Efficiency of the extraction of catechins from green tea

Yoshida, Yasuhiko; Kiso, Masaaki; Goto, Tetsuhisa

doi:10.1016/s0308-8146(99)00148-x

Cited by 86 publications

(59 citation statements)

References 11 publications

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“…These results correspond to the previous studies that found that catechins are more stable at lower pH levels. Yoshida et al reported that the extraction efficiency was increased as the solvent pH decreased, 27) and Zuo et al also increased the extraction efficiency by adding 0.15% HCl to methanol solvents. 24) Tuominen and Sundman also reported the hydrolysable tannins were unstable in basic conditions because of polyphenol oxidation.…”

Section: Resultsmentioning

confidence: 99%

Analysis of Green Tea Compounds and Their Stability in Dentifrices of Different pH Levels

Jang

Park

Ahn

et al. 2014

CHEMICAL & PHARMACEUTICAL BULLETIN

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In this study, green tea compounds (flavonoids, alkaloids, and phenolic acids) were analyzed in green tea-containing dentifrices, and their stability at different pH levels was evaluated. The compounds were separated under 0.01% phosphoric acid-acetonitrile gradient conditions and detected by photodiode array detector at 210, 280, 300, 335 nm. Column temperature was set at 20°C based on the results of screening various temperatures. Each compound showed good linearity at optimized wavelength as well as showing good precision and accuracy in dentifrices. Using this method, the stability of compounds was investigated in pH 4, 7, 8, and 10 solutions for 96 h, and in pH 7 and pH 10 solutions for 6 months. The green tea compounds were more stable at low pH levels; purine alkaloids were more stable than flavonoids. In particular, gallocatechin (GC), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin gallate (GCG), and myricetin almost disappeared in pH 10 solutions after 96 h. In dentifrices, the compounds were gradually decreased until 6 months in both pH types, while gallic acid was increased because of production of galloyl ester of other green tea compounds. Therefore, it is beneficial to adjust to as low a pH as possible when produce green teacontaining dentifrices.

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Section: Resultsmentioning

confidence: 99%

Analysis of Green Tea Compounds and Their Stability in Dentifrices of Different pH Levels

Jang

Park

Ahn

et al. 2014

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…Podjęte badania miały także na celu sprawdzenie na ile opisywane w literaturze alternatywne metody ekstrakcji wykorzystywane przy oznaczaniu zawartości innych bioaktywnych związków w herbatach zielonych i czarnych, m.in. katechin [2,11,13,20,23], mogą mieć wpływ na wyniki oznaczania rozpuszczalnych szczawianów.…”

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Effect of Extraction Conditions on the Soluble Oxalate Content in Water Infusions of Green and Herbal Teas

