Promjene polifenolnog sastava sorte Teran tijekom dozrijevanja grožđa

master's thesis

• Title (english): Changes in the polyphenols content in Teran variety during ripening
• Author: Irena Gržentić
• Mentor: Karin Kovačević Ganić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); Zagreb
• Defense date and country: 2009-03-23, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Polifenoli su jedni od najvažnijih sastojaka vina i direktno su povezani sa bojom, trpkošću, gorčinom i antioksidacijskim karakteristikama, poznatim po pozitivnom utjecaju na zdravlje. Cilj ovog rada bio je odrediti polifenolni sastav grožđa sorte Teran tijekom njegovog dozrijevanja. Smatra se da jedino grožđe sa visokim i balansiranim razinama polifenola može dati kvalitetno crno vino prikladno za starenje. Istraživanja su provedena na 36 uzoraka ekstrakta pokožice grožđa sorte Teran. Grožđe je brano na dvije lokacije, Kosinožići (Vinogorje Zapadna Istra) i Motovun (Vinogorje Centralna Istra), u 6 navrata i u 3 repeticije (18 ekstrakata pokožice), u intervalu od mjesec dana. U ovom su radu na uzorcima provedene spektrofotometrijske metode i određen udio ukupnih polifenola, ukupnih antocijana, flavanola, hidroliziranih tanina, procijanidina, te intenzitet i nijansa boje. Istraživanje je pokazalo da udio polifenolnih spojeva tijekom dozrijevanja pokazuje blagu tendenciju rasta ili kod pojedinih spojeva ostaje na istoj razini uz manje varijacije. Također se pokazalo da uzorci sa područja Motovuna (Vinogorje Centralna Istra) imaju veći udio polifenolnih spojeva u odnosu na one s područja Kosinožića (Vinogorje Zapadna Istra).

Abstract (english)

Polyphenols are among the most important ingredients of wine and are directly interrelated with the colour, bitterness, acerbity and antioxidative properties, known for their positive impact on the health. The objective of this research is to determine how much the polyphenols content is dependant on the level of ripeness. It is maintained that only the grapes containing high and balanced level of polyphenols can yield high-quality red wine which is suitable for maturing. The research has been made on 36 samples of the extract of grape skin of the Teran variety. The grapes were harvested at locations Kosinožići (Western Istria vineyards) and Motovun (Central Istria vineyards), in six occasions and in three repetitions (18 extracts of grape skin), at month interval. In this work spectrophotometric methods have been used for the determination of the polyphenols content in the samples, the total content of anthocyans, flavanols (vanillin index), hydrolyzed tannins, procyanidins, the colour intensity and colour hue. The research has shown that the content of polyphenol substances during ripening tends to grow slightly or it remains the same in particular varieties, with minor variations. It has also been shown that the samples from the Motovun region (Central Istria vineyards) contain higher levels of polyphenol substances in comparison to those from the area of Kosinožići (Central Istria vineyards).

• Keywords: Teran; pokožica; polifenoli; antocijani
• Keywords (english): Teran; skin; polyphenols; anthochyanins
• Language: croatian
• URN:NBN: urn:nbn:hr:159:296854
• 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
• Created on: 2017-08-31 09:23:30