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master's thesis
Ekstrakcija polifenola žutog čaja primjenom ultrazvuka visoke snage
Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology, 2009. urn:nbn:hr:159:985486
Donjerković, Petra
University of Zagreb
Faculty of Food Technology and Biotechnology
Department of Food Engineering
Laboratory for Chemistry and Technology of Carbohydrates and Confectionery Products

Cite this document

Donjerković, P. (2009). Ekstrakcija polifenola žutog čaja primjenom ultrazvuka visoke snage (Master's thesis). Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology. Retrieved from https://urn.nsk.hr/urn:nbn:hr:159:985486

Donjerković, Petra. "Ekstrakcija polifenola žutog čaja primjenom ultrazvuka visoke snage." Master's thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, 2009. https://urn.nsk.hr/urn:nbn:hr:159:985486

Donjerković, Petra. "Ekstrakcija polifenola žutog čaja primjenom ultrazvuka visoke snage." Master's thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, 2009. https://urn.nsk.hr/urn:nbn:hr:159:985486

Donjerković, P. (2009). 'Ekstrakcija polifenola žutog čaja primjenom ultrazvuka visoke snage', Master's thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, accessed 17 November 2024, https://urn.nsk.hr/urn:nbn:hr:159:985486

Donjerković P. Ekstrakcija polifenola žutog čaja primjenom ultrazvuka visoke snage [Master's thesis]. Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology; 2009 [cited 2024 November 17] Available at: https://urn.nsk.hr/urn:nbn:hr:159:985486

P. Donjerković, "Ekstrakcija polifenola žutog čaja primjenom ultrazvuka visoke snage", Master's thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, Zagreb, 2009. Available at: https://urn.nsk.hr/urn:nbn:hr:159:985486

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Metadata
TitleEkstrakcija polifenola žutog čaja primjenom ultrazvuka visoke snage
Title (english)Ultrasound-assisted extraction of polyphenols from yellow tea
AuthorPetra Donjerković
MentorDraženka Komes (mentor)
GranterUniversity 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 country2009-12-18, Croatia
Scientific / art field,
discipline and subdiscipline		BIOTECHNICAL SCIENCES
Food Technology
Abstract
Cilj istraživanja bio je odrediti udio ukupnih fenola i antioksidacijski kapacitet u čaju. Žuti čaj u rinfuzi ekstrahiran je vodom i 75 %-tnim etanolom uz primjenu ultrazvuka amplitude 25 %, 50 %, 75 % i 100 % u trajanju od 3, 5, 10, 15 i 30 minuta. Također su pripremljeni vodeni i 75 %-tni etanolni ekstrakti, kombinacijom navedenih amplituda ultrazvuka i ponovljenih ekstrakcija istog uzorka tijekom 3 minute. Antioksidacijski kapacitet određen je primjenom tri metode: reakcija s 1, 1- difenil- 2- pikrilhidrazil (DPPH), reakcija s 2, 2'- azinobis(3- etilbenzotiazolin- 6- sulfonska kiselinom) (ABTS), te reakcija sa željezo(III)- tripiridiltriazinom (FRAP). Najveći udio fenola određen je u čaju ekstrahiranom vodom uz primjenu ultrazvuka 50 %-tne amplitude tijekom 30 minuta, a najmanji u čaju ekstrahiranom vodom uz primjenu ultrazvuka 100 %-tne amplitude tijekom 3 minute (3. ekstrakcija). Najveći antioksidacijski kapacitet izmjeren je u čaju ekstrahiranom 75 %-tnim etanolom uz primjenu 50 %-tne amplitude tijekom 30 minuta, a najmanji u trećem vodenom ekstraktu pripremljenim primjenom ultrazvuka 75 %-tne amplitude.
Abstract (english)
The purpose of this research was to determine the total polyphenol content and antioxidant capacity in tea. The yellow tea in loose leaf form was extracted with water and 75% ethanol using ultrasound amplitudes of 25 %, 50 %, 75% and 100 % lasting 3, 5, 10, 15 and 30 minutes. In addition, water and 75 % ethanol extracts were prepared using the aforementioned ultrasound amplitudes and multiple extractions during 3 minutes.The antioxidant capacity was determened using three methods: DPPH (reduction of (1, 1-diphenyl-2- picrylhydrazyl), ABTS (reaction of 2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) and FRAP (reaction with iron(III)tripyridyiltriazine).The highest polyphenol content is determined in tea extracted with water using 50% amplitude ultrasound during 30 minutes and the lowest in water extracted tea using 100% amplitude ultrasound during 3 minutes (third extraction). The highest antioxidant capacity was measured in tea extracted with 75% ethanol using 50% amplitude during 30 minutes and the lowest in the third water extract prepared using 75% amplitude ultrasound.
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:159:985486
Study programmeTitle: 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 resourceText
File originBorn digital
Access conditionsAccess restricted to students and staff of home institution
Terms of useLicence In copyright icon
RepositoryRepository of the Faculty of Food Technology and Biotechnology
Created on2017-08-31 13:00:33

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