Doc:Tea

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{{Tea/Header}}
 
{{Tea/Header}}
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{| style="float:right"
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| __TOC__
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=={{Bilingual|お茶について|About Tea}}==
 
=={{Bilingual|お茶について|About Tea}}==
 
{{Twocolumn|
 
{{Twocolumn|
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more tannins and are used for black tea except for Darjeeling, which uses ''sinensis'', in India and Sri Lanka. Both species share the same number of　chromosomes and　easily crossbreed. Their mix grow in Indochina.
 
more tannins and are used for black tea except for Darjeeling, which uses ''sinensis'', in India and Sri Lanka. Both species share the same number of　chromosomes and　easily crossbreed. Their mix grow in Indochina.
 
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|
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お茶は[[Species:Camellia|''Camellia sinensis''  var.''sinensis'']]またはvar.''assamica''の葉から作ります。''sinensis''種の葉は小さくて丸く、樹高も4m以下で耐寒性です。日本や中国で栽培されます。''assamica''種は葉が大きくて先が尖り、樹高も10mを超えます。インドやスリランカで栽培されます。
+
お茶は[[Species:Camellia|''Camellia sinensis''  var.''sinensis'']]またはvar.''assamica''の葉から作ります。日本茶に使う sinensis 種の葉は小さくて丸く、樹高も4m以下で耐寒性です。日本や中国で栽培されます。アッサム紅茶で知られる assamica 種は葉が大きくて先が尖り、樹高も10mを超えます。インドやスリランカで栽培されます。
−
葉にはタンニンが多いため、ダージリン（これだけシネンシス種）以外の紅茶に用られます。両種は染色体数も同じで容易に交雑します。インドシナ地域の茶は雑種とされます。
+
その葉にはタンニンが多いため、ダージリン（紅茶の中でダージリンだけはシネンシス種）以外の紅茶に用られます。両種は染色体数も同じで容易に交雑します。インドシナ地域の茶は雑種とされています。
 
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}}
 
}}
  
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<center>
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{|
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{| style="text-align:center"
+
|
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! colspan="9" | Weak (弱い) <math>\Longleftarrow</math> Fermentation (醗酵度合) <math>\Longrightarrow</math> Strong (強い)
+
{| class=wikitable
 +
! fermentation ||
 
|-
 
|-
−
| White tea<br/>白茶 || &nbsp;&lt;&nbsp; || Green tea<br/>緑茶 || &nbsp;&lt;&nbsp; || Oolong tea<br/>烏龍茶 || &nbsp;&lt;&nbsp; || Black tea<br/>紅茶 || &nbsp;&lt;&nbsp; || Pu-erh tea<br/>普洱茶
+
| none
 +
| Green Tea | Steamed (Japan), Roasted (China)
 +
|-
 +
| partial
 +
| White, Oolong Tea | Taiwanese
 +
|-
 +
| full
 +
| Black Tea | Assam (India), Darjeeling (India), Uva (Sri Lanka)
 +
|-
 +
| post
 +
| Pu-erh Tea
 +
|}
 +
|
 +
{| class=wikitable
 +
! 発酵度合 ||
 +
|-
 +
| 無発酵
 +
| 緑茶 | 日本は蒸し、中国は釜炒り
 +
|-
 +
| 部分発酵
 +
| 白茶、烏龍茶 | 摇青の度合いにより、白茶、台湾茶、鉄観音など
 +
|-
 +
| 全発酵
 +
| 紅茶 | アッサム（インド）、ダージリン（インド）、スリランカ（ウバ）など
 +
|-
 +
| 後発酵
 +
| 普洱（プーアル）茶
 +
|}
 
|}
 
|}
−
</center>
+
 
  
 
