ArticlePDF Available

The Powdering Process with a Set of Ceramic Mills for Green Tea Promoted Catechin Extraction and the ROS Inhibition Effect

Authors:

Abstract and Figures

For serving green tea, there are two prominent methods: steeping the leaf or the powdered leaf (matcha style) in hot water. The purpose of the present study was to reveal chemical and functional differences before and after the powdering process of green tea leaf, since powdered green tea may contribute to expanding the functionality because of the different ingesting style. In this study, we revealed that the powdering process with a ceramic mill and stirring in hot water increased the average extracted concentration of epigallocatechin gallate (EGCG) by more than three times compared with that in leaf tea using high-performance liquid chromatography (HPLC) and liquid chromatography–tandem mass Spectrometry (LC-MS/MS) analyses. Moreover, powdered green tea has a higher inhibition effect of reactive oxygen species (ROS) production in vitro compared with the same amount of leaf tea. Our data suggest that powdered green tea might have a different function from leaf tea due to the higher catechin contents and particles.
Content may be subject to copyright.
molecules
Article
The Powdering Process with a Set of Ceramic Mills
for Green Tea Promoted Catechin Extraction and the
ROS Inhibition Effect
Kouki Fujioka
1,
*, Takeo Iwamoto
1
, Hidekazu Shima
2
, Keiko Tomaru
1
, Hideki Saito
1
,
Masaki Ohtsuka
2
, Akihiro Yoshidome
2
, Yuri Kawamura
2
and Yoshinobu Manome
1
1
Division of Molecular Cell Biology, Core Research Facilities for Basic Science, The Jikei University
School of Medicine, Tokyo 105-8461, Japan; tmiwamoto@jikei.ac.jp (T.I.); tomaru@jikei.ac.jp (K.T.);
h-saito@jikei.ac.jp (H.S.); manome@jikei.ac.jp (Y.M.)
2
Health and Environment Systems Division, Consumer Electronics Company, Sharp Corporation,
Osaka 581-8585, Japan; shima.hidekazu@sharp.co.jp (H.S.); ohtsuka.masaki@sharp.co.jp (M.O.);
yoshidome.akihiro@sharp.co.jp (A.Y.); tynkerbell1218@hotmail.com (Y.K.)
* Correspondence: kfujioka@jikei.ac.jp; Tel.: +81-3-3433-1111
Academic Editors: Rafael Llorach and Pedro Mena
Received: 3 February 2016; Accepted: 1 April 2016; Published: 11 April 2016
Abstract:
For serving green tea, there are two prominent methods: steeping the leaf or the powdered
leaf (matcha style) in hot water. The purpose of the present study was to reveal chemical and
functional differences before and after the powdering process of green tea leaf, since powdered green
tea may contribute to expanding the functionality because of the different ingesting style. In this
study, we revealed that the powdering process with a ceramic mill and stirring in hot water increased
the average extracted concentration of epigallocatechin gallate (EGCG) by more than three times
compared with that in leaf tea using high-performance liquid chromatography (HPLC) and liquid
chromatography–tandem mass Spectrometry (LC-MS/MS) analyses. Moreover, powdered green tea
has a higher inhibition effect of reactive oxygen species (ROS) production
in vitro
compared with the
same amount of leaf tea. Our data suggest that powdered green tea might have a different function
from leaf tea due to the higher catechin contents and particles.
Keywords: green tea; matcha; catechin; polyphenol; powdering process; mill; ROS
1. Introduction
The health benefits of green tea consumption have been reported to include: cancer inhibition [
1
,
2
],
allergy relief effects [
3
], cognitive dysfunction [
4
], and preventive effects on metabolic syndrome [
5
,
6
].
In a large epidemiological study, which was based on a follow-up investigation of 82,369 Japanese
people for 13 years, green tea consumption also showed positive effects such as lowering the risk of
cardiovascular diseases and stroke [
7
]. Moreover, another follow-up study of 90,914 Japanese people
for 18.7 years suggested that the consumption of green tea reduces the risk of total mortality and
three leading causes of death: heart disease, cerebrovascular disease, and respiratory disease [
8
].
This evidence of health benefits should attract the attention of health-conscious people.
There are two prominent methods for serving green tea. The general serving method consists of
steeping the leaves in hot water and filtering them through a tea strainer. In contrast, in traditional
Japanese tea ceremony, fine powdered green tealeaves (matcha) are foamed with a tea whisk in hot
water. Ingestion of matcha likely allows for the introduction of a large amount of tealeaf components
into our body.
Matcha is typically produced from shade-grown green tealeaves that are steamed, dried, and then
ground with a set of millstones. According to Sawamura et al. [
9
], it is unknown when millstones came
Molecules 2016, 21, 474; doi:10.3390/molecules21040474 www.mdpi.com/journal/molecules
Molecules 2016, 21, 474 2 of 12
into use. However, since ancient documents have reported the use of millstones for tea leaves in the
11th century in China [
9
,
10
] and in the 14th century in Japan [
9
,
11
], it is likely that the ingestion of
powdered green tealeaves may have been a habit for a long time.
Major components of matcha [
12
] are catechins, which are known for their anti-oxidant
activity [
13
], amino acids, and saponins, which contribute to the foaming property of matcha [
14
].
Using high-performance liquid chromatography (HPLC) analysis, Saijo et al. [
15
] showed that catechins
make up 4.92% of the dry weight of matcha. In addition, liquid chromatography–mass spectrometry
(LC-MS) quantification of catechins in commercially available green tea by Goto et al. [
16
] showed
that epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG), and epigallocatechin gallate
(EGCG) were the four main types of catechin present in matcha with an average content of 11.19%,
while the caffeine content was 3.77%. Moreover, EGCG has predominant functions as a highly
anti-oxidant compound [17,18] among green tea catechins.
Studies on the physical properties of matcha have revealed differences in particle sizes, shapes,
and foaming properties as the result of diverse powdering methods. Onishi et al. [
19
] reported
matcha particles of several micrometers by using electron microscopy, while Sawamura et al. reported
median diameters of 15–20
µ
m (millstone and ball mill), or
ď
5
µ
m (jet mill) using laser diffraction
analysis [20,21].
Although there are many reports on the chemical and physical properties of powdered green tea,
changes in its properties before and after powdering process using the same tealeaves have not been
revealed. Since changes in the powdering process may alter the chemical components and functionality
of the green tea, thus contributing to expand its health-promoting benefits, we investigated the
differences in physical property, catechin concentration, and reactive oxygen species (ROS) inhibitory
effect of green tea prepared from whole leaves or powdered leaves.
2. Results
2.1. Particle Appearance in Different Powdering Methods
The physical properties of whole green tealeaves and those powdered using three different
methods were evaluated by electron microscopy (Figure 1). In the case of the tealeaf, the tissue
structure of the plant was partially maintained, and small granular particles of 1–20
µ
m were observed
around the tealeaves. In contrast, when powdered with a ceramic mill, ball mill, or mixer, many leaves
were miniaturized into particles of less than 100
µ
m. Furthermore, the use of a ceramic mill, which is
characterized by a strong shearing force [
20
], resulted in particles with torn shapes in comparison to
other methods.
Next, the whole and powdered tealeaves were brewed in hot water and observed with multifocal
optical microscope in an automated cell counter. Many black particles were observed when powdered
with the ceramic mill, ball mill, and mixer (Figure 2a). In contrast, regular tea from steeped tealeaves
showed fewer black particles, although faint grey micro particles were also observed. The number of
particles in a 4-mm
2
field (Figure 2a) was determined with image analysis software (WinRoof 2013)
as 2910–3014 for regular tea, including faint gray micro particles; 14,760–15,767 for the ceramic mill;
16,135–18,583 for the ball mill; and 13,374–18,090 for the mixer. In addition, the particle size distribution
showed that median particle size was 49.20
µ
m for normal green tea, 15.01
µ
m for the leaves powdered
with the ceramic mill, 23.03
µ
m for those treated with the ball mill, and 31.85
µ
m for those processed
with the mixer (Figure 2b).
Molecules 2016, 21, 474 3 of 12
Molecules 2016, 21, 474 3 of 12
Figure 1. Appearance of green tea leaf and powder produced with different powdering method. Left
panel (color) shows the photograph of green leaf and the powders produced with indicated
powdering process. Right panel (monochrome) shows the images of leaf and the powders using the
scanning electron microscope at indicated magnification.
Figure 2. Particle appearance in the green tea liquid and size distribution of tea particles: (a)
multifocal microscope images of particles in regular tea and the powdered tea produced by indicated
powdering process; and (b) particle size distributions of the teas measured with laser diffraction
particle size analyzer. Regular: Regular leaf tea.
2.2. Catechin Contents of Powdered Tea and Leaf Tea
Based on the particle size differences and characteristic shapes, we compared the release of
components from the leaf tea (Leaf) and the powdered tea produced with the ceramic mill (Powder).
The concentration of polyphenol, which is the major green tea component, was measured using
Folin–Denis method (Table 1). In this experiment, three types of tea were prepared: (1) the regular
brewing method (Regular); (2) brewing powder with hot water and stirring for one minute with a
Figure 1.
Appearance of green tea leaf and powder produced with different powdering method.
Left panel (color) shows the photograph of green leaf and the powders produced with indicated
powdering process. Right panel (monochrome) shows the images of leaf and the powders using the
scanning electron microscope at indicated magnification.
Molecules 2016, 21, 474 3 of 12
Figure 1. Appearance of green tea leaf and powder produced with different powdering method. Left
panel (color) shows the photograph of green leaf and the powders produced with indicated
powdering process. Right panel (monochrome) shows the images of leaf and the powders using the
scanning electron microscope at indicated magnification.
Figure 2. Particle appearance in the green tea liquid and size distribution of tea particles: (a)
multifocal microscope images of particles in regular tea and the powdered tea produced by indicated
powdering process; and (b) particle size distributions of the teas measured with laser diffraction
particle size analyzer. Regular: Regular leaf tea.
2.2. Catechin Contents of Powdered Tea and Leaf Tea
Based on the particle size differences and characteristic shapes, we compared the release of
components from the leaf tea (Leaf) and the powdered tea produced with the ceramic mill (Powder).
