Fenolni sastav i antioksidacijski kapacitet različito pripremljenih ekstrakata bijelog i zelenog čaja

Kovač, Maja

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master's thesis

Fenolni sastav i antioksidacijski kapacitet različito pripremljenih ekstrakata bijelog i zelenog čaja

Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology, 2007. urn:nbn:hr:159:124226

Kovač, Maja

University of Zagreb
Faculty of Food Technology and Biotechnology
Department of Food Engineering
Laboratory for Chemistry and Technology of Carbohydrates and Confectionery Products

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APA 6th Edition

Kovač, M. (2007). Fenolni sastav i antioksidacijski kapacitet različito pripremljenih ekstrakata bijelog i zelenog čaja (Master's thesis). Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology. Retrieved from https://urn.nsk.hr/urn:nbn:hr:159:124226

MLA 8th Edition

Kovač, Maja. "Fenolni sastav i antioksidacijski kapacitet različito pripremljenih ekstrakata bijelog i zelenog čaja." Master's thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, 2007. https://urn.nsk.hr/urn:nbn:hr:159:124226

Chicago 17th Edition

Harvard

Kovač, M. (2007). 'Fenolni sastav i antioksidacijski kapacitet različito pripremljenih ekstrakata bijelog i zelenog čaja', Master's thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, accessed 29 December 2024, https://urn.nsk.hr/urn:nbn:hr:159:124226

Vancouver

Kovač M. Fenolni sastav i antioksidacijski kapacitet različito pripremljenih ekstrakata bijelog i zelenog čaja [Master's thesis]. Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology; 2007 [cited 2024 December 29] Available at: https://urn.nsk.hr/urn:nbn:hr:159:124226

IEEE

M. Kovač, "Fenolni sastav i antioksidacijski kapacitet različito pripremljenih ekstrakata bijelog i zelenog čaja", Master's thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, Zagreb, 2007. Available at: https://urn.nsk.hr/urn:nbn:hr:159:124226

Cite this item: https://urn.nsk.hr/urn:nbn:hr:159:124226

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Title	Fenolni sastav i antioksidacijski kapacitet različito pripremljenih ekstrakata bijelog i zelenog čaja
Title (english)	The phenolic composition and antioxidative capacity of white and green tea prepared at different extraction conditions
Author	Maja Kovač
Mentor	Draženka Komes (mentor)
Granter	University of Zagreb Faculty of Food Technology and Biotechnology (Department of Food Engineering) (Laboratory for Chemistry and Technology of Carbohydrates and Confectionery Products) Zagreb
Defense date and country	2007-12-18, Croatia
Scientific / art field, discipline and subdiscipline	BIOTECHNICAL SCIENCES Food Technology
Abstract	U ovom radu ispitana je učinkovitost različitih otapala (voda, smjesa vode i limuna, 10%-tni, 40%-tni i 70%-tni etanol) na ekstrakciju ukupnih polifenola i flavonoida iz listova bijelog i zelenog čaja ("rinfuzni" oblik i filter vrećica) nakon različitog trajanja ekstrakcije (5, 15 i 30 minuta) te antioksidacijski kapacitet dobivenih ekstrakata. Zeleni čaj je bogatiji izvor fenolnih spojeva u usporedbi s bijelim čajem, premda učinkovitost ekstrakcije tih spojeva uvelike ovisi o duljini trajanja ekstrakcije i korištenom otapalu. Na ekstrakciju katehina iz zelenog čaja značajno utječe oblik čaja (filter vrećica ili "rinfuza"), dok se taj učinak nije pokazao statistički značajnim kod bijelog čaja. Ekstrakcija fenola vodom iz listova bijelog čaja može se ubrzati dodatkom limunovog soka. Meñu ispitivanim otapalima, 40%-tni etanol je najučinkovitije otapalo tijekom produljene ekstrakcije (30 min) katehina, posebice epigalokatehin galata.
Abstract (english)	In this study efficiency of different solvents (water, mixture of water and lemon juice, 10, 40 and 70% ethanol) in extraction of total polyphenols and flavonoids from leaves of white and green tea (bagged and loose form) after different extraction time (5, 15, 30 min) and antioxidative capacity of obtained extracts were investigated. Green tea is richer source of phenolic compounds compared to white tea, but extraction efficiency of these compounds strongly depend on time of extraction and solvents used. The extraction efficiency of catechins from green tea was significantly affected by form (bagged or loose) of tea used, whereas this effect was not shown to be statistically significant for white tea. The extraction of phenolic compounds from white tea leaves by water could be accelerated by adding of lemon juice. 40% ethanol is the most effective among solvents tested in prolonged extraction (30 min) of catechins, especially in extraction of epigallocatechin gallate (EGCG). The antioxidative capacity of the investigated tea extracts correlates with their phenolic content.
Keywords
Keywords (english)
Language	croatian
URN:NBN	urn:nbn:hr:159:124226
Study programme	Title: Food Technology; specializations in: Food Engineering Course: Food Engineering Study programme type: university Study level: graduate Academic / professional title: diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo (diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo)
Type of resource	Text
File origin	Born digital
Access conditions	Access restricted to students and staff of home institution
Terms of use
Repository	Repository of the Faculty of Food Technology and Biotechnology
Created on	2017-09-05 11:40:46