-
Extraction of active ingredients from green tea (Camellia sinensis): extraction efficiency of major catechins and caffeinePerva, Amra ...The effect of different extraction set-ups that influence the extraction efficiency of catechins and caffeine from green tea leaves (variety Fanning Belas, China) were studied using different aqueous ... and pure solvents (acetone,ethanol, methanol, acetonitrile, water), different temperatures (60, 80, 95 and 100 °C) and times (5-240 min). Raw extracts were analysed for contents of major catechins (EC, EGC, ECG, EGCG), caffeine, proanthocyanidins and flavonols (myricetin, caempherol, quercetin). Starting material was found to contain 191 g major catechins/kg material, 36 g caffeinežkg material and 5.2 g flavonols/kg material on a dry mass basis. The content of major catechins in green tea extracts varied from approximately 280-580 g/kg dry extract, with extraction efficiencies of major catechins varying from 61% to almost 100%. Content of caffeine in extract was in the range of 75 g/kg, where its extraction efficiency varied from 62% to 76%. Average extraction yield was 30% with exceptions when using pure acetone and acetonitrile, where extraction yield was about 3%. Contents of flavonols and proanthocyanidins were in the ranges 6-20 and 12-19 g/kg, respectively. Different extraction procedures with water were also investigated and optimal conditions determined: maximum achieved extraction efficiency of catechins with water wasobtained at 80 °C after 20 min (97%) and at 95 °C after 10 min of extraction (90%). Degradation of catechins was observed at higher extraction temperatures and with prolonged extraction times. Using a lower ratio of solvent to material, extraction efficiencies were increased by applying a multi-step extraction procedure. Optimal extraction procedure was then performed using decaffeinated green tea leaves, which were obtained by high-pressure extraction with CO2, when 98% of caffeine was selectively isolated without significant impact on valuable catechins.Vir: Food chemistry. - ISSN 0308-8146 (Vol. 96, iss. 4, 2006, str. 597-605)Vrsta gradiva - članek, sestavni delLeto - 2006Jezik - angleškiCOBISS.SI-ID - 10130198
Avtor
Perva, Amra |
Škerget, Mojca |
Knez, Željko |
Weinreich, Bernd |
Otto, Frank |
Grüner, Sabine
Teme
kemijska procesna tehnika |
ekstrakcija |
zeleni čaj |
kateini |
kofein |
ekstrakt dekafeiniranega zelenega čaja |
ekastrakt surovega zelenega čaja |
chemical processing |
extraction |
green tea |
catechins |
caffein |
decaffeinated green tea extract |
raw green tea extract
Vnos na polico
Trajna povezava
- URL:
Faktor vpliva
Dostop do baze podatkov JCR je dovoljen samo uporabnikom iz Slovenije. Vaš trenutni IP-naslov ni na seznamu dovoljenih za dostop, zato je potrebna avtentikacija z ustreznim računom AAI.
Leto | Faktor vpliva | Izdaja | Kategorija | Razvrstitev | ||||
---|---|---|---|---|---|---|---|---|
JCR | SNIP | JCR | SNIP | JCR | SNIP | JCR | SNIP |
Baze podatkov, v katerih je revija indeksirana
Ime baze podatkov | Področje | Leto |
---|
Povezave do osebnih bibliografij avtorjev | Povezave do podatkov o raziskovalcih v sistemu SICRIS |
---|---|
Perva, Amra | 21690 |
Škerget, Mojca | 11865 |
Knez, Željko | 02619 |
Weinreich, Bernd | |
Otto, Frank | |
Grüner, Sabine |
Izberite prevzemno mesto:
Prevzem gradiva po pošti
Obvestilo
Gesla v Splošnem geslovniku COBISS
Izbira mesta prevzema
Mesto prevzema | Status gradiva | Rezervacija |
---|
Prosimo, počakajte trenutek.