The concentration of polyphenol, which is the major green tea component, was measured using
Folin–Denis method (Table 1). In this experiment, three types of tea were prepared: (1) the regular
brewing method (Regular); (2) brewing powder with hot water and stirring for one minute with a
Figure 2.
Particle appearance in the green tea liquid and size distribution of tea particles: (
a
) multifocal
microscope images of particles in regular tea and the powdered tea produced by indicated powdering
process; and (
b
) particle size distributions of the teas measured with laser diffraction particle size
analyzer. Regular: Regular leaf tea.
Molecules 2016, 21, 474 4 of 12
2.2. Catechin Contents of Powdered Tea and Leaf Tea
Based on the particle size differences and characteristic shapes, we compared the release of
components from the leaf tea (Leaf) and the powdered tea produced with the ceramic mill (Powder).
The concentration of polyphenol, which is the major green tea component, was measured using
Folin–Denis method (Table 1). In this experiment, three types of tea were prepared: (1) the regular
brewing method (Regular); (2) brewing powder with hot water and stirring for one minute with a
stirrer to mimic a tea ceremony method (Powder and Strong Powder); and (3) brewing the leaves with
hot water and stirring for one minute as the control (Leaf and Strong Leaf). Concentration of total
polyphenol was higher in the Strong Powder and Strong Leaf tea than in the Regular tea. Moreover,
compared to the Leaf teas, the Powder teas had a higher total polyphenol concentration at same
leaf/powder contents. These results indicate that polyphenol extraction is accelerated by the grinding
process with the ceramic mill and the stirring process at brewing.
Table 1.
Total polyphenol, catechin, and caffeine concentration in green teas by Folin–Denis assay and
high-performance liquid chromatography (HPLC) analysis.
Leaf/Powder
Contents
(g/80 mL)
Total
Polyphenol
(µg CE/mL)
EC (µg/mL) ECG (µg/mL) EGC (µg/mL)
EGCG
(µg/mL)
Caffeine
(µg/mL)
Regular 2.00 1275.5 ˘ 13.91
a
94.5 ˘ 2.45
a
31.4 ˘ 3.55
a
354.8 ˘ 6.9
a
195.6 ˘ 3.77
a
191.1 ˘ 1.85
a
Powder 0.36
1121.1 ˘ 28.96
b
56.3 ˘ 0.42
b
35.7 ˘ 5.69
a
191.3 ˘ 8.75
b
210.6
˘
23.41
a
121.5 ˘ 1.51
b
Leaf 0.36 373.0 ˘ 7.20
c
37.0 ˘ 0.91
c
18.1 ˘ 1.40
a
38.8 ˘ 3.14
c
57.9 ˘ 1.96
b
77.8 ˘ 0.64
c
Strong
Powder
0.96
3055.1 ˘ 26.35
d
131.1 ˘ 1.27
d
98.0 ˘ 21.22
b
513.7 ˘ 1.74
d
615.1
˘
88.36
c
311.9 ˘ 4.32
d
Strong Leaf 0.96 1890.9 ˘ 11.24
e
136.0 ˘ 0.28
e
33.3 ˘ 7.67
a
501.2 ˘ 5.84
d
200.1 ˘ 6.94
a
244.0 ˘ 1.88
e
Retention
Time (min)
20.2 30.5 13.0 22.0 10.6
CE: Catechin equivalents. Retention time was calculated by the average of five measurements of
standard chemicals. All concentration values represent the mean
˘
standard deviation (SD) of three
measurements. In each column, means with the different superscript letter are significantly different at 5% level
(Bonferroni/Dunn method). Regular: Leaf tea steeped without stirring. Powder, Strong Powder: Powdered tea
steeped with stirring. Leaf, Strong Leaf: Leaf tea steeped with stirring.
The concentrations of the four major catechins (EC, EGC, ECG, and EGCG) and caffeine
component in the teas were measured using HPLC (Table 1). ECG, EGCG and caffeine were detected
at significantly higher concentrations in Strong Powder tea. In addition, both Powder teas showed
the significantly higher concentrations of EGCG and caffeine and showed the tendency of higher
concentration of ECG than Leaf teas at the same contents of powder/leaf. These results indicate that
powdering process with the ceramic mill and stirring process might more efficiently extract ECG and
EGCG, which obtains galloyl moiety (Table 1). Liquid chromatography–tandem mass spectrometry
(LC-MS/MS) analysis of Strong Powder tea and Strong Leaf tea showed negativemolecular ion
[M
´
H]
´
with m/z 289.07, 305.07, 441.08, and 457.08, indicating catechin/EC, gallocatechin/EGC,
catechin gallate/ECG, and gallocatechin gallate/EGCG, respectively (Figure 3 and Table 2). These data
suggest that Strong Powder tea contains significantly higher amounts of EGC, ECG, and EGCG, and a
lower amount of EC compared to Strong Leaf tea (p < 0.05).
Molecules 2016, 21, 474 5 of 12
Molecules 2016, 21, 474 5 of 12
Figure 3. Differences of catechins between Powder and Leaf green tea in liquid chromatography–
mass spectrometry (LC-MS) chromatogram (negative mode, representative data in three
measurements): base peak chromatogram (a); and extracted ion chromatogram of indicated catechins
((b)–(e)).
Table 2. Differences of catechin area between the Strong Powder tea and Strong Leaf tea measured
by liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis.
Search Compound
Retention Time
(min)
[M H]
Area
Strong Powder Strong Leaf
Catechin/EC 3.9 289.07 2,684,378 ± 89,484.5 3,241,299 ± 192,287.7 *
Gallocatechin/EGC 3.5 305.07 6,418,883 ± 149,286.8 * 6,041,930 ± 16,410.1
Catechin gallate/ECG 4.3 441.08 1,364,591 ± 16,486.5 * 358,874 ± 19,209.7
Gallocatechin gallate/
EGCG
3.9 457.08 3,590,762 ± 128,970.1 * 1,043,276 ± 67,495.9
Retention time was calculated by the average of six measurements. Strong Powder and Strong Leaf
indicate powdered tea and leaf tea (powder/leaf contents: 0.96 g/80 mL green tea), respectively. All
area values represent the mean ± SD of three measurements. * indicates significant difference
between Strong Powder and Strong Leaf (Welch’s t test, p < 0.05).
2.3. Effect of Powdered Tea and Leaf Tea on ROS
To appraise whether the physical and chemical differences observed in leaves and powdered
tealeaves might have been coupled with functional differences, we examined the inhibitory effect on
Figure 3.
Differences of catechins between Powder and Leaf green tea in liquid chromatography–mass
spectrometry (LC-MS) chromatogram (negative mode, representative data in three measurements):
base peak chromatogram (a); and extracted ion chromatogram of indicated catechins ((b)–(e)).
Table 2.
Differences of catechin area between the Strong Powder tea and Strong Leaf tea measured by
liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis.
Search Compound
Retention Time (min)
[M ´ H]
´
Area
Strong Powder Strong Leaf
Catechin/EC 3.9 289.07 2,684,378 ˘ 89,484.5 3,241,299 ˘ 192,287.7 *
Gallocatechin/EGC 3.5 305.07 6,418,883 ˘ 149,286.8 * 6,041,930 ˘ 16,410.1
Catechin gallate/ECG 4.3 441.08 1,364,591 ˘ 16,486.5 * 358,874 ˘ 19,209.7
Gallocatechin gallate/
EGCG
3.9 457.08 3,590,762 ˘ 128,970.1 * 1,043,276 ˘ 67,495.9
Retention time was calculated by the average of six measurements. Strong Powder and Strong Leaf indicate
powdered tea and leaf tea (powder/leaf contents: 0.96 g/80 mL green tea), respectively. All area values represent
the mean
˘
SD of three measurements. * indicates significant difference between Strong Powder and Strong
Leaf (Welch’s t test, p < 0.05).
2.3. Effect of Powdered Tea and Leaf Tea on ROS
To appraise whether the physical and chemical differences observed in leaves and powdered
tealeaves might have been coupled with functional differences, we examined the inhibitory effect on
ROS
in vitro
(Figure 4). When the same amount of powder and leaves were compared, the superoxide
dismutase (SOD)-like activity, which counteracts the ROS effect, showed higher tendency in the
Powder tea and Strong Powder tea than in the leaf teas (Figure 4a). Consistently, ROS inhibition effect
in the Jurkat human leukemia cell line was higher for both powder teas compared to the same amount
of leaf teas (Figure 4b).
Molecules 2016, 21, 474 6 of 12
Molecules 2016, 21, 474 6 of 12
ROS in vitro (Figure 4). When the same amount of powder and leaves were compared, the
superoxide dismutase (SOD)-like activity, which counteracts the ROS effect, showed higher
tendency in the Powder tea and Strong Powder tea than in the leaf teas (Figure 4a). Consistently,
ROS inhibition effect in the Jurkat human leukemia cell line was higher for both powder teas
compared to the same amount of leaf teas (Figure 4b).
Figure 4. Differences in
reactive oxygen species (
ROS) inhibitory effects of green teas in vitro: (a)
super
oxide dismutase (
SOD)-like activity of green teas at indicated dilution rate; and (b)
intracellular ROS intensity in Jurkat cell line added with green teas (1/500 dilution). * and # indicate
differences between Powder vs. Leaf tea and Strong Powder vs. Strong Leaf tea at 5% significant
level, respectively (Bonferroni/Dunn method).
3. Discussion
This study aimed to investigate the differences in composition and function between leaf tea
and powdered tea. We revealed the physical and chemical component changes after the powdering
process, which may be the basis of different activity in vitro.
3.1. Physical Properties of the Powdered Green Tea
Comparison of the powdering process revealed that the ceramic mill produced the smallest tea
particles. A previous report from Sawamura et al. [20] indicated that a set of millstones had higher
shearing force and produced lower roundness of particles than a jet mill. In line with Sawamura’s
study, our results, using Scanning Electron Microscope (SEM) images of green tea powder derived
by a ceramic mill, confirm the predominant presence of torn structures rather than other methods
(Figure 1). Additionally, the ceramic mill and the millstone method produced particles of similar
sizes in the report (15.01 µm vs. 15–20 µm [20,21]). Therefore, tea powder with the ceramic mill may
show a similar property of tea powder produced with the millstones in the historical grinding
method.
