in green tea, and theaflavin-3,3'-digallate, a major component of black tea, are the two most effective anti-cancer factors found in tea. Several mechanisms to explain the chemopreventive effects of tea have been presented but others and we suggest that tea components target specific cell-signaling pathways responsible for regulating cellular proliferation or apoptosis. These pathways include signal transduction pathways leading to activator protein-1 (AP-1) and/or nuclear factor kappa B (NF-kappaB). AP-1 and NF-kappaB are transcription factors that are known to be extremely important in tumor promoter-induced cell transformation and tumor promotion, and both are influenced differentially by the MAP kinase pathways. The purpose of this brief review is to present recent research data from other and our laboratory focusing on the tea-induced cellular signal transduction events associated with the MAP kinase, AP-1, and NF-kappaB pathways.
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With the aim to study the volatile aroma component of dark teas from five different production regions (Yunnan, Hunan, Sichuan, Guangxi, and Hubei) in China, the fully automatic headspace solid-phase microextraction (HS-SPME) method was constructed for extracting the volatiles and gas chromatography-mass spectrometry (GC-MS) coupled with retention index (RI) of the volatiles were used to determine the volatiles variety in dark tea samples. The result showed that 105 aroma constituents were determined in five dark teas, mainly including alcohols, ketones, hydrocarbons, and methoxy-phenolic compounds, etc. Among which the methoxy-phenolic compounds were the most abundant components in the Pu-erh ripe tea, mainly including 1,2,3-trimethoxybenzene, 1,2,3-trimethoxy-5-methylbenzene, and 1,2,4-trimethoxy benzene. Ketones were the most abundant components in the Heimao tea and Yaan dark tea, mainly including β-ionone, geranyl acetone, and 6,10,14-trimethyl-2-pentadecanone. While the hydrocarbons were the most abundant components in the Liubao tea and Qingzhuan tea, mainly including 2,6,10,14-tetramethyl-pentadecane, 2,6,10,14-tetramethyl-hexadecane, and heptadecane, etc. In comparison, there were remarkable differences in flavor and aroma composition of the five types of dark tea, which may be related to the different species or subspecies, growing region and processing technology.