=={{Bilingual|茶の分類|Classification of Tea}}==
 
=={{Bilingual|茶の分類|Classification of Tea}}==
 +
 +
  
 
==={{Bilingual|白茶|White Tea}}===
 
==={{Bilingual|白茶|White Tea}}===
 
{{Twocolumn|
 
{{Twocolumn|
−
White tea is covered with white hair, because of its special manufacturing process of "no crushing" (minimum treatment).  Only 2,000 tons per year is manufactured in Fujian Province, China. The general grade is: Silver Needle > White Peony > Gongmei and Shoumei. Silver Needle with White Hair is made from bulky buds only, White Peony is made from the bud and 1 or 2 leaves. For Silver Needle, young buds are harvested, withered and quickly basket fried (40-50 °C, 30 min for 250 g) to keep their fermentation minimal. For White Peony, frying temperature is 70-80 °C after withering.  
+
White tea is covered with white hair, because of its special manufacturing process of "no crushing" (minimum treatment).  Only 2,000 tons per year is manufactured in Fujian Province, China. The general grade is: Silver Needle > White Peony > Gongmei and Shoumei. Silver Needle with White Hair is made from bulky buds only, White Peony is made from the bud and 1 or 2 leaves. For Silver Needle, young buds are harvested, withered and quickly basket fried (40-50 ℃, 30 min for 250 g) to keep their fermentation minimal. For White Peony, frying temperature is 70-80 ℃ after withering.  
 
|
 
|
−
白茶の名は、揉捻（揉むこと）無しという特殊製法のため、茶葉が白い毛で覆われていることに由来します。福建省で年間2000トンしか生産されません。一般的な等級は白毫銀針＞白牡丹＞貢眉または寿眉です。白毫銀針には茶の若い蕾（つぼみ）のみを用い、白牡丹には蕾と若葉を１～２枚用います。白毫銀針は蕾を萎れさせてから籠でさっと炒るだけにし(40-50 °C, 250 gで30分程度)、醗酵を最低限に留めます。白牡丹は炒る温度が70-80 °Cになります。
+
白茶の名は、揉捻（揉むこと）無しという特殊製法のため、茶葉が白い毛で覆われていることに由来します。福建省で年間2000トンしか生産されません。一般的な等級は白毫銀針＞白牡丹＞貢眉または寿眉です。白毫銀針には茶の若い蕾（つぼみ）のみを用い、白牡丹には蕾と若葉を１～２枚用います。白毫銀針は蕾を萎れさせてから籠でさっと炒るだけにし(40-50 ℃, 250 gで30分程度)、醗酵を最低限に留めます。白牡丹は炒る温度が70-80 ℃になります。
 
}}
 
}}
  
 
==={{Bilingual|緑茶|Green Tea}}===
 
==={{Bilingual|緑茶|Green Tea}}===
 
{{Twocolumn|
 
{{Twocolumn|
−
It is non-fermented, i.e., produced by frying or steaming (fixation) the fresh leaves to inactivate polyphenol oxidases. Steaming is common in Japan whereas pan-frying is used in China.  Assan (''assamica'') type contains too much tannins and not suitable for green tea. Almost all green tea is consumed in Japan, Vietnam, China, and Indonesia only.
+
It is non-fermented, i.e., produced by frying or steaming (fixation) the fresh leaves to inactivate polyphenol oxidases. Steaming is common in Japan whereas pan-frying (firing) is used in China. Steaming completely stops the transformation of flavan-3-ols, i.e., catechins by polyphenol oxidase whereas pan-frying is less efficient and allows some transformation.
 +
 
 +
Assan (''assamica'') type contains too much tannins and not suitable for green tea. Almost all green tea is consumed in Japan, Vietnam, China, and Indonesia only.
 
|
 
|
−
新鮮な茶葉を炒るか蒸して作られる非醗酵茶。加熱によりポリフェノール酸化酵素の働きを止めます(固定といいます）。日本では茶葉を蒸しますが、中国では炒るようです。また、アッサム茶（紅茶）に使われる''assamica''種はタンニンが多く緑茶には向きません。緑茶はそのほとんどが日本、ベトナム、中国、インドネシアのみで消費されます。日本の煎茶は葉を蒸してから揉みますが、よしず棚などで覆って育てた新芽を蒸して乾燥させた茶を碾茶（てんちゃ）といいます。抹茶は碾茶を石臼で挽いたものです。
+
新鮮な茶葉を炒るか蒸して作られる非醗酵茶。加熱によりポリフェノール酸化酵素の働きを止めます(固定といいます）。日本では茶葉を蒸しますが、中国では炒ります。蒸すと酵素の働きを完全にストップさせますが、炒る場合はフラバン3-オール、つまりカテキンが少量、テアルビジン等に変化します。
 +
 
 +
また、アッサム茶（紅茶）に使われる''assamica''種はタンニンが多く緑茶には向きません。緑茶はそのほとんどが日本、ベトナム、中国、インドネシアのみで消費されます。日本の煎茶は葉を蒸してから揉みますが、よしず棚などで覆って育てた新芽を蒸して乾燥させた茶を碾茶（てんちゃ）といいます。抹茶は碾茶を石臼で挽いたものです。
 
}}
 
}}
  
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It is produced by partial fermentation before drying.  The process is called green leaf shaking (yaoqing), where mildly withered tea leaves are bruised at the edges by hand, and green leaf cooling (liangqing). Good oolong tea leaves have reddish edges with green centers.  It is mainly produced in Fujian, Guangdong (both China), and Taiwan.
 