3.2. Catechin and Caffeine Contents of the Powdered Green Tea
The powdering process increased the catechin contents, especially EGCG, in the green tea.
There are few reports comparing the amount of catechin in the tea liquid before and after the
powdering process, since general studies compare leaf teas and powdered teas from different
Figure 4.
Differences in reactive oxygen species (ROS) inhibitory effects of green teas
in vitro
:
(
a
) superoxide dismutase (SOD)-like activity of green teas at indicated dilution rate; and (
b
) intracellular
ROS intensity in Jurkat cell line added with green teas (1/500 dilution). * and # indicate differences
between Powder vs. Leaf tea and Strong Powder vs. Strong Leaf tea at 5% significant level, respectively
(Bonferroni/Dunn method).
3. Discussion
This study aimed to investigate the differences in composition and function between leaf tea and
powdered tea. We revealed the physical and chemical component changes after the powdering process,
which may be the basis of different activity in vitro.
3.1. Physical Properties of the Powdered Green Tea
Comparison of the powdering process revealed that the ceramic mill produced the smallest tea
particles. A previous report from Sawamura et al. [
20
] indicated that a set of millstones had higher
shearing force and produced lower roundness of particles than a jet mill. In line with Sawamura’s
study, our results, using Scanning Electron Microscope (SEM) images of green tea powder derived
by a ceramic mill, confirm the predominant presence of torn structures rather than other methods
(Figure 1). Additionally, the ceramic mill and the millstone method produced particles of similar sizes
in the report (15.01
µ
m vs. 15–20
µ
m [
20
,
21
]). Therefore, tea powder with the ceramic mill may show a
similar property of tea powder produced with the millstones in the historical grinding method.
3.2. Catechin and Caffeine Contents of the Powdered Green Tea
The powdering process increased the catechin contents, especially EGCG, in the green tea.
There are few reports comparing the amount of catechin in the tea liquid before and after the powdering
process, since general studies compare leaf teas and powdered teas from different brands. In a previous
study [
22
], leaves powdering increased the intake of catechins from green tea (Benifuuki) in rats in
comparison with leaf infusion. In line with this study, our data suggest that the increase of the catechin
extraction due to powdering process (Table 1) may enhance its corresponding intake in rats.
Shishikura et al. [
23
] showed that EGCG and caffeine were highly contained in powdered
tea (EGCG: 183.2
˘
19.8 mg and caffeine 138.1
˘
17.7 mg on average in 600-mL Uji-matt-cha and
Gyokuro-cha) after 1-min brewing. On the other hand, leaf tea contained 154.6
˘
17.2 mg EGCG and
121.4
˘
4.6 mg caffeine in 600-mL Sayama-cha [
23
]. Compared to other reports, which used organic
Molecules 2016, 21, 474 7 of 12
solvents or longer brewing time for catechin extraction from tealeaves, Shishikura’s report addressed
brewing styles relevant to dietary consumption such as the use of boiling water for brewing and shorter
brewing times (1 and 5 min). We used hot water for brewing, a 1-min brewing time, and a stirrer,
because these conditions were similar to those in a tea ceremony. According to our data (Table 1),
an estimated 600-mL of Powder teas contained 126.4–369.1 mg EGCG and 72.9–187.1 mg caffeine,
while an estimated 600-mL of Leaf teas contained 34.7–120.1 mg EGCG and 46.7–146.4 mg caffeine.
LC-MS/MS data also indicated the higher contents of EGCG (Figure 3 and Table 2). These data suggest
that the powdering process promoted the extraction of EGCG and caffeine.
In several clinical studies, the effects of green tea or green tea extract on weight management
were investigated. Thielecke et al. [
6
] reviewed the clinical studies focused on a catechin intake of
140.8–1206.9 mg/day, EGCG intake of 100–595.8 mg/day, and caffeine intake of 27–236.7 mg/day.
Among 12 such studies, nine studies showed a tendency for weight, fat mass, or Body Mass Index (BMI)
to decrease, while two studies showed no change or a tendency for these factors to increase, and one
study demonstrated the result of caffeine consumption dependency. Recent studies suggested that the
consumption of both caffeine and catechin affected body weight management [
24
,
25
]. Moreover, EGCG
are known to reduce cholesterol solubility in bile acid micelles, which are related to fat absorption,
due to interaction of bile salt [
26
] and phosphatidylcholine [
27
]. Thus, powdered green teas may
have potential weight management benefits owing to higher extraction efficacy of catechin, especially
EGCG, and caffeine contents, although we should pay attention to acceptable daily intake.
As for the intake of polyphenols, most dietary polyphenols are known to be metabolized in
phase II reaction (O-methylated, sulfated, glucuronide conjugates, etc.) or metabolized/degraded
by microbiota [
28
,
29
]. Stalmach et al. [
30
] investigated the absorption, metabolism, and excretion
of Choladi green tea flavan-3-ols in human using LC-MS system. They detected the 15 metabolites
of the flavan-3-ols in urine and the 10 metabolites and intact forms of EGCG and ECG in plasma.
Since galloyl moiety of EGCG and ECG was thought to interfere with the metabolism, intact forms
of EGCG and ECG were detected in plasma [
28
]. After ingestion of the 500-mL Choladi green tea
containing 230
˘
6
µ
mol EGCG and 49
˘
1
µ
mol ECG, the C
max
(maximum concentration) in plasma
of EGCG and ECG were 55
˘
12 nM and 25
˘
3.0 nM, respectively [
30
]. In our study, Powder green
teas contained higher concentration of EGCG and ECG, which obtain galloyl moiety, than Leaf teas at
the same powder/leaf contents (Table 1). Since an estimated 500-mL of Powdered green teas contained
230–671
µ
mol EGCG and 40–111
µ
mol ECG (calculated from Table 1), ingestion of Strong Powder tea
may contribute to the higher C
max
or AUC (area under the concentration-time curve) of EGCG and
ECG than that of Choladi green tea, while Powder tea may contribute to the similar results of Choladi
green tea due to similar concentration of EGCG and ECG. Moreover, particles in the powdered teas
may be affected by the digestion in the gastrointestinal tract. Therefore, investigation of bioavailability
of powered teas will contribute to revealing the novel function of green tea.
3.3. Effect on ROS Activity
Both Powder teas showed the tendency of higher inhibitory effect on ROS than the same amount
of Leaf teas. Catechins (EC, ECG, EGC, and EGCG) are known to be antioxidant compounds. Among
the catechins, the anti-oxidant activity was higher for EGCG than for EGC, ECG, and EC [
13
,
17
,
31
,
32
].
Since the powdering process increased the EGCG extraction by more than three times compared with
that in Leaf teas (Table 1), higher anti-oxidant activity was expected. Accordingly, both Powder teas
showed the tendency of higher SOD-like activity and inhibition of intracellular ROS compared to the
same amount of Leaf teas (Figure 4a,b).
On the other hand, Strong Leaf tea has a higher inhibition activity of intracellular ROS than
Powder tea, although both teas contained a similar amount of EGCG (200.1 vs. 210.6
µ
g/mL) and
ECG (33.3 vs. 35.7
µ
g/mL) and showed similar SOD-like activity (Figure 4a,b, and Table 1). Therefore,
the difference of shapes (leaf and powder) or other catechin contents may have an effect on intracellular
ROS. Further study is needed to reveal the ROS inhibitory mechanism of powdered tea.
Molecules 2016, 21, 474 8 of 12
4. Materials and Methods
4.1. Tea Preparation and Powdering Process
Green tea leaves (second picked tea leaves) were purchased from a tea specialty shop in Tokyo,
Japan. For powdering process of green tea leaves, we used a set of ceramic mills (Figure 5) in a tea
maker, Healsio Ocha Presso (TE-GS10A, Sharp, Osaka, Japan), a ball mill with an alumina ball, and a
mixer with stainless cutter for cooking use for 3–4 min (mill-contact time of tea leaf was approximately
30 s), 420 min, and 5 min, respectively.
Molecules 2016, 21, 474 8 of 12
than three times compared with that in Leaf teas (Table 1), higher anti-oxidant activity was expected.
Accordingly, both Powder teas showed the tendency of higher SOD-like activity and inhibition of
intracellular ROS compared to the same amount of Leaf teas (Figure 4a,b).
On the other hand, Strong Leaf tea has a higher inhibition activity of intracellular ROS than
Powder tea, although both teas contained a similar amount of EGCG (200.1 vs. 210.6 µg/mL) and
ECG (33.3 vs. 35.7 µg/mL) and showed similar SOD-like activity (Figure 4a,b, and Table 1).
Therefore, the difference of shapes (leaf and powder) or other catechin contents may have an effect
on intracellular ROS. Further study is needed to reveal the ROS inhibitory mechanism of powdered
tea.
4. Materials and Methods
4.1. Tea Preparation and Powdering Process
Green tea leaves (second picked tea leaves) were purchased from a tea specialty shop in Tokyo,
Japan. For powdering process of green tea leaves, we used a set of ceramic mills (Figure 5) in a tea
maker, Healsio Ocha Presso (TE-GS10A, Sharp, Osaka, Japan), a ball mill with an alumina ball, and a
mixer with stainless cutter for cooking use for 3–4 min (mill-contact time of tea leaf was
approximately 30 s), 420 min, and 5 min, respectively.
Figure 5. A set of ceramic mill set in a tea maker.
Because Shishikura et al. [23] mentioned that most individuals in their laboratory (n = 34) spend
less than 1 min preparing a cup of tea in their paper, we adopted a 1-min brewing time for green tea
preparation. Then hot tap water after boiling (60 °C, 80 mL) was added to the tea powder or leaf
(0.36 g or 0.96 g) in a conical flask and stirred for 1 min with a magnetic stirrer (SW-RS077, Nisshin
Rika, Tokyo, Japan). As for regular tea, hot tap water after boiling (60 °C, 80 mL) was added to
tealeaf (2.0 g) in a conical flask and placed for 1 min (no stirring). The aim of regular-tea
investigation was the comparison with the general green tea, which we drink daily. After being
placed for 1-min on ice, all the tea solutions were transferred into a light-shielding glass bottle using
a 10-mL pipet and refrigerated at 20 °C until examination. For investigating the particle distribution
(Section 4.4.), the regular tea was filtered with a tea strainer after brewing instead of 10-mL pipet
transfer.
