Chemical Components of Matcha and Powdered Green Tea

日本調理科学会誌 Vol.日本調理科学会誌 Vol. 50，No. 5，182～188（2017） 50 No. 5（2017）〔Note〕

Hideki Horie*§ Kaori Ema* Osamu Sumikawa**

Matcha is a type of powdered tea; it was previously regarded as a precious beverage and is served at tea ceremonies in Japan. Today, powdered teas labeled “matcha” are used in the food industry as well as in cooking; both are referred to as industrial-grade matcha in this report. Moreover, powdered green teas that are not labeled as “matcha” are also sold in the market. However, there is little information on the quality of these powdered teas. There- fore, in this study, we compared the chemical components of “matcha” and powdered green tea. Ten grades of Tencha（milled Tencha is matcha） were collected and their chemical components were analyzed. Based on the results, the contents of theanine and chlorophyll a（Chl- a） and the ratio of epigallocatechin gallate/epigallocatechin （EGCG/EGC） were compared among the powdered teas sold on the market. Tea ceremony-grade matcha was found to contain ＞1.8 g/100 g DW of theanine and exhibited an EGCG/EGC ratio ＞3.2（weight-based）. Most industrial-grade matcha and powdered green tea samples exhibited lower values; however, it was difficult to distinguish industrial-grade matcha from powdered green tea by using only these parameters. The Chl-a content of matcha for tea ceremonies was more than 250 mg/100 g DW. Powdered green tea samples, except for Gyokuro powders, exhibited low Chl-a contents relative to both ceremonial and industrial grade matcha samples.

Keyword：high-performance liquid chromatography, quality evaluation, Tencha, food industry, cooking

duction of this tea is estimated to be ＞3,800 t in Japan INTRODUCTION （Kuwabara, 2016）. Powders prepared from tea leaves are Several types of green tea are produced in Japan. Chu often found in food products including cakes, noodles, and （1997） reported the production procedure for several ice creams. As mentioned above, authentic matcha is the types of green tea. Sencha, the most popular tea in Japan, powdered tea from “Tencha” and is used for tea ceremo- is produced as follows. Harvested tea leaves are steamed nies; however, so-called “matcha” is popularly used as a to inactivate the enzymes present in the leaves and subse- food ingredient. These “matcha” teas are sold as “matcha quently, rolled and dried. On the other hand, matcha is a for cooking” or “matcha for the food industry”. Moreover, powdered tea for tea ceremonies and is produced from “powdered green tea” is also sold as a food ingredient or shaded leaves. The shading process is important and for drinking. Powdered green tea is the powder of Sencha affects the quality of matcha. Shade treatment prior to or green teas other than Tencha. Several kinds of pow- harvest is known to increase the amino acid and caffeine dered teas, namely authentic matcha for tea ceremonies, contents and decrease the catechin content（Saijo, 1999）. matcha for ingredients, and powdered green tea, are pro- In authentic matcha production, the steamed leaves are duced and circulated in Japan. These teas all look similar, dried without rolling using a special drier called a so it is not easy to differentiate them intuitively. There is Tencha-ro. The dried leaves are called “Tencha” and pow- little information on the chemical components of powdered dered Tencha ground with exclusive stone mills is termed teas other than authentic matcha. Thus it is interesting to matcha. Gyokuro is another high-quality tea with a manu- compare the components in these different teas. facturing process similar to that of Sencha; however, In this study, we compared the chemical components of shaded leaves are used for the production of Gyokuro authentic matcha and other powdered green tea samples （Tokunaga, 2004）. available from local markets. Before comparing matcha Consumption of green tea as a beverage used to be and other teas, we analyzed Tencha samples to determine very popular in Japan; use of green tea as a food ingredi- the chemical indicators. As several lots of Tencha are ent, however, has rapidly increased recently and the pro- blended and milled into commercial matcha, the prices of Tencha directly reflect the quality of the tea itself. The * Institute of Fruit Tree and Tea Science, NARO ** National Agriculture and Food Research Organization most important components of Japanese green tea are § Inquiry Division of Tea Research, Institute of Fruit Tree and Tea Sci- catechins, caffeine, and amino acids（Goto et al., 1996）. ence, NARO The bitter and astringent taste of tea is attributed to cat- 2769 Kanaya-Shishidoi, Shimada, Shizuoka 428-8501, Japan E-mail：[email protected] echins, while the umami taste is attributed to amino acids.