It is produced by partial fermentation before drying.  The process is called green leaf shaking (yaoqing), where mildly withered tea leaves are bruised at the edges by hand, and green leaf cooling (liangqing). Good oolong tea leaves have reddish edges with green centers.  It is mainly produced in Fujian, Guangdong (both China), and Taiwan.
  
−
''Black oolong tea'' is usually roasted. ''Golden-colored oolong tea'', often manufactured in Taiwan, is lightly fermented oolong tea (closer to green tea).
+
''Black oolong tea'' is usually roasted. ''Golden-colored oolong tea'', produced in Taiwan, is lightly fermented oolong tea (closer to green tea).
 
|
 
|
 
乾燥前に部分的に醗酵させる、半醗酵茶です。茶葉を揺すって周辺部分を傷める摇青(yaoqing)作業と冷却する晾青(liangqing)を繰り返して作成します。良質のウーロン茶は周辺が赤っぽく、中央が緑色になります。ほとんどが中国の福建省、廣東省と台湾で生産されます。
 
乾燥前に部分的に醗酵させる、半醗酵茶です。茶葉を揺すって周辺部分を傷める摇青(yaoqing)作業と冷却する晾青(liangqing)を繰り返して作成します。良質のウーロン茶は周辺が赤っぽく、中央が緑色になります。ほとんどが中国の福建省、廣東省と台湾で生産されます。
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==={{Bilingual|紅茶|Black Tea}}===
 
==={{Bilingual|紅茶|Black Tea}}===
 
{{Twocolumn|
 
{{Twocolumn|
−
Unlike green tea, leaves are withered and rolled to crush leaf cells and release polyphenol oxidases.  Black tea in India, Sri Lanka, and Kenya is manufactured by a CTC (crushing, tearing, and curling) machine whereas in China an orthodox rotorvane is used.  After rolling, leaves are fermented for 0.5 - 3 hours at 25-35 °C with high humidity (>95%).  
+
Unlike green tea, leaves are withered and rolled to crush leaf cells and release polyphenol oxidases.  Black tea in India, Sri Lanka, and Kenya is manufactured by a CTC (crushing, tearing, and curling) machine whereas in China an orthodox rotorvane is used.  After rolling, leaves are fermented for 0.5 - 3 hours at 25-35 ℃ with high humidity (>95%).  
 
Leaves are fully oxidized and turn golden with floral aroma in this process.
 
Leaves are fully oxidized and turn golden with floral aroma in this process.
 
|
 
|
−
緑茶と違い、摘んだ茶葉が萎れてから撚って細胞を破壊し（ローリング）、ポリフェノール酸化酵素を働かせます。紅茶の製造にはインド、スリランカ、ケニヤではCTC装置を使いますが、中国では旧式のローラーを使います。ローリングの後、茶葉を0.5-3時間25-35°C高湿度(>95%)で醗酵させます。フラボノイド成分が完全に酸化すると茶葉は黄金色になり芳香を持ちます。
+
緑茶と違い、摘んだ茶葉が萎れてから撚って細胞を破壊し（ローリング）、ポリフェノール酸化酵素を働かせます。紅茶の製造にはインド、スリランカ、ケニヤではCTC装置を使いますが、中国では旧式のローラーを使います。ローリングの後、茶葉を0.5-3時間25-35 ℃ 高湿度(>95%)で醗酵させます。フラボノイド成分が完全に酸化すると茶葉は黄金色になり芳香を持ちます。
 
}}
 
}}
  
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==={{Bilingual|カテキン|Catechins}}===
 
==={{Bilingual|カテキン|Catechins}}===
−
{|
+
{{twocolumn|
−
|- valign="top"
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The major phenolics in green tea include catechins (flavan 3-ols). They are
 +
 