4.2. Chemicals
()-Epigallocatechin (98%), ()-Epicattechin (98%), Caffeine anhydrous (98.5%), Phosphoric
Acid, Ortho (85%), Acetonitrile (99.8%, used for HPLC analysis in this paper) were purchased from
Nacalai tesque, Kyoto, Japan. (+)-Catechin Hydrate (>95.0%), ()-Epicatechin Gallate (>98.0%),
()-Epigallocatechin Gallate Hydrate (>98%), tert-butyl hydroperoxide (70% in Water) were
purchased from Tokyo Chemical Industry, Tokyo, Japan. Acetonitrile for High Performance Liquid
Chromatography (99.8+%, used for LC-MS/MS analysis in this paper) and Sodium Carbonate
(99.8+%) were purchased from Wako Pure Chemical Industries, Tokyo, Japan. Folin–Denis’ reagent
and 2’,7’-dichlorofluorescein diacetate (97%, DCFDA) was purchased from Merck KGaA
(Sigma-Aldrich), Darmstadt, Germany. Anmonium formate solution, and Formic acid-Acetonitrile
were purchased from Kanto Kagaku, Tokyo, Japan. Sodium hexametaphosphate was purchased
Figure 5. A set of ceramic mill set in a tea maker.
Because Shishikura et al. [
23
] mentioned that most individuals in their laboratory (n = 34) spend
less than 1 min preparing a cup of tea in their paper, we adopted a 1-min brewing time for green tea
preparation. Then hot tap water after boiling (60
˝
C, 80 mL) was added to the tea powder or leaf
(0.36 g or 0.96 g) in a conical flask and stirred for 1 min with a magnetic stirrer (SW-RS077, Nisshin
Rika, Tokyo, Japan). As for regular tea, hot tap water after boiling (60
˝
C, 80 mL) was added to tealeaf
(2.0 g) in a conical flask and placed for 1 min (no stirring). The aim of regular-tea investigation was
the comparison with the general green tea, which we drink daily. After being placed for 1-min on
ice, all the tea solutions were transferred into a light-shielding glass bottle using a 10-mL pipet and
refrigerated at
´
20
˝
C until examination. For investigating the particle distribution (Section 4.4.),
the regular tea was filtered with a tea strainer after brewing instead of 10-mL pipet transfer.
4.2. Chemicals
(
´
)-Epigallocatechin (98%), (
´
)-Epicattechin (98%), Caffeine anhydrous (98.5%), Phosphoric
Acid, Ortho (85%), Acetonitrile (99.8%, used for HPLC analysis in this paper) were purchased
from Nacalai tesque, Kyoto, Japan. (+)-Catechin Hydrate (>95.0%), (
´
)-Epicatechin Gallate
(>98.0%), (
´
)-Epigallocatechin Gallate Hydrate (>98%), tert-butyl hydroperoxide (70% in Water)
were purchased from Tokyo Chemical Industry, Tokyo, Japan. Acetonitrile for High Performance
Liquid Chromatography (99.8+%, used for LC-MS/MS analysis in this paper) and Sodium Carbonate
(99.8+%) were purchased from Wako Pure Chemical Industries, Tokyo, Japan. Folin–Denis’ reagent and
2’,7’-dichlorofluorescein diacetate (
ě
97%, DCFDA) was purchased from Merck KGaA (Sigma-Aldrich),
Darmstadt, Germany. Anmonium formate solution, and Formic acid-Acetonitrile were purchased
from Kanto Kagaku, Tokyo, Japan. Sodium hexametaphosphate was purchased from Mitejima
Chemical, Osaka, Japan. SOD Assay Kit-WST was purchased from Dojindo Molecular Technologies,
Kumamoto, Japan.
4.3. Observation of Tea Powders and Leaves with a SEM and a Multifocal Optical Microscope
For the observation with an electron microscope, tea powders and leaves were scattered on
a carbon tape, followed by blowing the excess powders or leaves. Then powders and leaves
were observed with SEM (JSM-5800LV, JEOL, Tokyo, Japan) using accelerating voltage of 15 kV
at magnification of 250 and 1000 times. For the multifocal optical observation, 10
µ
L of tea was injected
into a plastic slide and then images were recorded with an automated cell counter (TC20, Biorad,
Molecules 2016, 21, 474 9 of 12
CA, USA). The optical images were analyzed with an image analysis software (WinRoof 2013,
Mitani Corporation, Tokyo, Japan) for counting the particles in the picture (around 4 mm
2
).
4.4. Size Distribution in Tea Liquid
The size distribution of tea powders was measured with laser diffraction particle size analyzer
(SALD 1100, Shimadzu Corporation, Kyoto, Japan) after dispersion in 1% sodium hexametaphosphate
in water. For the measurement of particles size in the regular tea, tea liquid after filtration with a tea
strainer (Section 4.1.) was used for exclusion of large tealeaves.
4.5. Catechin and Caffeine Analysis with HPLC System
For quantification of major catechins and caffeine, EC, ECG, EGC, EGCG and caffeine were
analyzed in the method refer to the paper of Terada et al. [
33
] and partially modified. The peak of
catechins and caffeine was detected at 280 nm absorbance with a HPLC system (LC-10A, Shimadzu
corporation, Kyoto, Japan) equipped with CAPCELL Pack C18 (UG120S-5, 4.6
ˆ
150 mm, Shiseido).
Column oven temperature was at 43
˝
C. In reference to the previous paper, the tea samples were
mixed with triple volume of acetonitrile then filtered with PVDF membrane (Acrodisc LC PVDF,
0.45
µ
m, 13 mm) quickly. Gradient separation was carried with eluent A (0.1% acetonitrile and
5% N,N-dimethylformamide in 0.1% phosphoric acid water solution) and eluent B (acetonitrile).
The volume of the injected sample was 10
µ
L and flow rate was 1.0 mL/min. The gradient program
was as follows: Rate of elute B: 0–30 min: 1%
Ñ
15%; 30–40 min: 15%
Ñ
90%; and 40–40.1 min: 90%
Ñ
1%.
As the standard, (
´
)-epigallocatechin, epicatechin, (
´
)-epicatechin gallate (
´
)-Epigallocatechin Gallate
Hydrate, and Caffeine anhydrous were used in the range of 0–500 µg/mL.
4.6. Total Polyphenol Concentration
The total phenol of teas was quantified with the Folin–Denis’ reagent assay [
34
] (refer to our
previous paper [
35
]). Each sample was diluted with purified water (1/5 dilution) and added to the
Folin–Denis’ reagent and 10% sodium carbonate solution (Diluted sample: Folin–Denis’ reagent: 10%
sodium carbonate solution = 1:1:1). After the solution was placed for 20 min at room temperature,
the solution was centrifuged at 10,000 g and room temperature for 1 min. Then, 700 nm absorbance was
measured with a multimode plate reader (EnSpire, PerkinElmer, Waltham, MA, USA). (+)-Catechin
Hydrate was used as standard in the range 0–1000
µ
g/mL. The phenol contents of the teas were
calculated as catechin equivalents (mg CE/mL).
4.7. Chemical Components Analysis with LC-MS/MS System
The chemical components of strong powder tea and strong leaf tea were analyzed with LC-MS/MS
system (Maxis 3G, Bruker, MA, USA) equipped with ACQUITY UPLC BEH C8 Column (1.7
µ
m,
2.1 mm
ˆ
50 mm, Waters, MA, USA). Column oven temperature was 40
˝
C. Mass spectra were
acquired in ESI negative modes. The tea samples were filtrated with the Acrodisc PVDF membrane
filter. The binary gradient 10 mM ammonium formate in water (eluent A) and acetonitrile containing
10 mM ammonium formate (eluent B) in the negative mode was applied with injection volume of 5
µ
L
at a constant flowrate of 0.2 mL/min. The gradient program was as follows: Rate of elute A: 0–10 min:
0%
Ñ
95%; 10–13 min: 95%; and 13–13.1 min: 95%
Ñ
0%. The detected molecular masses were found in
the Human Metabolome Database [36] using MS Search.
4.8. Measurement of SOD-Like Activity
In reference to our previous paper [
35
] and manufacturers’ protocol, the tea samples
(no pretreatment) were diluted in the range of 1–32,000 dilution and analyzed with SOD Assay
Kit-WST (Inhibition assay of xanthine oxidase). Inhibition rate (%) was calculated by the ratio of the
control (water).
Molecules 2016, 21, 474 10 of 12
4.9. Inhibition of Intracellular ROS in a T Cell Line
Jurkat human leukemic T cell line was used for the measurement of intracellular ROS. Referring
to the method by Bass et al. [
37
] and partially modified, 20
µ
M 2’,7’-dichlorofluorescein diacetate was
added to 1.25
ˆ
10
5
cells/mL of the cells, then incubated at 37
˝
C for 30 min (5% CO
2
). Next, the tea
samples were added to the cells at the 500 times dilution followed by 30-min incubation. After the
incubation, 200
µ
M tert-butyl hydroperoxide was added and incubated for 1 h. Then the fluorescent of
intracellular ROS was measured with the Enspire plate reader (Ex 485 nm/Em 535nm). Inhibition rate
(%) was calculated by the ratio of control (water).
4.10. Data Analysis
All statistical analyses were carried out in triplicate. The mean
˘
standard deviation (SD)
(three measurements) was presented. Statistical significance was calculated in Bonferroni–Dunn
multiple comparison test or Welch’s t test with the Microsoft Office Excel 2013 (Microsoft, Redmond,
WA, USA) and the add-in software Statcel 3 (OMS publishing Inc., Saitama, Japan). Significance level
was set at 5%.