16 （182） Chemical Components of Matcha and Powdered Green Tea

Caffeine is a stimulant that acts on the central nervous prised Gyokuro powder while samples I, J2, and J3 were system and is abundant in high-quality teas （Chu & Sencha powders. On the other hand, there was no indica- Juneja, 1997）. The content of four major catechins, epigal- tion of the nature of the tea on the label of sample H. All locatechin gallate（EGCG）, epigallocatechin（EGC）, epicat- the teas were used for the analysis without any further echin gallate（ECG）, and epicatechin（EC）, as well as caf- preparation. feine, was analyzed using high-performance liquid chromatography （HPLC）. Seven major amino acids, Analytical methods namely aspartic acid（Asp）, glutamic acid（Glu）, aspara- The catechin and caffeine contents of the tea powders gine（Asn）, serine（Ser）, glutamine（Gln）, arginine（Arg）, were measured using an HPLC system（Shimadzu, LC- and theanine, were also analyzed using HPLC. Theanine is 10ADvp） according to previous reports （Maeda- a unique amino acid that constitutes almost half of the Yamamoto et al., 2004, Maeda-Yamamoto et al., 2005）. total amino acids in green teas（Chu & Juneja, 1997）. On Briefly, 250 mg of powdered tea sample were extracted the other hand, the green color of the leaf powder in with 25 mL of a 2％ phosphoric acid/ethanol（1:1） mix- matcha and powdered green teas is also important ture at 30℃ for 60 min. The filtrate was diluted with （Tokunaga, 2004）. Tachibana and Shoyama（1979） previ- water and injected into the HPLC system. The conditions ously reported the relationship between leaf color and for the reversed-phase HPLC analysis have been chlorophyll content; therefore, in this study, we evaluated described in the literature（Maeda-Yamamoto, 2005）. the content of chlorophyll and related components using For the analysis of free amino acids, 100 mg of pow- HPLC. dered tea were extracted with 10 mL of distilled water at 80℃ for 30 min. The resultant filtrate was collected and MATERIALS AND METHODS used for further analysis. The free amino acids were ana- Tea samples lyzed using HPLC（Shimadzu, LC-20AD） connected to an Ten grades of “Tencha” were purchased from a well- auto-injector（SIL-30AC）. A pre-column derivatization established matcha company in Uji, Kyoto, Japan（Sample method, using o-phthalaldehyde, was employed and the Set 1, Table 1）. The Tencha samples were powdered Table 2. Matcha and powdered green tea samples（Sample Set using the exclusive stone mill for matcha at the company. 2） Matcha and powdered green tea samples were pur- Price chased from tea companies（Sample Set 2, Table 2）; some Sample* Use （Yen/100 g） teas were labeled “matcha for the food industry” or B1 Matcha tea ceremony 8,100 “matcha for cooking,” and one matcha for cooking（G） B2 Matcha tea ceremony 4,320 B3 Matcha cooking 1,890 indicated the addition of chlorella. In this report, the B4 Matcha food indusutry 1,468 matcha samples for cooking or the food industry are B5 Matcha food indusutry 1,292 treated as “industrial grade” and other matcha samples C Matcha cooking 972 D1 Matcha tea ceremony 6,250 used just for drinking are described as “ceremonial grade.” D2 Matcha tea ceremony 3,750 Among the powdered green tea samples, sample J1 com- D3 Matcha tea ceremony 3,250 E1 Matcha tea ceremony 4,280 Table 1. Tencha sampels（Sample Set 1） E2 Matcha food indusutry 1,500 E3 Matcha food indusutry 1,050 Price plucking E4 Matcha food indusutry 630 Sample （Yen/kg） season method F1 Matcha food indusutry 950 A1 30,000 first* hand F2 Matcha food indusutry 600 A2 15,000 first hand G Matcha cooking** 1,400 A3 10,000 first hand + plucker H Powdered Green Tea 580 A4 7,500 first plucker I Powdered Green Tea*** 300 A5 6,000 first plucker J1 Powdered Green Tea**** 560 A6 4,500 first plucker J2 Powdered Green Tea*** 200 A7 3,000 first + second plucker J3 Powdered Green Tea*** 170 ** A8 2,500 second plucker *: The same letter indicate the samples are bought from the A9 2,000 second plucker same company. *** A10 1,000 autumn plucker **: Chlorella is mixed wih matcha. * First crop, ** Second crop ***: Powder of Sencha. *** Harvested in autumn without shading. ****: Powder of Gyokuro.

