Određivanje tartaratne stabilnosti vina primjenom konduktometrije

master's thesis

• Title (english): Determination of the tartaric wine stability by conductometry application
• Author: Stribor Pocem Mihaljević
• Mentor: Ana Jeromel (mentor)
• Committee member: Ana Jeromel (predsjednik povjerenstva)
• Committee member: Ana-Marija Jagatić Korenika (član povjerenstva)
• Committee member: Luna Maslov Bandić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Agriculture; (Department of Viticulture and Enology); Zagreb
• Defense date and country: 2023-09-26, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Agronomy

Abstract

Vino koje se nalazi na tržištu mora biti kemijski i mikrobiološki stabilno. Prisutnost disocirane i ne disocirane vinske kiseline te kalijevih i kalcijevih iona u vinu glavni su uzročnik potencijalne tartaratne nestabilnosti vina, a koja se manifestira u obliku taloga na dnu boce, koji odbija konzumente od kupnje. U nekim je zemljama indikacija loše vinarske prakse, dok u nekim slučajevima može biti preduvjet za izlazak na tržište. Tartaratna stabilnost vina može se odrediti testom hlađenja, odnosno držanjem vina na -4 °C kroz 72 sata te primjenom konduktometrije po točno definiranom protokolu.
U ovom radu za određivanje tartaratne stabilnosti vina i optimiranje metode za njezino određivanje koristili su se uzorci vina ´Graševina´, berba 2021. proizvođača Kutjevo d.d. Pri tome se koristila masa kalijevog bitartarata (KHT) od 1 g i volumen uzorka vina od 100 mL, a što odgovara koncentraciji KHT od 10 g/L prema prethodno provedenim eksperimentima. Temperaturni raspon mjerenja bio je od 0 do -4 °C. Provodnost u uzorcima se mjerila prije dodavanja KHT-a i nakon 4 min uz kontinuirano miješanje smjese. Promjena provodnost određena je formuli % = {( prije dodatka KHT -  nakon dodatka KHT)/  prije dodatka KHT} x 100%. Utvrđeno je da ako je vrijednost % u slučaju bijelih vina manja od 4% vino se može smatrati stabilnim. Ovaj prag u slučaju crnih vina iznosio je 5%. Cilj rada bio je utvrditi i utjecaj temperature na kristalizaciju soli vinske kiseline i točnost predviđanja stabilnosti vina na tartarate konduktometrijom.

Abstract (english)

The wine which can be found on the market must be chemically and microbiologically stabile. The presence of dissociated and non-dissociated tartaric acid and potassium and calcium ions in the wine are the main cause of potential tartaric instability of wine, which manifest itself in a form of crystal sediment on the bottom of the bottle. This can repel consumers and, in some countries, can be indicator of a bad winemaking practice, while in some instances can be one of the requirements for market appearance of the product. Tartaric stability of wine can be determined true cold storage on the -4°C for 72 hours and with conductometry by the determined protocol.
For the determination of tartaric stability in wine, samples of Graševina wine vintage 2021. made by Kutjevo d.d. were used. The influence of the KHT (potassium hydrogen tartrate) and temperature of the solution on the conductivity was determined with 10 g/L of KHT used in the tests at the range of temperatures from 0 to -4 °C. Conductivity was measured before and after the addition of KHT. The latter measurement was done after 4 min of stirring after the addition. Change in electroconductivity was determined by the formula % = {( before addition KHT –  after addition KHT)/  before addition KHT} x 100%. If the value % in the case of white wines was lower than 4%, the wine can be considered stable on tartrates. In the case of red wines, this threshold is 5%. The goal was also to determine the effect of temperature on the crystallization process and the precision of conductometry in the assessment of tartaric stability of wine.

• Keywords: vinska kiselina; kalcijevi ioni; kalijevi ioni; kalijev bitartarat; konduktometrija
• Keywords (english): tartaric acid; potassium ions; potassium hydrogen tartrate; conductometry
• Language: croatian
• URN:NBN: urn:nbn:hr:204:338539
• Study programme: Title: Horticulture; Study programme type: university; Study level: graduate; Academic / professional title: magistar/ magistra inženjer/inženjerka hortikulture (magistar/ magistra inženjer/inženjerka hortikulture)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-09-28 07:20:56