 +
* [[FL63AGNS0001|(-)-epigallocatechin-3-gallate]] (EGCG; 59% of total catechins),
 +
* [[FL63AGNS0003|(-)-epigallocatechin]] (EGC; 19%),
 +
* [[FL63ACNS0006|(-)-epicatechin-3-gallate]] (ECG; 13.6%), and
 +
* [[FL63ACNS0002|(-)-epicatechin]] (EC; 6.4%) <ref name="McKay">McKay DL, Blumberg JB (2002) "The role of tea in human health: An update" J Am Coll Nutr 21:1-13</ref>.
 +
Other smaller amounts come from
 +
* [[FL63ACNS0001|(+)-catechin]]
 +
* [[FL63AGNS0002|(+)-gallocatechin]], and
 +
* [[FL63AANS0002|(-)-epiafzelchin]].
 +
 
 +
Over 90 % of catechins are converted to theaflavins, thearubigins and others in black tea <ref name="USDA">USDA Database for the Flavonoid Contents of Selected Foods, Beltsville 2003</ref>. A cup of tea may contain 90 mg of EGCG <ref name="Wu">Wu CD, Wei GX (2002) "Tea as a functional food for oral health" Nutrition 18(5):443-444</ref>, but in human, EGCG is less bioavailable (i.e. little absorbed) than other green tea catechins. However, the bioavailability is different between species and genotypes <ref name="Kim">Kim S, Lee MJ, Hong J (2000) "Plasma and tissue levels of tea catechins in rats and mice during chronic consumption of green tea polyphenols" Nutr Cancer 37:41-48</ref><ref name="Loktionov">Loktionov A, Bingham S et al. (1998) "Apolipoprotein E genotype modulates the effect of black tea drinking on blood lipids and blood coagulation factors: A pilot study" Br J Nutr 79:133-139</ref>.
 
|
 
|
−
The major phenolics in green tea include catechins (flavan 3-ols). They are [[FL63AGNS0001|(-)-epigallocatechin-3-gallate]] (EGCG; 59% of total catechins), [[FL63AGNS0003|(-)-epigallocatechin]] (EGC; 19%), [[FL63ACNS0006|(-)-epicatechin-3-gallate]] (ECG; 13.6%), and [[FL63ACNS0002|(-)-epicatechin]] (EC; 6.4%) <ref name="McKay">McKay DL, Blumberg JB (2002) "The role of tea in human health: An update" J Am Coll Nutr 21:1-13</ref>. Catechins are converted to theaflavins and thearubigins in black tea <ref name="USDA">USDA Database for the Flavonoid Contents of Selected Foods, Beltsville 2003</ref>. A cup of tea may contain 90 mg of EGCG <ref name="Wu">Wu CD, Wei GX (2002) "Tea as a functional food for oral health" Nutrition 18(5):443-444</ref>, but in human, EGCG is less bioavailable (i.e. little absorbed) than other green tea catechins. However, the bioavailability is different between species and genotypes <ref name="Kim">Kim S, Lee MJ, Hong J (2000) "Plasma and tissue levels of tea catechins in rats and mice during chronic consumption of green tea polyphenols" Nutr Cancer 37:41-48</ref><ref name="Loktionov">Loktionov A, Bingham S et al. (1998) "Apolipoprotein E genotype modulates the effect of black tea drinking on blood lipids and blood coagulation factors: A pilot study" Br J Nutr 79:133-139</ref>.
+
緑茶中の主なフェノール化合物はカテキン(フラバン3-オール)で
−
|
+
* [[FL63AGNS0001|(-)-エピガロカテキン-3-ガレート]] (EGCG; 全カテキンの59%),
−
緑茶中の主なフェノール化合物はカテキン(フラバン3-オール)で、[[FL63AGNS0001|(-)-エピガロカテキン-3-ガレート]] (EGCG; 全カテキンの59%), [[FL63AGNS0003|(-)-エピガロカテキン]] (EGC; 19%), [[FL63ACNS0006|(-)-エピカテキン-3-ガレート]] (ECG; 13.6%)そして[[FL63ACNS0002|(-)-エピカテキン]] (EC; 6.4%) です。
+
* [[FL63AGNS0003|(-)-エピガロカテキン]] (EGC; 19%),
−
紅茶ではカテキンはテアフラビンとテアルビジンに変換されます。
+
* [[FL63ACNS0006|(-)-エピカテキン-3-ガレート]] (ECG; 13.6%)そして
−
コップ１杯のお茶にはおよそ90 mgのEGCGが含まれますがEGCGは他の茶カテキンに比べ、ヒト体内にあまり吸収されません。
+
* [[FL63ACNS0002|(-)-エピカテキン]] (EC; 6.4%) です。
 +
他に少量
 +
* [[FL63ACNS0001|(+)-catechin]]
 +
* [[FL63AGNS0002|(+)-gallocatechin]],
 +
* [[FL63AANS0002|(-)-epiafzelchin]]が含まれます。
 +
 