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instrument manufacturer guidelines were followed. A tea companies. Tencha samples of known origins and reversed phase column（GL Sciences, Inesrtsil ODS-4, 5 grades were purchased from a reliable tea company. μm, 4.6 mm × 250 mm） was employed. Mobile phases A Among the Tencha samples listed in Table 1, A1 was of and B were 20 mM potassium phosphate buffer （pH 6.4） the highest grade; the grade decreased in numerical order, and a water/acetonitrile/methanol （15/45/40 V/V/V） with A10 being the lowest. Tencha from the first crop is mixture, respectively. The linear gradient elution was per- more valuable than that of the second crop and hand- formed as follows: 10％ mobile phase B for the first 3 min, plucked teas are of higher quality than those obtained via programed to 30％ mobile phase B for 27 min; 40％ mechanical plucking. Matcha is usually made from shaded mobile phase B for the next 0.5 min, maintained at 40％ leaves, whereas the lowest-grade tea, A10, was made mobile phase B for 3.5 min; and finally, back to 10％ from non-shaded leaves. mobile phase B. The seven major amino acids（Asp, Glu, The amino acid contents were compared in Table 3a. Asn, Ser, Gln, Arg, and theanine） were analyzed with gly- Higher-grade teas contained greater amounts of total cylglycine as internal standard（Goto et al., 1993）. amino acids, theanine, and other individual amino acids. In The color pigments chlorophyll a（Chl- a）, chlorophyll b the literature, high-grade green teas including matcha are （Chl-b）, pheophytin a（Phy- a）, and pheophytin b（Phy- rich in amino acids（Goto et al., 1996）. Tsuji（2001） sug- b） were analyzed using HPLC（Shimadzu, LC-10ADvp） gested that the total amino acid content could be used as connected to a column（Tosoh, TSKgel ODS-80TM, 5 μm, a quality indicator for Tencha. Our results also indicated 4.6 mm × 150 mm）. The sample solution for the analysis that the total amino acid or theanine contents would be of these pigments was prepared as follows: 100 mg of good indicators for the quality of Tencha. powdered tea were extracted with 10 mL of 85％ acetone On the other hand, the high-grade teas contained lower by centrifugation. The resultant supernatant was trans- amounts of total catechins than lower-grade teas（Table ferred to a 25 mL volumetric flask. The precipitate was 3b）. Goto et al. （1996） also reported that high-grade reextracted with 10 mL of 85％ acetone and the superna- matcha contained a lower total catechin content than low- tant was added to the contents in the volumetric flask. grade matcha. Moreover, the EGC and EC contents were Subsequently, 85％ acetone was added to fill to the 25 mL greater in lowergrade teas, while those of EGCG and ECG mark. HPLC analysis was performed according to the pro- did not seem to correlate with tea grade（Table 3b）. It is cedure described by Kohata et al.（1998）. well known that younger leaves of tea shoots contain less Each analysis was repeated and the average analytical EGC or EC than older leaves（Miwa et al., 1978） and data were described as dry weight-based in the tables strong shade treatment decreases the EGC and EC con- and figures. tents （Saijo & Osawa, 1981; Wang et al., 2012）. High- grade green teas are made from younger leaves and shad- RESULTS AND DISCUSSION ing is a requirement for the production of matcha. The Chemical components of Tencha EGC or EC contents may be an indicator of the quality of Matcha sold on the market is powdered tea that is matcha. The analysis of EGC is easier than that of EC blended and milled from several lots of Tencha by various because tea leaves are rich in the former. Thus it seems