Sperkowska¹,

Bazylak²

2010

ZNTJ

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 WPŁYW WARUNKÓW EKSTRAKCJI NA ZAWARTOŚĆ ROZPUSZCZALNYCH SZCZAWIANÓW W WODNYCH NAPARACH HERBAT ZIELONYCH I HERBATEK ZIOŁOWYCHS t r e s z c z e n i e Celem pracy było porównanie zawartości rozpuszczalnych szczawianów (RSZ) w wodnych naparach herbat zielonych i herbatek ziołowych uzyskiwanych przy zastosowaniu czterech sposobów ekstrakcji, tj. tradycyjnej metody ekstrakcji przy użyciu wrzącej wody o temp. 100 ºC, ekstrakcji wspomaganej promieniowaniem mikrofalowym w temp. 80 ºC (EWPM), ekstrakcji wspomaganej ultradźwiękami w temp. 40 ºC (EWU-40) i w temp. 60 ºC.Oznaczona metodą manganianometryczną średnia zawartość RSZ w badanych naparach była najwięk-sza po zastosowaniu metody EWPM i wynosiła od 7,73 do 14,89 mg/g s.m. w herbatach zielonych oraz od 3,53 do 18,11 mg/g s.m. w herbatkach ziołowych. Natomiast najmniejsze wartości otrzymano po zastosowaniu metody EWU-40, tzn. od 5,06 do 10,88 mg/g s.m. w herbatach zielonych oraz od 1,5 do 11,03 mg/g s.m. w herbatkach ziołowych. W przypadku herbatek ziołowych, pobranych do badań wyłącznie w saszetkach do parzenia ekspresowego, stwierdzono istotną zależność pomiędzy ilością oznaczonych RSZ a rodzajem części anatomicznych wyjściowego surowca roślinnego. Podobnie, jak w przypadku herbat zielonych, największą średnią zawartością RSZ charakteryzowały się napary uzyskane metodą EWPM z herbatek ziołowych z całych liści, np. mięty -18,11 mg/g s.m., szałwi -12,23 mg/g s.m. oraz pokrzywy -11,76 mg/g s.m. Z owoców (nasion) kopru włoskiego uzyskano RSZ na poziomie 3,53 mg/g s.m. produktu, a z kwiatostanu lipy 4,01 mg/g s.m. Wyjątek w tej grupie naparów stanowił kwiatostan rumianku, w którym oznaczono 16,05 mg/g s.m. produktu.Uzyskane wyniki mogą zostać wykorzystane do standaryzacji metod analitycznych stosowanych podczas oznaczania RSZ w naparach herbat zielonych i herbatek ziołowych w celu identyfikacji kraju i regionu ich pochodzenia, rozpoznawania okresu zbiorów i sposobu produkcji, ujawniania domieszek i zafał-szowań oraz weryfikacji przydatności do spożycia i potwierdzania jakości zdrowotnej takich produktów.Słowa kluczowe: kwas szczawiowy, szczawiany, herbata zielona, herbatka ziołowa, ekstrakcja, promieniowanie mikrofalowe, ultradźwięki Mgr inż. B. Sperkowska, dr hab. G. Bazylak, prof. UMK, Katedra Bromatologii, Wydz. Farmaceutyczny, Collegium Medicum im.

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“…This condition was maintained for 2 min, followed by an increase of solvent B to 80% over 5 min. The final condition was held for an additional 5 min (Terada et al, 1987;Yoshida et al, 1999).…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, we attempted to improve the taste and aroma of green tea by sub-critical water extraction (SWE), which has rarely been applied to food processing and does not require additives. Conventionally, green tea extracts containing high catechin levels have been obtained by hydrothermal extraction (pressurized extraction), enzyme reaction extraction (Anan et al, 1981;Yoshida et al, 1999), or solvent extraction using alcohol, methanol, etc. However, these techniques have a number of disadvantages, such as requiring a prolonged extraction time at high temperatures to ensure a high extraction rate, as well as the increased risk and handling difficulty associated with using enzymes or organic solvents.…”

Section: Introductionmentioning

confidence: 99%

Improvement of the Bitterness and Astringency of Green Tea by Sub-Critical Water Extraction

Miyashita

Etoh

2013

FSTR

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Green tea is known for its high content of functional catechins and is commonly consumed for its health-promoting effects. However, green tea catechins are highly bitter and astringent, and thus the development of products that can be consumed regularly is necessary for their efficient, routine intake. The aim of this study was to use sub-critical water extraction (SWE) to produce a green tea extract both less bitter and less astringent than typical green tea. Results from chemical evaluation using a taste sensor analyzer indicated that SWE reduced bitterness, astringency and unpleasant taste while it retained the original fragrance in the green tea extract. Furthermore, the SWE-produced extract had higher amounts of arginine and water-soluble pectin, which are thought to mask the bitterness and astringency of green tea.

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Efficiency of the extraction of catechins from green tea

Cited by 86 publications

References 11 publications

Analysis of Green Tea Compounds and Their Stability in Dentifrices of Different pH Levels

Analysis of Green Tea Compounds and Their Stability in Dentifrices of Different pH Levels

Effect of Extraction Conditions on the Soluble Oxalate Content in Water Infusions of Green and Herbal Teas

Improvement of the Bitterness and Astringency of Green Tea by Sub-Critical Water Extraction

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