5. Conclusions
In conclusion, the powdering process of green tealeaves with the ceramic mill increased the
extracted catechin concentration, especially that of EGCG. Moreover, these powdered teas showed
a tendency of higher inhibitory effect of the ROS
in vitro
. Since powdered tea may have different
function from leaf tea, further study will be needed.
Acknowledgments:
We thank Yasuko Tomizawa (Tokyo Women’s Medical University) for useful advice about
this project. This study was partially supported by grants and endowments from Sharp Corporation and partially
supported (technically advised) by NIMS Molecule & Material Synthesis Platform in “Nanotechnology Platform
Project” operated by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. We thank
Editage and MDPI English Editing Department for English editing.
Author Contributions:
K.F., Y.K., and Y.M. conceived and designed the experiments; K.F., T.I.,
H.S. (Hidekazu Shima), K.T., H.S. (Hideki Saito), and M.O. performed the experiments; K.F., T.I., K.T. analyzed
the data; A.Y. contributed to coordinate the ceramic mill system; and K.F. wrote the paper.
Conflicts of Interest:
This research was funded by Sharp Corporation. K.F. received the grants and endowments
for this study from Sharp Corporation. H.S. (Hidekazu Shima), M.O., A.Y., and Y.K. are employees of Sharp
Corporation. Tea brewing system (Ocha Presso) using the ceramic mills reported in this manuscript was developed
by Sharp Corporation. Some technologies related to the tea brewing system are pending patents applied by Sharp
Corporation. The Ocha Presso brewing system (including the ceramic mills) is commercially available.
Abbreviations
The following abbreviations are used in this manuscript:
AUC Area under the concentration-time curve
BMI Body Mass Index
C
max
Maximum concentration
EC Epicatechin
ECG Epicatechin Gallate
EGC Epigallocatechin
EGCG Epigallocatechin Gallate
HPLC High-performance Liquid Chromatography
LC-MS Liquid Chromatography–Mass Spectrometry
LC-MS/MS Liquid Chromatography–tandem Mass Spectrometry
ROS Reactive Oxygen Species
SEM Scanning Electron Microscope
SD Standard Deviation
SOD Superoxide Dismutase
Molecules 2016, 21, 474 11 of 12
References
1.
Ui, A.; Kuriyama, S.; Kakizaki, M.; Sone, T.; Nakaya, N.; Ohmori-Matsuda, K.; Hozawa, A.; Nishino, Y.; Tsuji, I.
Green tea consumption and the risk of liver cancer in Japan: The Ohsaki Cohort study. Cancer Causes Control
2009, 20, 1939–1945. [CrossRef] [PubMed]
2.
Inoue, M.; Sasazuki, S.; Wakai, K.; Suzuki, T.; Matsuo, K.; Shimazu, T.; Tsuji, I.; Tanaka, K.; Mizoue, T.;
Nagata, C.; et al. Green tea consumption and gastric cancer in Japanese: A pooled analysis of six cohort
studies. Gut 2009, 58, 1323–1332. [CrossRef] [PubMed]
3.
Maeda-Yamamoto, M.; Ema, K.; Shibuichi, I.
In vitro
and
in vivo
anti-allergic effects of ‘benifuuki’ green
tea containing O-methylated catechin and ginger extract enhancement. Cytotechnology
2007
, 55, 135–142.
[CrossRef] [PubMed]
4.
Ide, K.; Yamada, H.; Takuma, N.; Park, M.; Wakamiya, N.; Nakase, J.; Ukawa, Y.; Sagesaka, Y.M. Green
tea consumption affects cognitive dysfunction in the elderly: A pilot study. Nutrients
2014
, 6, 4032–4042.
[CrossRef] [PubMed]
5.
Fukino, Y.; Ikeda, A.; Maruyama, K.; Aoki, N.; Okubo, T.; Iso, H. Randomized controlled trial for an effect
of green tea-extract powder supplementation on glucose abnormalities. Eur J. Clin Nutr.
2008
, 62, 953–960.
[CrossRef] [PubMed]
6.
Thielecke, F.; Boschmann, M. The potential role of green tea catechins in the prevention of the metabolic
syndrome—A review. Phytochemistry 2009, 70, 11–24. [CrossRef] [PubMed]
7.
Kokubo, Y.; Iso, H.; Saito, I.; Yamagishi, K.; Yatsuya, H.; Ishihara, J.; Inoue, M.; Tsugane, S. The impact of
green tea and coffee consumption on the reduced risk of stroke incidence in Japanese population: The Japan
public health center-based study cohort. Stroke 2013, 44, 1369–1374. [CrossRef] [PubMed]
8.
Saito, E.; Inoue, M.; Sawada, N.; Shimazu, T.; Yamaji, T.; Iwasaki, M.; Sasazuki, S.; Noda, M.; Iso, H.;
Tsugane, S.; et al. Association of green tea consumption with mortality due to all causes and major causes
of death in a Japanese population: The Japan Public Health Center-based Prospective Study (JPHC Study).
Ann. Epidemiol. 2015, 25, 512–518. [CrossRef] [PubMed]
9.
Sawamura, S. Particle Size and Taste of Matcha Produced before the Middle Ages. J. Cook. Sci. Japan
2011
,
44, 231–237.
10.
Yamada, T. Kissa no Rekishi. In Cha Daihyakka; Kyokai, N.-G.B., Ed.; Nousan Gyoson Bunka Kyokai: Tokyo,
Japan, 2008; Volume 1, pp. 67–81.
11.
Zhang, J. Seicha no Shurui, Gijutsu, Seichasha. In Sado to chanoyu: Nihoncha bunka shiron; Tankosha: Kyoto,
Japan, 2004; pp. 153–200.
12.
Ikegaya, K.; Takayanagi, H.; Anan, T. Chemical Composition of Mat-cha. Tea Res. J.
1984
, 60, 79–81. [CrossRef]
13.
Matsuzaki, T.; Hara, Y. Antioxidative activity of tea leaf catechins. Nippon Nogeikagaku Kaishi
1985
, 59, 129–134.
[CrossRef]
14.
Shimada, K. Determination of Tea-Leaf Saponins and Water-Soluble Pectin in a Green Tea Infusion.
J. Home Econ. Japan 2003, 54, 957–962.
15.
Saijo, R.; Takeda, Y. HPLC Analysis of Catechins in Various Kinds of Green Teas Produced in Japan and
Abroad. Nippon Shokuhin Kagaku Kogaku Kaishi 1999, 46, 138–147. [CrossRef]
16.
Goto, T.; Nagashima, H.; Yoshida, Y.; Kiso, M. Contents of Individual Tea Catechins and Caffeine in Japanese
Green Tea. Tea Res. J. 1996, 83, 21–28. [CrossRef]
17.
Nanjo, F.; Mori, M.; Goto, K.; Hara, Y. Radical scavenging activity of tea catechins and their related
compounds. Biosci. Biotechnol. Biochem. 1999, 63, 1621–1623. [CrossRef] [PubMed]
18.
Legeay, S.; Rodier, M.; Fillon, L.; Faure, S.; Clere, N. Epigallocatechin Gallate: A Review of Its Beneficial
Properties to Prevent Metabolic Syndrome. Nutrients 2015, 7, 5443–5468. [CrossRef] [PubMed]
19.
Onishi, I.; Morimoto, T.; Togashi, Y. Grinding Method of Tencha and Physical Properties of Powdered Green
Tea (Ceremony Tea). Tea Res. J. 1973, 39, 23–28. [CrossRef]
20.
Sawamura, S.; Haraguchi, Y.; Ikeda, H.; Sonoda, J. Properties and Shapes of Matcha with Various Milling
Method. Nippon Shokuhin Kagaku Kogaku Kaishi. 2010, 57, 304–309. [CrossRef]
21.
Haraguchi, Y.; Imada, Y.; Sawamura, S. Production and Characterization of Fine Matcha for Processed Food.
Nippon Shokuhin Kagaku Kogaku Kaishi. 2003, 50, 468–473. [CrossRef]
Molecules 2016, 21, 474 12 of 12
22.
Maeda-Yamamoto, M.; Ema, K.; Tokuda, Y.; Monobe, M.; Tachibana, H.; Sameshima, Y.; Kuriyama, S. Effect
of green tea powder (Camellia sinensis L. cv. Benifuuki) particle size on O-methylated EGCG absorption in
rats; The Kakegawa Study. Cytotechnology 2011, 63, 171–179. [CrossRef] [PubMed]
23.
Shishikura, Y.; Khokhar, S. Factors affecting the levels of catechins and caffeine in tea beverage: Estimated
daily intakes and antioxidant activity. J. Sci. Food Agric. 2005, 85, 2125–2133. [CrossRef]
24.
Westerterp-Plantenga, M.S.; Lejeune, M.P.; Kovacs, E.M. Body weight loss and weight maintenance in
relation to habitual caffeine intake and green tea supplementation. Obes. Res.
2005
, 13, 1195–1204. [CrossRef]
[PubMed]
25.
Hursel, R.; Westerterp-Plantenga, M.S. Catechin- and caffeine-rich teas for control of body weight in humans.
Am. J. Clin. Nutr. 2013, 98, 1682S–1693S. [CrossRef] [PubMed]
26.
Ogawa, K.; Hirose, S.; Nagaoka, S.; Yanase, E. Interaction between Tea Polyphenols and Bile Acid Inhibits
Micellar Cholesterol Solubility. J. Agric. Food Chem. 2016, 64, 204–209. [CrossRef] [PubMed]
27.
Kobayashi, M.; Nishizawa, M.; Inoue, N.; Hosoya, T.; Yoshida, M.; Ukawa, Y.; Sagesaka, Y.M.; Doi, T.;
Nakayama, T.; Kumazawa, S.; et al. Epigallocatechin gallate decreases the micellar solubility of cholesterol
via specific interaction with phosphatidylcholine. J. Agric. Food Chem.
2014
, 62, 2881–2890. [CrossRef]
[PubMed]
28.
Del Rio, D.; Rodriguez-Mateos, A.; Spencer, J.P.; Tognolini, M.; Borges, G.; Crozier, A. Dietary (poly)phenolics
in human health: Structures, bioavailability, and evidence of protective effects against chronic diseases.