Table 3a. Free amino acids contents in Tencha（Sample Set 1, n＝2） g/100 g DW Sample Asp Glu Asn Ser Gln Arg Theanine total-A* A1 0.79 0.87 0.22 0.13 0.43 1.50 3.43 7.36 A2 0.76 0.89 0.16 0.08 0.10 1.14 2.85 5.99 A3 0.70 0.78 0.16 0.08 0.12 1.09 3.01 5.94 A4 0.55 0.73 0.10 0.08 0.11 0.82 2.81 5.19 A5 0.52 0.55 0.12 0.09 0.08 0.54 2.36 4.24 A6 0.45 0.45 0.08 0.07 0.10 0.33 1.73 3.21 A7 0.38 0.35 0.08 0.06 0.08 0.24 1.20 2.39 A8 0.33 0.30 0.09 0.08 0.07 0.20 1.08 2.16 A9 0.33 0.31 0.08 0.08 0.06 0.21 1.14 2.22 A10 0.18 0.27 0.01 0.03 0.07 0.03 0.49 1.08 * Total of Asp, Glu, Asn, Ser, Gln, Arg and Theanine. Asp: aspartic acid, Glu: glutamic acid, Asn: asparagine, Ser: serine, Gln: glutamine, Arg: arginine.

18 （184） Chemical Components of Matcha and Powdered Green Tea

Table 3b. Catechins and caffeine in Tencha （Sample Set 1, n＝3） g/100 g DW Sample EGC EC EGCG ECG Caffeine total-C* EGCG/EGC A1 0.70 0.33 6.62 1.44 4.58 9.08 9.50 A2 1.17 0.38 5.76 1.18 3.80 8.50 4.91 A3 1.16 0.40 5.69 1.18 3.62 8.44 4.89 A4 1.55 0.48 6.73 1.47 4.05 10.23 4.33 A5 1.78 0.43 6.61 1.18 3.46 10.01 3.71 A6 2.13 0.52 7.05 1.28 3.65 10.97 3.32 A7 2.45 0.56 7.10 1.24 3.51 11.36 2.90 A8 3.03 0.65 7.10 1.21 3.64 11.99 2.34 A9 2.59 0.62 7.47 1.37 3.70 12.06 2.89 A10 4.71 0.98 5.81 1.05 1.68 12.55 1.23 * Total of EGC, EC, EGCG, ECG.

Table 3c. Chlorophylls and pheophytins in Tencha（Sample relationship between tea quality and the contents of these Set 1, n＝2） components. In their report, the Chl-a contents of matcha mg/100 g DW Sample samples were greater than those of Gyokuro or Sencha Chl-a Chl-b Pheo-a Pheo-b samples and higher-grade matcha samples were rich in A1 558 207 132 6 A2 694 256 180 10 Chl-a. Therefore, the Chl-a content indicates the quality A3 738 273 197 11 of Tencha or matcha samples, in spite of some exceptions A4 696 264 194 10 such as A1 or A2. Since it has been reported that exces- A5 633 251 231 13 A6 579 245 241 13 sive shading decreases the chlorophyll content（Kobayashi A7 508 218 238 12 et al., 2011）, the relatively lower Chl-a amounts in A1 and A8 453 216 289 16 A2 were likely related to the strong shading used to culti- A9 366 172 253 14 A10 116 61 184 5 vate high-quality Tencha. Chl-a: Chlorophyll a, Chl-b: Chlorophyll b, Pheo-a: Pheophytin a, Kohata et al.（1999） also reported that the pheophytin Pheo-b: Pheophytin b. content（Phy- a and Phy-b） in high-grade matcha was lower than that of low-grade matcha. However, in this feasible to estimate the quality based on EGC content. study, the lowest-grade sample A10 contained as much However, it is technically possible to mix the powders of pheophytin content as the second highest-grade sample, the leaves of some catechin-less plants or algae（as with A2. A10 was harvested in autumn without shading and G in Table 2） with those of matcha; the EGC content the chlorophyll content was extremely low in this sample should be low in such teas. Since the EGCG content did set. Since pheophytins are the degradation products of not exhibit any correlation with the quality of the teas in chlorophylls, the low pheophytin content in A10 was this sample set, we concluded that the EGCG/EGC ratio caused by the low chlorophyll content. It is difficult to use reflected the quality of matcha more effectively than the the contents of pheophytin as an indicator of grade among EGC or total catechin contents（Table 3b）. samples with a wide range of quality. Caffeine contents are also compared in Table 3b. The Chemical components of matcha and powdered green tea relationship between the grade of Tencha and caffeine Sample Set 1 comprised Tencha whose quality was contents seemed low; however, it is notable that the caf- determined by specialists. Usually several lots of Tencha feine content of A10（harvested in autumn without shad- are blended and milled to matcha. Teas sold as “matcha” ing） was extremely low among these samples. and “powdered green tea” in the market were collected as The chlorophylls and pheophytins contents are listed in Sample Set 2 and are listed in Table 2. The same letters Table 3c. The highest-grade Tencha samples, A1 and A2, in the table show that the tea samples were sold at the did not contain the greatest amounts of Chl-a or Chl-b; same company and the use（for tea ceremonies, cooking, however, the chlorophyll contents were greater in the or the food industry） labeled on the samples is shown in higher-grade teas among samples A3 to A10. Kohata et the table. The sizes of the packages collected were differ- al.（1999） analyzed chlorophylls and pheophytins in four ent among the samples, thus the prices in Table 2 are types of green tea sold on the market and discussed the quoted per 100 g. The prices of matcha were ＞600 Yen