 +
紅茶では、90 % 以上のカテキンがテアフラビンやテアルビジン等に変換されます。
 +
コップ１杯のお茶にはおよそ90 mg のEGCGが含まれますがEGCGは他の茶カテキンに比べ、ヒト体内にあまり吸収されません。
 
生物学的な利用能力は生物種や遺伝型によって変化します。
 
生物学的な利用能力は生物種や遺伝型によって変化します。
 +
}}
  
−
|
 
 
{| class = "wikitable"
 
{| class = "wikitable"
 
! colspan="4" | Major Composition (%)<ref>Belitz DH, Grosch W (1997) "Quimica de los Alimentos" Zaragoza Acribia</ref>
 
! colspan="4" | Major Composition (%)<ref>Belitz DH, Grosch W (1997) "Quimica de los Alimentos" Zaragoza Acribia</ref>
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|-
 
|-
 
| Oxidized phenolics || 0 || 25 || 4.5
 
| Oxidized phenolics || 0 || 25 || 4.5
−
|}
 
 
|}
 
|}
  
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! Green and White Tea || Oolong Tea || Black Tea
 
! Green and White Tea || Oolong Tea || Black Tea
 
|-
 
|-
−
! Major Phonolics<br/> (フェノール化合物)
+
! {{Bilingual|フェノール化合物|Major Phenolics}}
 
|  
 
|  
 
{| class="wikitable" border="0"
 
{| class="wikitable" border="0"
 
|-
 
|-
−
| EGCG || [[FL63AGNS0001|(-)-エピガロカテキン-3-ガレート]]
+
| EGCG || [[FL63AGNS0001|{{Bilingual|(-)-エピガロカテキン-3-ガレート|(-)-epigallocatechin-3-gallate}}]]
 
|-
 
|-
−
| EGC  || [[FL63AGNS0003|(-)-エピガロカテキン]]
+
| EGC  || [[FL63AGNS0003|{{Bilingual|(-)-エピガロカテキン|(-)-epigallocatechin}}]]
 
|-
 
|-
−
| ECG  || [[FL63ACNS0006|(-)-エピカテキン-3-ガレート]]
+
| ECG  || [[FL63ACNS0006|{{Bilingual|(-)-エピカテキン-3-ガレート|(-)-epigallocatechin-3-gallate}}]]
 
|-
 
|-
−
| EC  || [[FL63ACNS0002|(-)-エピカテキン]]
+
| EC  || [[FL63ACNS0002|{{Bilingual|(-)-エピカテキン|(-)-epicatechin}}]]
 
|}
 
|}
−
| &rArr; oxidation &rArr;<br/>intermediate level <br/>(中間レベル)
+
| &rArr; oxidation &rArr;<br/>{{Bilingual|中間レベル|intermediate level}}
 
|  
 
|  
 
{|　class="wikitable" border="0"
 
{|　class="wikitable" border="0"
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==={{Bilingual|カフェイン|Caffeine}}===
 
==={{Bilingual|カフェイン|Caffeine}}===
−
{|
+
{{Twocolumn|
−
|- valign="top"
+
−
|
+
 
The caffeine content in different types of tea is: black tea > oolong tea > gree tea > fresh tea leaf <ref name="Lin">Lin Lin YS, Tsai YJ et al. (2003) "Factors affecting the levels of tea polyphenols and caffeine in te a leaves" J Agric Food Chem 51:1864-1873</ref>. More than 200 mg/day caffeine is not advisable and may produce nervousness, sleep disorders, vomits, headaches, epigastric pain, and tachycardia <ref name="Varnam">Varnam AH, Sutherland JP (1994) "Beverages: Technology, Chemistry and Microbiology" Chapman & Hall (London)</ref>.
 
