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Title:Fenolni potencial izbranih vin s podaljšano maceracijo sorte "Rebula"
Authors:ID Mozetič Vodopivec, Branka, Fakulteta za vinogradništvo in vinarstvo (Mentor) More about this mentor... New window
ID Bavčar, Dejan, Kmetijski inštitut Slovenije (Author)
ID Popova, Yelyzaveta (Author)
Files:.pdf Diplomska_YP_Final_(1)_KV_BMV23062023_repozitorij.pdf (1,39 MB)
MD5: 1107C1124DDFE9E2EC277C8996B8A946
 
Language:Slovenian
Work type:Bachelor thesis/paper
Typology:2.11 - Undergraduate Thesis
Organization:FVV - School for Viticulture and Enology
Abstract:V diplomski nalogi smo analizirali 30 vzorcev vin sorte grozdja Vitis vinifera L. cv. 'Rebula' iz Vipavske doline in Goriških brd. Vina smo kupili na trgu, in sicer v specializiranih lokalnih prodajalnah vina, spletnih prodajalnah ali pri vinarjih. Osemindvajset (28) vzorcev vina je bilo pridelanih s postopkom podaljšane maceracije drozge grozdja. Dve vini pridelanih brez maceracije, smo dodali v nabor vzorcev zaradi primerjave fizikalno-kemijskih parametrov z ostalimi vzorci. V vinskih vzorcih smo izmerili naslednje standardne fizikalno-kemijske parametre: skupni in prosti žveplov dioksid, skupne titrabilne kisline, pH, hlapne kisline z destilacijsko metodo, izbrane organske kisline, sladkorje (glukozo + fruktozo), etanol in barvo vina s spektofotometrom - absorbanco pri 420 nm (A420) in barvne parametre v CIE Lab sistemu. Izmerili smo tudi skupne polifenole po spektrofotometrijski metodi Folin-Ciocalteu in izbrane posamezne polifenole (hidroksibenzojske kisline, nezaestrene hidroksicimetne kisline, procianidine) s tekočinsko kromatografijo visoke ločljivosti, sklopljeno z UV detetktorjem (HPLC-UV). Želeli smo določiti polifenolni potencial vin sorte 'Rebula', pridelanih s postopkom podaljšane maceracije drozge grozdja in nato določiti morebiten vpliv časa maceracije na količino polifenolov v vinu. Kemijske analize so pokazale veliko variabilnost v količini skupnih polifenolov, ki pa jih nismo uspeli povezati s časom maceracije. Pomanjkljivi podatki o času in drugih pogojih maceracije drozge grozdja nam tega niso dopuščali. Podatki nakazujejo trend večjih koncentracij skupnih polifenolov vina pri vinih, pridelanih s postopkom podaljšane maceracije drozge grozdja. V določenih vinih smo izmerili tudi preko 1000 mg/L (kot galna kislina) skupnih polifenolov. Med posameznimi polifenoli je bilo v vinih največ galne kisline (tudi do 90 mg/L), procianidina B1 (do 52 mg/L) in katehina (do 18 mg/L). Instrumentalno določena barva filtriranega vina (A420 in parametri CIE Lab) je povezana s količino skupnih polifenolov po metodi Folin-Ciocalteu. Parametri barve dolgo maceriranih vin se močno razlikujejo od vin brez maceracije oziroma od vin, pridelanih s krajšim časom maceracije, zato gre za dobre 'markerje' tovrstnih vin. Opazili smo, da kombinacija običajnega parametra barve belih vin A420 nm s parametri CIE Lab sistema omogoča podrobnejšo analizo barve vina.
Keywords:Vitis vinifera L. cv. ‘Rebula’, belo grozdje, belo vino, postopek maceracije, polifenoli
Place of publishing:Nova Gorica
Publisher:Univerza v Novi Gorici
Year of publishing:2023
PID:20.500.12556/RUNG-8025 New window
COBISS.SI-ID:158031363 New window
NUK URN:URN:SI:UNG:REP:S7WLMJ6I
Publication date in RUNG:06.07.2023
Views:2767
Downloads:41
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Secondary language

Language:English
Title:PHENOL POTENTIAL OF SELECTED LONG MACERATED 'REBULA' CULTIVAR WINES
Abstract:We analyzed 30 samples of wines of the grape variety Vitis vinifera L. cv. 'Rebula' from the Vipava Valley and the Goriška Brda. We purchased the wines on the market, either from the local wine stores and online or directly from the winemakers themselves. Twenty-eight (28) wine samples were made with prolonged maceration of the grape marc. Additional two wines made without maceration were added to the sample group to compare the physicochemical parameters with those of the other samples. The following standard physicochemical parameters were measured in the wines: total and free sulfur, total titratable acids, pH, volatile acids by the distillation method, organic acids, sugars (glucose + fructose), ethanol, and wine color measured spectrophotometrically at absorbance wavelength of 420 nm (A420) and color parameters in the CIE Lab system. We also deteremined the total phenols using the Folin−Ciocalteu method and selected individual phenols (hydroxybenzoic acids, non-esterified hydroxycinnamic acids, procyanidins) by using high performance liquid chromatography coupled with UV detector (HPLC-UV). We aimed to determine the phenolic potential of macerated wines of the 'Rebula' variety and at the same time we wanted to determine the possible influence of maceration time on the amounts of phenols in the wine. Chemical analysis showed high variability in total phenolic concentrations among samples, anyhow we were unable to correlate them statistically with maceration time due to insufficient data on the duration and other conditions of prolonged maceration of grape marc. The data suggest a tendency toward higher concentrations of wine polyphenols in wines produced by prolonged maceration of grape marc. Polyhenols contentration over 1000 mg/L (as gallic acid equivalents) was measured in some wines, namely, gallic acid (up to 90 mg/L), procyanidin B1 (up to 52 mg/L), and catechin (up to 18 mg/L) were the most abundant polyphenols in the wines. The instrumentally determined color of filtered wine is related to the amounts of total phenols determined by the Folin−Ciocalteu method. The color parameters of wines without maceration and of wines with shorter maceration time were very different from the long-macerated wine samples, which indicates them to be good 'marker’ parameters for such wines. A combination of the common white wine color parameter A420 with the CIE Lab system allows a more detailed analysis of wine color.
Keywords:Vitis vinifera L. cv. 'Rebula', white grapes, white wine, maceration process, polyphenols


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