（185） 19 日本調理科学会誌 Vol. 50 No. 5（2017） and those of the matcha for tea ceremonies were ＞3,000 were ＜3.3. The matcha for tea ceremonies could be Yen. On the other hand, those of powdered green tea characterized by the high contents of theanine and the were ＜600 Yen. high EGCG/EGC ratios. On the other hand, it was not According to the results of sample set 1, higher-grade easy to distinguish between the industrial-grade matcha Tencha contains higher amounts of theanine. The theanine and powdered green tea by using these parameters. contents of matcha and powdered green tea samples were Chl-a contents are compared in Fig. 1c. Those of cere- compared（Fig. 1a）. The teas with higher prices showed monial-grade matcha samples were higher than 250 high contents of theanine; the contents in matcha for tea mg/100 g DW, while those of powdered green tea sam- ceremonies were ＞1.8 g/100 g DW. The industrial-grade ples, except J1, were less than 60 mg/100 g DW. The matcha and powdered green teas had contents ＜1.7 powdered tea sample J1 was labeled as powdered g/100 g DW. Gyokuro. Gyokuro is cultivated under the shade like We hypothesized in the previous section that EGCG/ matcha, so the chemical constituents are expected to EGC rates would reflect the quality of matcha. The resemble those of matcha. In Fig. 1a and 1b, the content of EGCG/EGC ratios（weight-base） are displayed in Fig. 1b. theanine and the rate of EGCG/EGC of J1 were higher The samples of matcha for tea ceremonies exhibited than those of the other powdered green tea samples. On ratios ＞3.2, while ratios exhibited by the other teas the other hand, the contents of Chl-a of industrial-grade matcha were divided into two groups: contents of more 3 than 660 mg/100 g DW（shown as B3, B4, and B5 in Fig. 3） and less than 260 mg/100 g DW. It has been reported that chlorophylls are fragile in the manufacturing process. 2 Samples B3–B5 were produced in the same company, so J1 it can be supposed that the process of manufacturing of these teas is different from that of the other industrial- 1 grade matcha teas. The contents of Chl-a of industrial-

theanine (g/100theanine g DW) grade matcha samples were higher than those of pow-

0 dered green tea samples, although there was one 0 2000 4000 6000 8000 10000 exception: powdered Gyokuro（J1）. Since Chl-a contenst Price (Yen/100 g) is related to the green color of the tea powder, matcha