The caffeine content in different types of tea is: black tea > oolong tea > gree tea > fresh tea leaf <ref name="Lin">Lin Lin YS, Tsai YJ et al. (2003) "Factors affecting the levels of tea polyphenols and caffeine in te a leaves" J Agric Food Chem 51:1864-1873</ref>. More than 200 mg/day caffeine is not advisable and may produce nervousness, sleep disorders, vomits, headaches, epigastric pain, and tachycardia <ref name="Varnam">Varnam AH, Sutherland JP (1994) "Beverages: Technology, Chemistry and Microbiology" Chapman & Hall (London)</ref>.
 
|
 
|
 
異なる茶に含まれるカフェインの量は 紅茶＞ウーロン茶＞緑茶＞新鮮な茶葉となります。
 
異なる茶に含まれるカフェインの量は 紅茶＞ウーロン茶＞緑茶＞新鮮な茶葉となります。
 
200 mg/日以上のカフェイン摂取は、イライラ、不眠、吐き気、頭痛、胃痛や頻脈を引き起こすので薦められません。
 
200 mg/日以上のカフェイン摂取は、イライラ、不眠、吐き気、頭痛、胃痛や頻脈を引き起こすので薦められません。
−
|
+
}}
 +
 
 
{| class = "wikitable"
 
{| class = "wikitable"
 
! colspan="4" | Caffeine Content in Beverages<ref name="Cabrera">Cabrera C, Artacho R, Gimenez R (2006) "Beneficial Effects of Green Tea-A Review" J Am Coll Nutr 25(2):79-99</ref>
 
! colspan="4" | Caffeine Content in Beverages<ref name="Cabrera">Cabrera C, Artacho R, Gimenez R (2006) "Beneficial Effects of Green Tea-A Review" J Am Coll Nutr 25(2):79-99</ref>
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|-
 
|-
 
| plain chocolate || 15 mg/20g || milk chocolate || 5 mg/20g
 
| plain chocolate || 15 mg/20g || milk chocolate || 5 mg/20g
−
|}
 
 
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|Tea synthesizes different saponins in leaves, seeds, and flower parts. In flower/bud, floratheasaponins are contained 1-2% of its dry weight<ref>Yoshikawa M, Morikawa T, Yamamoto K, Kato Y, Nagatomo A, Matsuda H (2005) ''J Nat Prod'' 68:1360-1365</ref>. Therefore, tea containing flowers bubbles like a soap.
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Tea synthesizes different saponins in leaves, seeds, and flower parts. In flower/bud, floratheasaponins are contained 1-2% of its dry weight<ref>Yoshikawa M, Morikawa T, Yamamoto K, Kato Y, Nagatomo A, Matsuda H (2005) ''J Nat Prod'' 68:1360-1365</ref>. Therefore, tea containing flowers bubbles like a soap.
 
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茶は葉部、種子、花蕾部でそれぞれ特有のサポニンを作ります。特に花にはfloratheasaponinが多く、乾燥重量の1-2%を占め、茶花の入った茶は石鹸のように泡立ちます。
 
茶は葉部、種子、花蕾部でそれぞれ特有のサポニンを作ります。特に花にはfloratheasaponinが多く、乾燥重量の1-2%を占め、茶花の入った茶は石鹸のように泡立ちます。
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Latest revision as of 17:52, 20 January 2013

Tea Top Exotic teas Production/Consumption Health

Contents

[edit] About Tea

Tea is made from leaves of Camellia sinensis var.sinensis or var.assamica. The former has small round leaves and the tree height is lower than 4m. It is cold resistant and is cultivated in Japan and China. The assamica has large pointed leaves and its tree height is over 10m. Its leaves contain more tannins and are used for black tea except for Darjeeling, which uses sinensis, in India and Sri Lanka. Both species share the same number of　chromosomes and　easily crossbreed. Their mix grow in Indochina.

