Primerjava vpliva sedimentacije in flotacije mošta na kemijske lastnosti in senzoriko vina

Mlakar, David (avtor), Košmerl, Tatjana (mentor), Košir, Iztok Jože (komentor)

Sedimentacija in flotacija sta najbolj razširjena postopka za bistrenje grozdnega soka pred alkoholno fermentacijo. Namen magistrskega dela je bil ugotoviti vpliv teh dveh postopkov predelave grozdja na kakovost pridelanega vina. V fermentacijskih poskusih smo uporabili kratko maceriran grozdni sok sorte modra frankinja, primeren za proizvodnjo Rose vina. Sok je bil pridelan v vinorodni deželi Podravje, letnik 2019. Polovico grozdnega soka smo bistrili s sedimentacijo, drugo polovico pa s flotacijo, pri čemer smo kot penilno sredstvo uporabili argon. Za gravimetrično spremljanje fermentacije smo nastavili tri paralelke za flotiran in tri za sedimentiran grozdni sok, volumen le-teh je bil 0,5 L. V času fermentacije smo spremljali maso steklenic, iz katere smo preračunali kinetiko in hitrost fermentacije. Po končani fermentaciji smo z aparatom WineScanTM določili kemijske parametre vzorcev. Za senzorično analizo in plinsko kromatografijo smo flotiran in sedimentiran sok fermentirali v štirih fermentacijskih steklenicah po 5 L; v slednje smo med fermentacijo dodajali hranila za kvasovke. Po končani fermentaciji smo vino pretočili, analizirali kemijske parametre (WineScanTM), določili koncentracije hlapnih komponent (plinska kromatografija), senzorično ocenili vzorce in preverili mikrobiološko sestavo droži. Rezultati so pokazali, da imajo sedimentirani in flotirani vinski vzorci podobno kemijsko sestavo. V sedimentiranih vzorcih so se tvorile neželene hlapne spojine, ki so slabo vplivale na senzorično kakovost vina. Vino, pridelano iz flotiranega grozdnega soka, je bilo senzorično boljše ocenjeno (1 točka razlike na Buxbaumovi lestvici).

• Jezik: Slovenski jezik
• Ključne besede: vino, flotacija, sedimentacija, bistrenje, mošt, grozdni sok, vinske kvasovke, alkoholna fermentacija, hlapne spojine, hranila za kvasovke
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: BF - Biotehniška fakulteta
• Kraj izida: Ljubljana
• Založnik: [D. Mlakar]
• Leto izida: 2021
• PID: 20.500.12556/RUL-134076
• UDK: 663.252/.257:663.222:543.92
• COBISS.SI-ID: 89389059
• Datum objave v RUL: 23.12.2021

MLAKAR, David, 2021, Primerjava vpliva sedimentacije in flotacije mošta na kemijske lastnosti in senzoriko vina [na spletu]. Magistrsko delo. Ljubljana : D. Mlakar. [Dostopano 19 maj 2025]. Pridobljeno s: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=slv&id=134076

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Impact of must sedimentation and flotation on chemical and sensory parameters of wine

Izvleček

Sedimentation and flotation are the most common processes for clarifying grape juice prior to alcoholic fermentation. The aim of this Master's thesis was to determine the effects of these two grape processing procedures on the quality of the wine produced. Short-macerated grape juice of the Blaufränkisch variety, which is suitable for the production of rose wine, was used for the fermentation experiments. The juice was produced in the Podravje wine-growing region in vintage 2019. Half of the grape juice was clarified by sedimentation and the other half by flotation, using argon as a foaming agent. For gravimetric monitoring of fermentation, we defined three classes for flotated grape juice and three for sedimented grape juice with a volume of 0.5 L. During fermentation, we monitored the mass of the bottles and used this to calculate the kinetics and rate of fermentation. After fermentation, the chemical parameters of the samples were determined using a WineScanTM instrument. For sensory analysis and gas chromatography, the flotated and sedimented juice was fermented in four 5-litre fermentation bottles to which yeast nutrients were added during fermentation. After fermentation, the wine was racked, the chemical parameters were analysed (WineScanTM), the concentrations of volatile components were determined (gas chromatography), the samples were sensory evaluated, and the microbiological composition of the yeast was checked. The results showed that sedimented and flotated wine samples had similar chemical compositions. Undesirable volatile compounds were formed in the sedimented samples, which had a negative effect on wine sensory quality. The wine produced from flotated grape juice was rated sensory better (1-point difference on the Buxbaum scale).

• Ključne besede: wine, flotation, sedimentation, clarification, must, grape juice, wine yeasts, alcoholic fermentation, volatile compounds, yeasts nutrients