Fig. 1a. Relationship between the prices and the contents of （both ceremonial and industrial grades） is expected to be theanine in matcha and powderd green tea（Sample Set 2, recognized as the tea powder with the strongest green n＝2） color by the tea companies. ●：ceremonial grade, △：industrial grade, ■：powdered tea In our results, samples of matcha for tea ceremonies were characterized by high contents of theanine（＞1.8 7

6 900 5 800 B5 B4 B3 700 4 600 /E GC 3 J1 500

EGCG 400

2 g DW) (mg/100 300 J1 200 1 Chl- a G 100 0 0 0 2000 4000 6000 8000 10000 0 2000 4000 6000 8000 10000 Price (Yen/100g) Price (Yen/100 g)

Fig. 1b. Relationship between the prices and the rate of EGCG/ Fig. 1c. Relationship between the prices and the contents of EGC in matcha and powderd green tea（Sample Set 2, n＝ Chlorophyll a in matcha and powderd green tea（Sample 3） Set 2, n＝2） ●：ceremonial grade, △：industrial grade, ■：powdered tea ●：ceremonial grade, △：industrial grade, ■：powdered tea

20 （186） Chemical Components of Matcha and Powdered Green Tea g/100 g DW）, and high ratios of EGCG/EGC（＞3.2）. On composition of commercially available Japanese green tea, the other hand, for the industrial-grade matcha samples Foods Food Ingredients J., 170, 46-52 Kobayashi, E., Nakamura, Y., Suzuki, T., Oishi, T. and Inaba, K. and powdered green teas, the theanine contents and （2011）, Influence of light intensities on the color and ingre- EGCG/EGC ratios were ＜1.7 g/100 g DW and 3.3, dients of new shoots in tea plants, Tea Res. J.（in Japanese）, respectively. The contents of Chl-a of matcha for tea cer- 111, 9-41 emonies were ＞250 mg/100 g DW and of most of the Kohata, K., Hanada, K. and Horie, H.（1998）, High performance chromatographic determination of pheophorbide-a and its other samples were ＜260 mg/100 g DW. It is hypothe- related chlorophyll derivatives in tea leaves, Food Sci. Tech- sized that the matcha for tea ceremonies can be charac- nol. Int. Tokyo, 4, 80-84 terized with minimum contents of theanine and Chl-a and Kohata, K., Yamashita, Y., Yamauchi, Y. and Horie, H.（1999）, a minimum ratio of EGCG/EGC. It will be necessary to Investigations of qualities and properties of commercially available green teas on the basis of chlorophyll and its compare the analytical data of hundreds of matcha and derivatives contents, Tea Res. J.（in Japanese）, 87, 13-19 powdered teas before determining the minimum values Kuwabara, H. （2016）, O-Matcha no subete （All about necessary to distinguish ceremonial-grade matcha. Matcha） , The Tea（in Japanese）, 69, 18-23 Although we could not find any difference between the Maeda-Yamamoto, M., Nagai, H., Asai, K., Moriwaki, S., Horie, H., Kohata, K., Tachibana, H., Miyasa, T. and Sano, M. theanine contents and EGCG/EGC ratios of industrial- （2004）, Changes in epigallocatechin-3-O-（3-O-methyl） gal- grade matcha and powdered green teas, the Chl-a con- late and strictinin contents of tea（ Camellia sinensis L.） tents in industrial-grade matcha tended to be higher than cultivar ‘Benifuki’ in varous degree of maturity and leaf 10 those of powdered green tea. It is suggested that matcha order, Food Sci. Technol. Res., , 186-190 Maeda-Yamamoto, M., Nagai, H., Suzuki, Y., Ema, K., Kanda, E. is the powdered tea that has the greenest particles. In this and Mitsuda, H.（2005）, Changes in O-methylated catechin report, we compared chemical components only. A com- and chemical component contents of ‘Benifuuki’ green tea parison of physical properties, such as particle size, would （Camellia sinensis L.） beverage under various extraction 11 also be interesting to determine the characteristics of conditions, Food Sci. Technol. Res., , 248-253 Miwa, E., Takayanagi, H. and Nakagawa, M.（1978）, Distribu- matcha and other powdered teas. tion of the chemical constituents in different position of tea shoot, Tea Res. J.（in Japanese）, 47, 48-52 This research was supported by grants from the Saijo, R. （1999）, Japanese green tea – Characteristics and manufacture, “Global Advances in Tea Science”, Jane, J. K., Project of the Biooriented Technology Research Advance- Ed., Aravali Books International, New Delhi, pp. 761-766 ment Institution, NARO（the special scheme project on Saijo, R. and Osawa, K.（1981）, Regulation of products of cate- advanced research and development for next-generation chins and nitrogenous compounds by shade treatment on technology）. tea plants, Tea Res. J.（in Japanese）, 54, 40-46 Tachibana, H. and Shoyama, T.（1979）, Studies on the relation between color of tea leaves and its chlorophyll content, Tea REFERENCES Res. J.（in Japanese）, 49, 56-60 Chu, D.-C.（1997）, Green tea -its cultivation, processing of the Tokunaga, M.（2004）, Types of Japanese Green Tea, “New leaves for drinking materials, and kinds of green tea, Tastes in Green Tea, a novel flavor for familiar Drinks, “Chemistry and Applications of Green Tea”, Yamamoto, T., dishes, and desserts”, Kodansha International, Tokyo, pp. Juneja, L.R., Chu, D.-C. and Kim, M., Ed., CRC Press, New 17-19 York, pp. 1-11 Tsuji, M.（2001）, The relationship between chemical compo- Chu, D.-C. and Juneja L. R.（1997）, General chemical composi- nents and quality of tencha tea, Tea Res. J.（in Japanese）, tion of green tea and its infusion, “Chemistry and Applica- 90, 1-7 tions of Green Tea” Yamamoto, T., Juneja, L. R., Chu, D.-C. Wang, Y., Gao, L., Shan, Y., Liu, Y., Tian, Y. and Xia, T.（2012）, and Kim, M., Ed., CRC Press, New York, pp. 13-22 Influence of shade on flavonoid biosynthesis in teaCamel （ - Goto, T., Horie, H. and Mukai, T.（1993）, Analysis of major lia sinensis（L.） O. Kuntze）, Scientia Horticulturae, 141, amino acids in green tea by high-performance liquid chro- 7-16 matography coupled with OPA precolumn derivatization, Tea Res. J. 77 （in Japanese）, , 29-33 （Received Jan, 23, 2017 Accepted Jun, 20, 2017） Goto, T., Yoshida, Y., Amano, I. and Horie, H.（1996）, Chemical