Antioxid. Redox Signal. 2013, 18, 1818–1892. [CrossRef] [PubMed]
29.
Rodriguez-Mateos, A.; Vauzour, D.; Krueger, C.G.; Shanmuganayagam, D.; Reed, J.; Calani, L.; Mena, P.;
Del Rio, D.; Crozier, A. Bioavailability, bioactivity and impact on health of dietary flavonoids and related
compounds: An update. Arch. Toxicol. 2014, 88, 1803–1853. [CrossRef] [PubMed]
30.
Stalmach, A.; Troufflard, S.; Serafini, M.; Crozier, A. Absorption, metabolism and excretion of Choladi green
tea flavan-3-ols by humans. Mol. Nutr. Food Res. 2009, 53 Supplement, S44–S53. [CrossRef] [PubMed]
31.
Yoshino, K.; Hara, Y.; Sano, M.; Tomita, I. Antioxidative effects of black tea theaflavins and thearubigin on
lipid peroxidation of rat liver homogenates induced by tert-butyl hydroperoxide. Biol. Pharm. Bull.
1994
,
17, 146–149. [CrossRef] [PubMed]
32.
Hashimoto, F.; Ono, M.; Masuoka, C.; Ito, Y.; Sakata, Y.; Shimizu, K.; Nonaka, G.; Nishioka, I.; Nohara, T.
Evaluation of the anti-oxidative effect (
in vitro
) of tea polyphenols. Biosci. Biotechnol. Biochem.
2003
,
67, 396–401. [CrossRef] [PubMed]
33.
Terada, S.; Maeda, Y.; Masui, T.; Suzuki, Y.; Ina, K. Comparison of caffeine and catechin components in
infusion of various tea (green, oolong and black tea) and tea drinks. Nippon Shokuhin Kagaku Kogaku Kaishi.
1987, 34, 20–27. [CrossRef]
34.
Singleton, V.L.; Rossi, J.A. Colorimetry of Total Phenolics with Phosphomolybdic-Phosphotungstic Acid
Reagents. Am. J. Enol. Vitic. 1965, 16, 144–158.
35.
Kamitani, I.; Fujioka, K.; Kamada, M.; Ikeda, K.; Manome, Y. Functional Investigation of Sweet Red Bean
Pastes as Anti-oxidant Food: Polyphenol Contents, Superoxide Dismutase Activity, and Inhibitory Effects on
Reactive Oxygen Species. Nippon Shokuhin Kagaku Kogaku Kaishi. 2015, 62, 349–353. [CrossRef]
36. Human Metabolome Database. Available online: http://www.hmdb.ca/ (accessed on 1 February 2016).
37.
Bass, D.A.; Parce, J.W.; Dechatelet, L.R.; Szejda, P.; Seeds, M.C.; Thomas, M. Flow cytometric studies of
oxidative product formation by neutrophils: A graded response to membrane stimulation. J. Immunol.
1983
,
130, 1910–1917. [PubMed]
Sample Availability: Not available.
©
2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
(CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
... For preparing matcha tea, the tea plants are grown under shade (about 90% shade) by covering the cultivation areas/fields with different materials (Fig. 1). Thus cultivated tea leaves are picked, washed, dried and then ground using stone mills to make powder known as matcha tea powder (Fujioka et al., 2016) (Fig. 1). The use of stone mills to make tea leaves powder is reported to have started in the 11th century in China and later started in Japan in the 14th century, which supports the long history of use of tea powders (Fujioka et al., 2016). ...
... Thus cultivated tea leaves are picked, washed, dried and then ground using stone mills to make powder known as matcha tea powder (Fujioka et al., 2016) (Fig. 1). The use of stone mills to make tea leaves powder is reported to have started in the 11th century in China and later started in Japan in the 14th century, which supports the long history of use of tea powders (Fujioka et al., 2016). For consuming matcha powder, the whole powder is mixed with hot water so that the whole content of leaves are consumed not only the extract Weiss & Anderton, 2003). ...
... Traditionally, stone mills are used to prepare matcha powder from tea leaves. Recently, Fujioka et al. (2016) reported that the use of ceramic mills to make powders can enhance the catechin extraction from the powder and also the extract obtained from such powder had stronger antioxidant activity. ...
Article
Background The interest in the plant-derived healthy foods, nutraceuticals, functional foods and food supplements is increasing in recent times as potential agents in maintenance of health and the prevention and treatment of diseases. Matcha tea powder is obtained from the leaves of tea plant (Camellia sinensis (L.) Kuntze) grown under specific condition using about 90% shade. As compared to green tea, a hot water extract of tea leaves, matcha is consumed as a whole powder of leaves. Matcha powder is reported to have higher content of some bioactive components such as catechins, theanine and caffeine. In recent years, there is an increased market demand and consumption of matcha as a drink and as a component in various beverages, snacks and other food products. Scope and approach In this review, the available scientific information of the chemical constituents and their analysis and biological activities are critically analyzed. These results may help to understand current status of research on matcha and the gaps which help to guide future research related to evidence based product formulations. Key findings and conclusions Various studies have reported the difference in bioactive compounds in matcha as compared to green tea and other tea formulations. The content and composition were mostly affected by the cultivation and processing techniques. Analysis of marketed samples in various countries have shown the variable content of the bioactive compounds. Thus, there is a need for proper standardization for maintaining the quality. Matcha as a whole, its extract and compounds have shown promising biological activities in in vitro and animal studies. However, comparatively only a few clinical studies are performed, which need future attention. There should also be detailed study regarding matcha-containing foods’ formulation.
... Numerous studies have shown that the milling technique had impacts on matcha particle characteristics in terms of size, shape and structure, flowability and foam properties such as the foam's size and stability (Sawamura et al., 2009;Sawamura et al., 2010;Sawamura et al., 2012;Zhang et al., 2019). It had also been demonstrated that changes in the milling processes could result in changes in chemical components, in particular the concentration of catechins, in the matcha (Fujioka et al., 2016;Hu, Chen, & Ni, 2012;Zaiter, Becker, Karam, & Dicko, 2016). This indicates that the sensory performance of the differently-milled matcha could also be affected by changes in their physical properties, which impacts both the taste and the aroma of the product. ...
... The mean, median and d 90 (where 90% of the particles fall below this value) values for the particle size distribution were as follows: 8.93, 7.42 and 16.92 µm for cyclone-milled matcha; 19.57, 9.03 and 35.53 µm for bead-milled matcha; and 15.87, 8.65 and 27.56 µm for stone-milled matcha. The mean values of the particle size distribution recorded for stone-milled were within the range (15.0 to 18.3 µm) reported by Fujioka et al. (2016) and Sawamura et al. (2010) and Sawamura et al. (2012). From Fig. 2(a), a narrower distribution curve was observed for cyclone-milled matcha than bead-and stonemilled matcha. ...
... Apart from size difference, it was also visually observed that the surface of stone-milled matcha was uneven as compared to cyclone-and bead-milled matcha. Similar observations was reported by Fujioka et al. (2016) and Sawamura et al. (2010) where they recorded lower roundness and uneven surface of stone-milled matcha due to higher shearing force of the milling process. As such, the surface area and surface properties of matcha vary with the milling process applied. ...
Article
Analysis of three matcha (cyclone-, bead- and stone-milled) revealed differences in their sizes and surface morphologies. Using liquid chromatography, 4 sugars, 6 organic acids, 18 amino acids and 9 polyphenols were detected in all matcha samples and shown to present in different amount. Moreover, 108 volatile compounds were detected and 30 potential flavour-contributing compounds were quantified by gas chromatography time-of-flight mass spectrometry using headspace-stir bar sorptive extraction-thin-film solid-phase microextraction (HS-SBSE-TFSPME). Sensory evaluation by a trained panel found that the matcha samples possess different notes (cyclone-milled: leafy; bead-milled: fishy; and stone-milled: roasty) which is supported by the volatile compound analysis. Finally, the three matcha were differentiated based on non-volatile and volatile components using principal component analysis, and the correlation between chemical composition and sensory evaluation data was carried out using partial least square regression. In conclusion, milling processes clearly affected the physical, chemical and sensory qualities of matcha.
... In the case of both the methods, the antioxidant potential was higher at 90 • C and the lowest at 25 • C. This is because of the effective release of biologically active compounds and higher kinetic energy at higher brewing temperatures, as confirmed by other studies as well [63,70]. Matcha from the first and second harvest has lesser polyphenol contents, including rutin and vitamin C, and lower antioxidant potential (DPPH) than daily matcha originating from the second and third harvests. ...
... Matcha's high antioxidant potential is also visible in its powdered form. Fujioka et al. [70] proved that powdered tea, in comparison to leaf tea, has higher concentration of polyphenols. Komes et al. [63] tested 11 types of green tea and concluded that the powdered form (matcha) was characterized by the highest parameters out of all green tea types and required minimal brewing time. ...
... This was found to be significantly lower in the test-matcha group than in the placebo group. Fujioka et al. [70] published a study in 2016 in which they observed that the protective effect of matcha against oxygen radicals is significantly higher than the effect of normal tea leaves because of the elevated catechin levels matcha contains. The effects of green tea, matcha tea, and EGCG and quercetin on MCF-7 and MDA-MB-231 breast carcinoma cells demonstrate the anticancer activity of matcha that has been reported [70]. ...
Article
Full-text available
Matcha tea is a traditional Japanese tea that is said to possess ten times higher bioactive components and polyphenols than that of conventional green teas. Matcha is remotely popular among the global community and meagerly researched and infamous among the scientific population. It is the powdered form of green tea leaves that are directly suspended in hot water and drunk without filtration. Matcha is said to be one of the richest antioxidant sources naturally available. This review summarizes the available research publications related to matcha and compares the research accomplishments of green tea and matcha researchers. The fact that green tea is backed up by 35,000 publications while matcha has merely 54 publications to its credit is highlighted in this review for the first time. The future of matcha for tapping its enormous antioxidant activity and health potentials remains connected to the volume of scientific awareness and enhanced research attention in this area. If green tea has so much to offer towards human health and welfare, there is certainly room for more benefits from matcha, which is yet to be disclosed. As public awareness cannot be won without scientific approval, this review seeks that this gap may be bridged using essential knowledge gained from matcha applications and allied research.
