20.500.12556/RUL-189898 Kvantifikacija polifenolov in etanola pred in po dealkoholizaciji rdečih vin Quantification of polyphenols and ethanol before and after dealcoholization of red wines Rdeče vino je bogat vir fenolov z antioksidativnimi lastnostmi, ki imajo pozitivne učinke na zdravje in dolgoživost. Antioksidante v rdečem vinu delimo na flavonoide (flavan-3-oli, antocianin, flavonoli), fenolne kisline, stilbene ter tanine. Zmerno uživanje rdečega vina vpliva na srčno-žilni sistem, deluje nevroprotektivno, protivnetno in zmanjša tveganje za kronične bolezni. Kljub koristim pa ima tudi slabosti, saj vsebuje alkohol, ki škoduje zdravju. Zato je smiselno za izdelavo prehranskega dopolnila z vsebnostjo polifenolov uporabiti dealkoholizirano vino. Za proces dealkoholizacije smo pri našem delu uporabili metodo izhlapevanja topila pri znižanem tlaku z rotacijskim uparjalnikom. V prvem delu smo z jedrsko magnetno resonanco določali vsebnost etanola v vzorcih izbranih vin in vzorcih vin po postopku dealkoholizacije ter s tem ugotavljali učinkovitost dealkoholizacije. Vsebnost etanola smo izmerili tudi pri vzorcih komercialno dostopnih brezalkoholnih vin in primerjali vsebnost z našimi delno dealkoholiziranimi vzorci. Komercialno dostopnima brezalkoholnima vinoma smo izmerili vsebnosti 0,20 in 0,21 vol. %, delno dealkoholiziranim pa v razponu od 1,72 (Merlot) do 6,44 vol. % (L’Abbaye Chinon). Rezultati metode NMR so kazali na sistematično pozitivno pristranskost, saj je metoda vrednosti dosledno precenjevala. Ugotovili smo, da pri procesu dealkoholizacije 150 g vina pri temperaturi 40 °C in znižanem tlaku 40 mbar po dveh urah še nismo dosegli želene vsebnosti pod 0,50 vol. %, saj je naš vzorec Kabernet (VinaKoper) po koncu postopka vseboval 0,99 vol. %. Delno dealkoholizirane vzorce smo shranjevali v temnem prostoru in merili morebitne spremembe pH vrednosti, kar bi nakazovalo na spremembo v kvaliteti, v intervalu 30 dni. Ugotovili smo, da se pH ni bistveno spremenil. V nadaljevanju smo določali še indeks skupnih polifenolov (TPI), skupno vsebnost polifenolov (TPC), ki jo izrazimo kot ekvivalenti galne kisline na liter. Najbolj primeren vzorec vina glede na ocenjene parametre je bil Refošk (VinaKoper) z visokima TPI (81,5) in TPC (3256 mg GAE/L) vrednostma, kar pomeni, da ima najvišjo vsebnost polifenolov. Ostala vina so imela TPI vrednosti med 37 in 80, vrednosti TPC pa med 1900 in 2800 mg GAE/L. Red wine is a rich source of phenols with antioxidant properties that positively affect health and longevity. The antioxidants in red wine are classified into flavonoids (flavan-3-ols, anthocyanins, flavonols), phenolic acids, stilbenes, and tannins. Moderate consumption of red wine influences the cardiovascular system, exerts neuroprotective and anti-inflammatory effects, and reduces the risk of chronic diseases. However, despite these benefits, it also has drawbacks, as it contains alcohol, which is detrimental to health. Therefore, it is sensible to use dealcoholized wine for the production of polyphenol-rich dietary supplements. For the dealcoholization process, we employed solvent evaporation under reduced pressure using a rotary evaporator. In the first part of the study, we used nuclear magnetic resonance (NMR) spectroscopy to determine the ethanol content in samples of selected wines and in samples subjected to a dealcoholization process, thereby assessing the efficiency of the dealcoholization. We also measured the ethanol content of commercially available non-alcoholic wines and compared these values with those of our partially dealcoholized samples. The commercially available non-alcoholic wines showed ethanol contents of 0.20% and 0.21% (v/v), whereas the partially dealcoholized samples ranged from 1.72% (Merlot) to 6.44% (v/v) (L’Abbaye Chinon). The NMR results indicated a systematic positive bias, as the method consistently overestimated the values. We found that dealcoholizing 150 g of wine at 40 °C and a reduced pressure of 40 mbar for two hours did not achieve the target ethanol content of below 0.50% (v/v); the Cabernet sample (VinaKoper) retained an ethanol content of 0.99% (v/v) after the process. The partially dealcoholized samples were stored in the dark, and we monitored changes in pH—an indicator of quality alteration—over a 30-day period. We found no significant change in pH. Subsequently, we determined the Total Polyphenol Index (TPI) and the Total Polyphenol Content (TPC), the latter expressed as gallic acid equivalents per liter. Based on the evaluated parameters, the most suitable wine sample was Refošk (VinaKoper), with high TPI (81.5) and TPC (3256 mg GAE/L) values, indicating the highest polyphenol content. The other wines had TPI values ranging from 37 to 80 and TPC values between 1900 and 2800 mg GAE/L. polifenoli rdeče vino NMR TPC TPI polyphenols red wine NMR TPI TPC true false false [S. Glatz] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-10-18 08:45:10 2026-10-18 08:45:19 2026-10-20 09:50:40 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1970-01-01 615(043.2) 133394 301630723 36073.pdf 36073.pdf 1 DD3BF7360863B20529D8B1114D3249DD 893f109769c23d6d3e254a371e72c298d7804c727cf4d7bf0266bd24b24b88c3 4e21d543-cabf-11f1-8bc5-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=250806 Fakulteta za farmacijo 0 0 0