Different tastes and flavors mainly come from manufactural differences. The degree of fermentation is as follows.

fermentation
none Steamed (Japan), Roasted (China)
partial Taiwanese
full Assam (India), Darjeeling (India), Uva (Sri Lanka)
post Pu-erh Tea
発酵度合
無発酵 日本は蒸し、中国は釜炒り
部分発酵 摇青の度合いにより、白茶、台湾茶、鉄観音など
全発酵 アッサム（インド）、ダージリン（インド）、スリランカ（ウバ）など
後発酵 普洱（プーアル）茶


[edit] Classification of Tea

[edit] White Tea

White tea is covered with white hair, because of its special manufacturing process of "no crushing" (minimum treatment). Only 2,000 tons per year is manufactured in Fujian Province, China. The general grade is: Silver Needle > White Peony > Gongmei and Shoumei. Silver Needle with White Hair is made from bulky buds only, White Peony is made from the bud and 1 or 2 leaves. For Silver Needle, young buds are harvested, withered and quickly basket fried (40-50 ℃, 30 min for 250 g) to keep their fermentation minimal. For White Peony, frying temperature is 70-80 ℃ after withering.

[edit] Green Tea

It is non-fermented, i.e., produced by frying or steaming (fixation) the fresh leaves to inactivate polyphenol oxidases. Steaming is common in Japan whereas pan-frying (firing) is used in China. Steaming completely stops the transformation of flavan-3-ols, i.e., catechins by polyphenol oxidase whereas pan-frying is less efficient and allows some transformation. Assan (assamica) type contains too much tannins and not suitable for green tea. Almost all green tea is consumed in Japan, Vietnam, China, and Indonesia only.

[edit] Blue or Oolong Tea

It is produced by partial fermentation before drying. The process is called green leaf shaking (yaoqing), where mildly withered tea leaves are bruised at the edges by hand, and green leaf cooling (liangqing). Good oolong tea leaves have reddish edges with green centers. It is mainly produced in Fujian, Guangdong (both China), and Taiwan. Black oolong tea is usually roasted. Golden-colored oolong tea, produced in Taiwan, is lightly fermented oolong tea (closer to green tea).

[edit] Black Tea

Unlike green tea, leaves are withered and rolled to crush leaf cells and release polyphenol oxidases. Black tea in India, Sri Lanka, and Kenya is manufactured by a CTC (crushing, tearing, and curling) machine whereas in China an orthodox rotorvane is used. After rolling, leaves are fermented for 0.5 - 3 hours at 25-35 ℃ with high humidity (>95%). Leaves are fully oxidized and turn golden with floral aroma in this process.

[edit] Pu-erh Tea

Raw pu-erh tea is produced by pressing tea leaves and fermenting for years, sometimes for decades. Ripened pu-erh tea, which is more popular, is inoculated with black Aspergillus and fermented under an optimal condition for several months. From Yunnan Pu-erh tea, Aspergillus niger, A. gloucu, and species of Penicillium, Rhizopus, Saccharomyces, and Bacterium are found. A. niger is the most predominant, followed by Saccharomyces spp. [1] Ripened pu-erh tea contains less catechins than raw pu-erh tea, but more gallic acid as the degradation products of catechins (and others). Antioxidant activity is significantly higher for raw pu-erh tea.[2]

  1. ↑ Jeng KC, Chen CS, Fang YP, Hou RCW, Chen YS (2007) "Effect of microbial fermentation on content of statin, GABA, and polyphenols in pu-erh tea" J. Agric. Food Chem. 55:8787-8792
  2. ↑ Ku KM, Kim J, Park HJ, Liu KH, Lee CH (2010) "Application of Metabolomics in the Analysis of Manufacturing Type of Pu-erh Tea and Composition Changes with Different Postfermentation Year" J. Agric. Food Chem. 58:345-352

[edit] Tea Composition

[edit] Catechins

The major phenolics in green tea include catechins (flavan 3-ols). They are

Other smaller amounts come from Over 90 % of catechins are converted to theaflavins, thearubigins and others in black tea [2]. A cup of tea may contain 90 mg of EGCG [3], but in human, EGCG is less bioavailable (i.e. little absorbed) than other green tea catechins. However, the bioavailability is different between species and genotypes [4][5].

