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master's thesis
Usporedba antioksidativne aktivnosti suhih listića zelenog, žutog i crnog čaja i njihovih ekstrakata
2013. urn:nbn:hr:109:726534
Tadić, Maja
Josip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Department of Food Technologies
Sub-department of Fruits and Vegetables Technology

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Tadić, M. (2013). Usporedba antioksidativne aktivnosti suhih listića zelenog, žutog i crnog čaja i njihovih ekstrakata (Master's thesis). Osijek: Josip Juraj Strossmayer University of Osijek, FACULTY OF FOOD TECHNOLOGY. Retrieved from https://urn.nsk.hr/urn:nbn:hr:109:726534

Tadić, Maja. "Usporedba antioksidativne aktivnosti suhih listića zelenog, žutog i crnog čaja i njihovih ekstrakata." Master's thesis, Josip Juraj Strossmayer University of Osijek, FACULTY OF FOOD TECHNOLOGY, 2013. https://urn.nsk.hr/urn:nbn:hr:109:726534

Tadić, Maja. "Usporedba antioksidativne aktivnosti suhih listića zelenog, žutog i crnog čaja i njihovih ekstrakata." Master's thesis, Josip Juraj Strossmayer University of Osijek, FACULTY OF FOOD TECHNOLOGY, 2013. https://urn.nsk.hr/urn:nbn:hr:109:726534

Tadić, M. (2013). 'Usporedba antioksidativne aktivnosti suhih listića zelenog, žutog i crnog čaja i njihovih ekstrakata', Master's thesis, Josip Juraj Strossmayer University of Osijek, FACULTY OF FOOD TECHNOLOGY, accessed 30 September 2024, https://urn.nsk.hr/urn:nbn:hr:109:726534

Tadić M. Usporedba antioksidativne aktivnosti suhih listića zelenog, žutog i crnog čaja i njihovih ekstrakata [Master's thesis]. Osijek: Josip Juraj Strossmayer University of Osijek, FACULTY OF FOOD TECHNOLOGY; 2013 [cited 2024 September 30] Available at: https://urn.nsk.hr/urn:nbn:hr:109:726534

M. Tadić, "Usporedba antioksidativne aktivnosti suhih listića zelenog, žutog i crnog čaja i njihovih ekstrakata", Master's thesis, Josip Juraj Strossmayer University of Osijek, FACULTY OF FOOD TECHNOLOGY, Osijek, 2013. Available at: https://urn.nsk.hr/urn:nbn:hr:109:726534

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TitleUsporedba antioksidativne aktivnosti suhih listića zelenog, žutog i crnog čaja i njihovih ekstrakata
Title (english)Comparison of the Antioxidant Activity of Dry Leaves of Green, Yellow and Black Tea and Their Extracts
AuthorMaja Tadić
MentorMirela Kopjar (mentor)
Committee memberVlasta Piližota (predsjednik povjerenstva)
Committee memberMirela Kopjar (član povjerenstva)
Committee memberAnita Pichler (član povjerenstva)
Committee memberNela Nedić Tiban (član povjerenstva)
GranterJosip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
(Department of Food Technologies)
(Sub-department of Fruits and Vegetables Technology)
Osijek
Defense date and country2013-04-16, Croatia
Scientific / art field,
discipline and subdiscipline		BIOTECHNICAL SCIENCES
Food Technology
Food Chemistry
Abstract
U ovom radu ispitivan je utjecaj veličine čestica zelenog, žutog i crnog čaja (listići čaja i usitnjeni čaj) i ekstrakcijskog otapala na udio fenola, flavonoida, kondenziranih tanina, boju i antioksidativnu aktivnost. Najveći udio fenola (3,823, 4,226 i 6,829 g/kg za zeleni, crni i žuti čaj) određen je ekstraktima dobivenim zakiseljenim metanola usitnjenih listića čajeva. Primjenom metanola kao ekstrakcijskog otapala udio fenola se smanjivao redom žuti > zeleni > crni čaj, a primjenom zakiseljenog metanola udio fenola se smanjivao redom žuti > crni > zeleni čaj, bez obzira na veličinu čestica čajeva za ekstrakciju. Udio flavonoida i kondenziranih tanina pratio je tendenciju udjela fenola. Najveće vrijednosti antioksidativne aktivnosti su određene u ekstraktima dobivenim ekstrakcijom sa zakiseljenim metanolom usitnjenih uzoraka, bez obzira na metodu određivanja (DPPH i ABTS). U radu je korištena za određivanje antioksidativne aktivnosti i „QUENCHER“ metoda kod koje se direktno suhi uzorak hrane tretira slobodnim radikalima (DPPH i ABTS). Rezultati antioksidativne aktivnosti „QUENCHER“ metode su uspoređeni s rezultatima dobivenim nakon ekstrakcije sa zakiseljenim metanolom. Veće vrijednosti antioksidativne aktivnosti određene su u zelenom i žutom čaju primjenom „QUENCHER“ metode, za razliku od crnog čaja gdje je veća antioksidativna aktivnost određena u ekstraktu.
Abstract (english)
In this study influence of particle size of green, yellow and black tea (leaves and powdered leaves) and solvent on content of phenols, flavonoids and tannins, colour and antioxidant activity was investigated. Extracts obtained by extraction of powdered tea leaves with acidified methanol had the highest phenol content (3.823, 4.226 and 6.829 g/kg for green, black and yellow tea). In methanol extracts phenol content decreased in order yellow > green > black tea, and in acidified methanol extracts yellow > black > green tea, regardless of particle size. Flavonoid and tannins content followed the same tendency as phenol content. The highest antioxidant content had acidified methanol extracts of powdered tea leaves, regardless of used method (DPPH and ABTS). Also, in this study, for determination of antioxidant activity „QUENCHER“ method was used which is based on direct treatment of dry sample with free radicals (DPPH and ABTS). Results of antioxidant activity obtained with „QUENCHER“ method were compared with results of acidified methanol extracts. Green and yellow tea had higher antioxidant activity when „QUENCHER“ method was used in contrast to black tea where higher antioxidant activity was determined in extract.
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:109:726534
ProjectNumber: 113-1130473-0340
Title: Razvoj procesa proizvodnje visokokvalitetne hrane
Title: Development of processes for high quality foods
Leader: Vlasta Piližota
Jurisdiction: Croatia
Funder: MZOS
Funding stream: ZP
Study programmeTitle: Food Engineering
Study programme type: university
Study level: graduate
Academic / professional title: magistar/magistra inženjer/inženjerka prehrambenog inženjerstva (magistar/magistra inženjer/inženjerka prehrambenog inženjerstva)
Type of resourceText
File originBorn digital
Access conditionsAccess restricted to students and staff of home institution
Terms of useLicence In copyright icon
Created on2015-12-11 14:39:45