... The grinding process is an important processing link in the production process of matcha and plays an important role in the formation of the quality of matcha. Numerous studies have shown that changes in the grinding process may lead to changes in the chemical composition of matcha, especially in the concentration of non-volatile components [33,39,51]. It has also been demonstrated that there are differences in aroma components between different milling processes (cyclone, bead and stone millings), and stone-milled matcha was perceived to be higher in roasted notes, containing a higher number of pyrazines [39]. ...
Article
Full-text available
Shandong matcha has the quality characteristics of bright green color, seaweed-like aroma and strong, fresh and brisk taste. In order to identify the characteristic aroma components and clarify the contribution of the grinding process to the aroma of Shandong matcha. Three grades of Shandong matcha and corresponding tencha material were firstly tested with sensory evaluation, and the volatile components were extracted with headspace solid-phase microextraction (HS-SPME) and solvent-assisted flavor evaporation (SAFE) and analyzed using GC–MS. The sensory evaluation results showed that high-grade matcha (M-GS) had prominent seaweed-like, fresh and roasted notes, whereas medium and low-grade matcha (M-G1, M-G2) were gradually coupled with grassy, fatty and high-fired aromas. GC–MS results showed that in the HS-SPME method, heterocyclic compounds (45.84–65.35%) were the highest in Shandong matcha, followed by terpenoids (7.44–16.92%) and esters (6.91–15.27%), while in the safe method, esters were the highest (12.96–24.99%), followed by terpenoids (10.76–25.09%) and heterocyclic compounds (12.12–17.07%). As a whole, the composition of volatile components between M-G1 and M-G2 is relatively close, and there are more differences in volatile components between them and M-GS. The volatile components unique to M-GS were screened using the odor activity value (OAV) evaluation method, with components such as 3-methyl-2-butene-1-thiol, 3-ethyl-Phenol, 2-thiophenemethanethiol, 2,4-undecadienal, (E,E)-2,6-nonadienal, (E,Z)- being evaluated. There were other differentially volatile components, that is, volatile components that coexist in the three grades of matcha, but with different concentrations and proportions. M-G1 and M-G2 contained more volatile substances with high-fired aroma, such as 2-ethyl-3-methyl-pyrazine, coumarin and 5,6,7,8-tetrahydroquinoxaline. The grinding process not only changes the appearance of tencha, but also increases the content of volatile components of matcha as a whole, enhancing the aroma and flavor characteristics of matcha. In this study, the contents of 24 volatile components in matcha were mainly increased, such as benzene, (2,2-dimethoxyethyl)-, cis-7-decen-1-al, safranal and fenchyl acetate. The dual factors of material tencha and matcha grinding technology are indispensable in forming the differences in aroma and flavor of Shandong matcha at different levels.
... In green teas, pyropheophytins ( Table 2) represented between 0.7 to 3%, correlating well with pheophytin content. As it has been proposed previously, pyropheophytins are probably formed during tea production when tea leaves are steamed to inactivate the endogenous enzymes [30]. In this line of thinking, the biochemical origin of the oxidized chlorophyll metabolites (13 2 -hydroxy-chlorophylls and pheophytins and 15 1 -hydroxy-lactone-pheophytins) is still under discussion. ...
Article
Full-text available
Green teas are nonfermented teas, the quality of which is measured by the green color. However, this category encompasses a high number of tea varieties that differ in cultivation and processing. For example, leaf or stem/bubble tea, plants cultivated under a light or shadow regime, powdered or unpowdered tea, etc. These variables determine the different qualities among green teas (Matcha, Sencha, Gyokuro, etc.) and consequently their different values on the market. Our purpose is to determine if these variables can exert an influence on the chlorophyll profile and to establish a characteristic profile for specific green teas. With such an aim, we analyzed the chlorophyll profiles of 6 different green tea varieties via HPLC-hr ESI/APCI–MS2 and identified up to 17 different chlorophyll compounds. For the first time, 132-hydroxy-chlorophylls, 132-hydroxy-pheophytins, and 151-hydroxy-lactone-pheophytins have been identified in green teas. Shadow teas (Matcha and Sencha) and light-regimen green teas can be statistically differentiated by the total chlorophyll content and the a/b ratio. However, only Matcha tea contains a higher proportion of chlorophylls a and b among the green tea varieties analyzed, justifying the higher quality and price of this variety. Other chlorophyll metabolites (pheophytins, pyropheophytins, and oxidized chlorophylls) are indicative of the various processing and storage conditions.
... [9] Matcha has higher catechin contents than other green teas, which was recently shown to manifest in a higher inhibition effect of reactive oxygen species production. [26] Therefore, we decided to use this particular kind of green tea for our investigations. ...
Article
Full-text available
Scope: Green tea is associated with decreased risk for cardiovascular disease and stroke. Matcha is a special kind of powdered green tea known for its use in the Japanese tea ceremony. Due to its influence on lipoprotein parameters, it has been postulated to exert antiatherogenic effects. We investigated whether it modulates the HDL function and thereby influences the atherogenic process in an animal model with a strong influence on humans' situation. Methods and results: After a pretreatment phase based on a standard diet, ten female NZW rabbits were fed a high-fat diet for 20 weeks. The treatment group was additionally administered 1% matcha during the whole experiment. Long-term matcha treatment led to lowered HDL cholesterol, impaired cholesterol transport manifested by reduced in vitro cholesterol efflux capacity, reduced CETP-mediated cholesterol ester (CE) transfer between HDL and triglyceride-rich particles, and reduced macrophage-specific in vivo transfer, where we observed increased absorption of cholesterol in the liver but a decreased secretion into bile. Pulse wave velocity, assessed by nuclear magnetic resonance, was increased in matcha-treated animals, and a similar trend was observed for atherosclerotic lesion formation. Conclusion: Long-term matcha green tea treatment of hypercholesterolemic rabbits caused impaired reverse cholesterol transport and increased vascular stiffness, and susceptibility for atherosclerotic lesion development. This article is protected by copyright. All rights reserved.
... On the other hand, exposure for too long to high temperature may lead to the degradation of polyphenolic compounds, thus reducing their antioxidant potential. Fujioka et al. [30] showed that ground teas do not require long brewing, because from this form, biologically active compounds are faster and easier to extract, which is also confirmed by the results obtained in this study. ...
Article
Full-text available
The polyphenol content of tea depends on the growing region, harvest date, the production process used, and the brewing parameters. In this study, research was undertaken that included an analysis of the influence of the brewing process parameters on the content of total polyphenols (Folin-Ciocalteu), epigallocatechin gallate (HPLC), and antioxidant activity (against DPPH radicals) of fresh tea shrub leaves grown from Taiwan and of teas obtained from them (oolong, green in bags, and green loose from the spring and autumn harvest). The antioxidant potential was determined in the methanol and aqueous extracts, as well as in infusions that were obtained by using water at 65 or 100 °C and infusing the tea for 5 or 10 min. The highest content of total polyphenols and epigallocatechin gallate was found in green tea extracts from the spring harvest. However, in the case of infusions, the highest content of these compounds was found in green tea in bags. Steaming at 100 °C for 10 min, turned out to be the most favourable condition for the extraction. Oolong tea, brewed at 100 °C for 5 min was characterised by the highest antioxidant activity against stable DPPH radicals.
... The amount of catechins was different depending on the brewing temperature and time [25,26]. Similar to our finding, Fujioka et al. [27] reported that loose leaf tea had about a three-fold lower amount of catechins than powdered tea prepared in the traditional brewing manner (1 g/80 mL). It is plausible that the drinking usage for powdered tea could be preferred by consumers rather than loose leaf tea in terms of the contents of total epicatechins. ...
Article
Full-text available
The aim of this study was to profile the bioaccessibility and intestinal absorption of epicatechins and flavonols in different forms of green tea and its formulation: loose leaf tea, powdered tea, 35% catechins containing GTE, and GTE formulated with green tea-derived polysaccharide and flavonols (CATEPLUS™). The bioaccessibillity and intestinal absorption of epicatechins and flavonols was investigated by using an in vitro digestion model system with Caco-2 cells. The bioaccessibility of total epicatechins in loose leaf tea, powdered tea, GTE, and CATEPLUS™ was 1.27%, 2.30%, 22.05%, and 18.72%, respectively, showing that GTE and CATEPLUS™ had significantly higher bioaccessibility than powdered tea and loose leaf tea. None of the flavonols were detected in powdered tea and loose leaf tea, but the bioaccessibility of the total flavonols in GTE and CATEPLUS™ was 85.74% and 66.98%, respectively. The highest intestinal absorption of epicatechins was found in CATEPLUS™ (171.39 ± 5.39 ng/mg protein) followed by GTE (57.38 ± 9.31), powdered tea (3.60 ± 0.67), and loose leaf tea (2.94 ± 1.03). The results from the study suggest that formulating green tea extracts rich in catechins with second components obtained from green tea processing could enhance the bioavailability of epicatechins.
Article
Matcha is a powdered form of Japanese green tea that has been gaining global popularity recently. Matcha tea has various health benefits, including an enhancing effect on cognitive function, cardio-metabolic health, and anti-tumorogenesis. To date, randomized clinical trials (RCT) showed that matcha decreases stress, slightly enhances attention and memory, and has no effect on mood. Results regarding the effect of matcha on cognitive function are contradictory and more RCTs are warranted. The cardio-metabolic effects of matcha have only been studied in animals, but findings were more homogenous. Consuming matcha with a high-fat diet resulted in decreased weight gain velocity, food intake, improved serum glucose and lipid profile, reduced inflammatory cytokines and ameliorated oxidative stress. Evidence regarding the anti-tumor function of matcha is very limited. Findings showed that matcha can affect proliferation, viability, antioxidant response, and cell cycle regulation of breast cancer cells. Nonetheless, more studies are needed to examine this effect on different types of cancer cells, and there is also a need to verify it using animal models. Overall, the evidence regarding the effect of matcha tea on cognitive function, cardio-metabolic function, and anti-tumor role is still limited, and conclusions cannot be drawn.