Major Composition (%)[6]
Compound Green tea Black tea Black tea
Infusion (3min)
Proteins 15 15 trace
Amino acids 4 4 3.5
Fiber 26 26 0
Others, carbohydrates 7 7 4
Lipids 7 7 trace
Pigments 2 2 trace
Minerals 5 5 4.5
Phenolic compounds 30 5 4.5
Oxidized phenolics 0 25 4.5
Tea type Green and White Tea Oolong Tea Black Tea
Major Phenolics
EGCG (-)-epigallocatechin-3-gallate
EGC (-)-epigallocatechin
ECG (-)-epigallocatechin-3-gallate
EC (-)-epicatechin
⇒ oxidation ⇒
intermediate level
theaflavin テアフラビン
thearubigin テアルビジン

After drinking tea, catechins are absorbed in the small intestine, and the plasma level of catechins reach their peaks (between 1-10 µmol/L) in 2 - 4 h [7]. Only less than 2 % of ingested catechins were found in the plasma, and gallated catechins are less bioavailable than non-gallated forms [8]. After 24 h, plasma levels of EGCG and EGC return to baseline, but that of ECG remains elevated in methylated forms[9].

  1. ↑ McKay DL, Blumberg JB (2002) "The role of tea in human health: An update" J Am Coll Nutr 21:1-13
  2. ↑ USDA Database for the Flavonoid Contents of Selected Foods, Beltsville 2003
  3. ↑ Wu CD, Wei GX (2002) "Tea as a functional food for oral health" Nutrition 18(5):443-444
  4. ↑ Kim S, Lee MJ, Hong J (2000) "Plasma and tissue levels of tea catechins in rats and mice during chronic consumption of green tea polyphenols" Nutr Cancer 37:41-48
  5. ↑ Loktionov A, Bingham S et al. (1998) "Apolipoprotein E genotype modulates the effect of black tea drinking on blood lipids and blood coagulation factors: A pilot study" Br J Nutr 79:133-139
  6. ↑ Belitz DH, Grosch W (1997) "Quimica de los Alimentos" Zaragoza Acribia
  7. ↑ Yang CS, Chen L et al. (1998) "Blood and urine levels of tea catechins after ingestion of different amounts of green tea by human volunteers" Cancer Epidemiol Biomarkers Prev 7:351-354
  8. ↑ Warden BA, Smith LS, Beecher GR, Balentine DA, Clevidence BA (2001) "Catechins are bioavailable in men and women drinking black tea throughout the day" J Nutr 131:1731-1737
  9. ↑ Higdon JV, Frei B (2003) "Tea catechins and polyphenols: health effects, metabolism, and antioxidant functions" Crit Rev Food Sci Nutr 43:89-143

[edit] Caffeine

The caffeine content in different types of tea is: black tea > oolong tea > gree tea > fresh tea leaf [1]. More than 200 mg/day caffeine is not advisable and may produce nervousness, sleep disorders, vomits, headaches, epigastric pain, and tachycardia [2].

Caffeine Content in Beverages[3]
Product content (mg /150mL) Product content (mg /150mL)
espresso coffee 108-180 normal coffee 80-115
instant coffee 65 black tea (3min brew) 40-70
oolong tea 18-33 iced tea 29
green tea (3min brew) 15-25 cola soft drink 15-19
hot chocolate 4 cocoa milk shake 3
decaffeinated coffee 1-3 decaffeinated tea 0.6-3
plain chocolate 15 mg/20g milk chocolate 5 mg/20g
  1. ↑ Lin Lin YS, Tsai YJ et al. (2003) "Factors affecting the levels of tea polyphenols and caffeine in te a leaves" J Agric Food Chem 51:1864-1873
  2. ↑ Varnam AH, Sutherland JP (1994) "Beverages: Technology, Chemistry and Microbiology" Chapman & Hall (London)
  3. ↑ Cabrera C, Artacho R, Gimenez R (2006) "Beneficial Effects of Green Tea-A Review" J Am Coll Nutr 25(2):79-99

[edit] Saponins

Tea synthesizes different saponins in leaves, seeds, and flower parts. In flower/bud, floratheasaponins are contained 1-2% of its dry weight[1]. Therefore, tea containing flowers bubbles like a soap.

Cf. Category:Floratheasaponin

Parts Major phytochemical contents
Leaf catechins > caffeine >> saponins, flavonoids
Flower/bud/pistil floratheasaponins > flavonols > caffeine >> catechins
Seed theasaponins, assamsaponins >> flavonoids
References
  1. ↑ Yoshikawa M, Morikawa T, Yamamoto K, Kato Y, Nagatomo A, Matsuda H (2005) J Nat Prod 68:1360-1365
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