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抹茶および粉末緑茶の化学成分

堀江秀樹*§ 江間かおり* 角川修**

和文抄録茶道用の抹茶以外に，「抹茶」と表示された粉末状の茶が食品産業や料理用に流通しており，本報ではこれらを業務用抹茶と記載する。さらには，抹茶とは表示されていない粉末緑茶も市販されている。しかしながら，これら粉末状の茶については品質に関する情報が乏しい。そこで，本研究においては，これらの粉末状の緑茶について化学成分を比較した。まず，抹茶原料であるてん茶について，品質の異なるものを 10 種類収集し化学分析した。分析結果に基づき，市販の抹茶や粉末緑茶のテアニン，クロロフィル a（Chl-a）の含量，エピガロカテキンガレート／エピガロカテキン（EGCG/EGC）の重量比について比較した。茶道用抹茶のテアニン含量および EGCG/EGC 比は，それぞれ乾物 100 g 当たり 1.8 g および 3.2 以上であった。業務用抹茶と粉末緑茶の大部分ではより低い値を示した。しかしながら，これらのパラメータだけでは加工用抹茶と粉末緑茶の判別はできなかった。茶道用抹茶の Chl-a 含量は 250 mg/100 g 乾物重以上であった。玉露粉以外の粉末緑茶試料では，茶道用や業務用の抹茶よりも Chl-a 含量が低かった。

キーワード：高速液体クロマトグラフィ，品質評価，てん茶，食品産業，料理

* 農研機構果樹茶業研究部門 ** 農研機構本部 § 連絡先農研機構金谷茶業研究拠点〒 428-8501 静岡県島田市金谷猪土居 2769 E-mail：[email protected]

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