Article
People’s interest in green tea powder is increasing currently. The addition of green tea powder to food products could increase antioxidant activity and other health benefits. GMB 7 and GMB 9 are local tea clones of the Assam variety widely planted in Indonesia’s tea plantation. This study aimed to determine green tea powder’s total polyphenols and antioxidant activity from local tea clones (GMB 7 and GMB 9). Total polyphenol and antioxidant activity were determined by Folin-Ciocalteau and free radical of DPPH methods, respectively. Our results showed that the total polyphenols of green tea powder were 27.61% and 27.31% for the GMB 7 and GMB 9 clones, respectively. Furthermore, the antioxidant activity of green tea powder with IC50 was 15.41 mg/L and 17.32 mg/L for clones GMB 7 and GMB 9, respectively. The results indicate the potential for the development and utilization of local clones to fulfill domestic green tea powder production. Further research is needed to determine the health benefits of green tea powder from clones of The Assam varieties.
Article
Full-text available
Obesity and being overweight are linked with a cluster of metabolic and vascular disorders that have been termed the metabolic syndrome. This syndrome promotes the incidence of cardiovascular diseases that are an important public health problem because they represent a major cause of death worldwide. Whereas there is not a universally-accepted set of diagnostic criteria, most expert groups agree that this syndrome is defined by an endothelial dysfunction, an impaired insulin sensitivity and hyperglycemia, dyslipidemia, abdominal obesity and hypertension. Epidemiological studies suggest that the beneficial cardiovascular health effects of diets rich in green tea are, in part, mediated by their flavonoid content, with particular benefits provided by members of this family such as epigallocatechin gallate (EGCG). Although their bioavailability is discussed, various studies suggest that EGCG modulates cellular and molecular mechanisms of various symptoms leading to metabolic syndrome. Therefore, according to in vitro and in vivo model data, this review attempts to increase our understanding about the beneficial properties of EGCG to prevent metabolic syndrome.
Article
We have developed a quantitative assay to monitor the oxidative burst (H202 production) of polymorphonuclear leukocytes (PMNL) using single cell analysis by flow cytometry, and have examined whether PMNL respond to membrane stimulation with an all-or-none oxidative burst. During incubation with normal neutrophils, dichlorotJu-orescin diacetate diffused into the cells, was hydrolyzed to 2′,7′-dichlorofluorescin (DCFH) and was thereby trapped within the cells. The intracettular DCFH, a nonfluores-cent fluorescein analogue, was oxidized to highly fluorescent 2',7'-dichlorofluorescein (DCF) by PMNL stimulated by phorbol myristate acetate (PMA). That the oxidative product was DCF was shown by excitation/emission spectra and by mass spectrometry of the product from PMA-stimulated PMNL. Normal resting and PMA-stimu-lated PMNL oxidized 6.9 ± 0.7 and 160 ± 13 attomoies DCF per cell, respectively, in 15 min. Absence of calcium and magnesium ions and/or addition of 2 mM EDTA did not inhibit DCF formation by PMNL stimulated by 100 ng/ ml PMA. Since EDTA prevented aggregation of PMNL (even when stimulated by 100 ng/ml PMA), which would prevent accurate flow cytometric analysis, further experiments were performed with EDTA in the medium. A close correlation between average DCFH oxidation and hexose monophosphate shunt stimulation was demonstrated using cells from patients whose PMNL had oxidative metabolic defects of varying severity. Intracellular DCFH was also oxidized by reagent H202 or oxygen derivatives generated by glucose oxidase + glucose or by xanthine oxidase + acetaldehyde; DCFH oxidation by these systems was inhibited by catalase but unchanged by superoxide dismutase. The data indicate that the DCFH oxidation assay is quantitatively related to the oxidative metabolic burst of PMNL, and they strongly suggest that the reaction is mediated by H2Qi generated by the PMNL. Incubation of PMNL with varying concentrations ot PMA caused graded responses by all PMNL present; i.e., 1 ng/ ml PMA caused a mean response of 34% maximal with a single population of responding PMNL (rather than 66% resting and 34% fully stimulated as predicted by the all-or-none hypothesis). Thus, with these assay conditions, oxidative product formation by PMNL occurs as a graded response to membrane stimulation by PMA.
Article
The molecular mechanism by which tea polyphenols decrease the micellar solubility of cholesterol is not completely clear. In order to clarify this mechanism, we investigated the interaction between tea polyphenols (catechins and oolongtheanins) and cholesterol micelles. A nuclear magnetic resonance (NMR) study was performed on a micellar solution containing taurocholic acid and epigallocatechin gallate (EGCg), and high performance liquid chromatography (HPLC) analysis was carried out on the precipitate and the supernatant that formed when EGCg was added to a cholesterol-micelle solution. The data indicated a regiospecific interaction of EGCg with taurocholic acid. Therefore, the ability of EGCg to lower the solubility of phosphatidylcholine (PC) and cholesterol in micellar solutions can be attributed to their elimination from the micelles due to interaction between taurocholic acids and EGCg.
Article
Adzuki bean (Vigna angularis) contains abundant polyphenols, and their anti-oxidant effects have attracted the attention of many researchers. Although the effects of uncooked Adzuki beans and Adzuki bean juice have been reported, the effects of Adzuki bean pastes (sweet red bean paste) have not yet been clarified. Since sweet red bean pastes are easily incorporated into the diet as desserts or snacks, we investigated the polyphenol content and reactive oxygen species (ROS) inhibitory activity of the pastes. From these results, the sweet red bean pastes contained 37. 1-62. 7 mg of polyphenols per 100 g of bean paste, and exhibited superoxide dismutase (SOD) -like activity and ROS inhibitory effects in Jurkat cells. (In Japanese)
Article
The production of Matcha for processed food is increasing in recent years. However, Matcha has many problems for use in processed food, such as bad suspension, color deterioration, and high costs. We developed fine Matcha to overcome these problems, and investigated its properties. Fine Matcha was produced by two methods : classification of normal Matcha, and crushing by jet-mill. The particle size of normal Matcha ranges widely from 1 μm to 100 μm, but that of fine Matcha has a narrow range of from 1 μm to 20 μm. The particle diameter of fine Matcha is 3.2 μm, and that of normal Matcha is 11.5 μm. Fine Matcha suspended in water has a smaller sedimentation rate than normal Matcha. In addition, fine Matcha used in buckwheat noodles (soba noodles) improved the colorimetry of the noodles in comparison with normal ones. Finally, fine Matcha added to dough was found to cause the bread to rise better than normal. Thus, fine Matcha is useful for processed food in producing less sedimentation, improving the colorimetry, and augmenting the rising of bread dough.
Article
(1) (-)-エピカテキン(EC), (-)-エピガロカテキン(EGC),(-)-エピカテキンガレート(ECg), (-)-エピガロカテキンガレート(EGCg)のラードにおける抗酸化作用を調べた.ラードにおける抗酸化力は等重量濃度で比べた場合, ECg<EC<EGCg<EGCとなり, BHAおよびdl-α-トコフェロールよりも強い抗酸化作用を示した.また等モル濃度で比べた場合はEC<ECg<EGC<EGCgとなり,構造式との相関関係があるように思われる. (2) EGCgとアミノ酸を併用したラードはEGCgのみのものに比べると,むしろPOVを上げるもののほうが多く, 19種アミノ酸のうちL-メチオニンのみがわずかに相乗作用を示した.リンゴ酸,酒石酸およびクエン酸が相乗作用を示した.またL-アスコルビン酸およびトコフェロールもEGCgと強い相乗作用を示した. (3) リノール酸に対してもEGCgは抗酸化作用を示したが,その強さはラードにおけるそれよりも弱かった.また水添加リノール酸に対しても抗酸化作用を示し,油系のみならず,水系においても抗酸化作用を発現することがわかった. (4) カテキン混合物(総カテキン含量約72%)は,ラードにおいてはEGCg単独の抗酸化力と同等の効力を示した,またこれはトコフェロール含有の市販サラダ油に対しても顕著な抗酸化作用を発揮することが明らかになった.
Article
Background and Purpose: We examined the association between green tea consumption and mortality due to all causes, cancer, heart disease, cerebrovascular disease, respiratory disease, injuries and other causes of death in a large-scale population-based cohort study in Japan. Methods We studied 90,914 Japanese (aged between 40 and 69 years) recruited between 1990 and 1994. After 18.7 years of follow-up, 12,874 deaths were reported. The association between green tea consumption and risk of all causes and major causes of mortality was assessed using the Cox proportional hazards regression model with adjustment for potential confounders. Results Hazard ratios for all-cause mortality among men who consumed green tea compared with those who drank less than 1 cup per day were 0.96 (0.89 to 1.03) for 1 to 2 cups per day, 0.88 (0.82 to 0.95) for 3 to 4 cups per day, and 0.87 (0.81 to 0.94) for more than 5 cups per day (p for trend <0.001). Corresponding hazard ratios for women were 0.90 (0.81 to 1.00), 0.87 (0.79 to 0.96), and 0.83 (0.75 to 0.91) (p for trend <0.001). Green tea was inversely associated with mortality from heart disease in both men and women, and mortality from cerebrovascular disease and respiratory disease in men. No association was found between green tea and total cancer mortality. Conclusion This prospective study suggests that the consumption of green tea may reduce the risk of all-cause mortality and the three leading causes of death in Japan.
Article
Chemical compositions of various grades of Mat-cha (5000, 4000, 3000, 2000, and 1000 yen/40g) were determined.Contents of total nitrogen, caffeine and free amino acids and an amide (theanine) were decre ased with decreasing the price of Mat-cha.Vitamine C contents of these were lower than that of Sen-cha, and Vitanine C contents of high grade Mat-cha (>3000 yen/40g) were higher than those of low grade Mat-cha (<2000 yen/40g).Contens of free reducing suggar and vitamine E were not different amang Mat-chas.Free arginine, asparatic acid, glutamic acid, threonine and theanine (amide) in Mat-cha were decreased with decreasing the price of Mat-cha.