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Title:VPLIV KOVINSKIH IONOV NA IZGUBO SADNE AROMATIKE MLADIH BELIH VIN
Authors:Ferjančič, Matic (Author)
Antalick, Guillaume (Mentor) More about this mentor... New window
Files:.pdf Matic_Ferjancic.pdf (1,43 MB)
 
Language:Slovenian
Work type:Undergraduate thesis (m5)
Tipology:2.11 - Undergraduate Thesis
Organization:FVV - School for Viticulture and Enology
Abstract:Zaradi dejstva, da se kar nekaj slovenskih svežih belih vin že v kratkem obdobju po trgatvi sooča s posledicami netipičnega staranja (ATA), ki se kaže predvsem v hitri izgubi intenzivne sadne aromatike, smo se odločili, da bomo v diplomskem delu raziskali vzroke, ki pripeljejo do tega vedno bolj perečega problema. Ob preučevanju literature, povezane s to tematiko, smo naleteli na podatke, da bi lahko bila izguba intenzivne sadne aromatike (hidroliza estrov) povezana s povečanimi vsebnostmi kovinskih ionov v vinih. Poleg tega smo zasledili tudi raziskave, v katerih raziskovalci dokazujejo, da večja vsebnost antioksidantov v vinih pomaga zaščititi sadne estre. Da bi te informacije preverili, smo se odločili narediti poskus, v katerem smo v različnih obravnavanjih v vino sorte Sauvignon dodali realne količine kovinskih ionov in antioksidantov. Tako pripravljene vzorce smo nato pospešeno starali 50 dni pri 30 °C. Po koncu staranja smo estre iz vzorcev ekstrahirali z dietil etrom in te ekstrakte analizirali z uporabo plinskega kromatografa s plamenskim ionizacijskim detektorjem (GC-FID). Ugotovili smo, da kovinski ioni vplivajo na zmanjšanje količine estrov v izbranem vinu. Ravno tako smo ugotovili, da večja vsebnost antioksidantov v vinu, ki vsebuje več kovinskih ionov, pomaga zmanjšati hidrolizo estrov. Tekom izvedbe poskusa smo se soočili s kar nekaj ovirami in tako spoznali, da za pospešeno staranje vzorcev za analizo estrov ni primeren vsak material posodic. Pri stekleničkah smo opazili, da je med uporabo novega in opranega rabljenega stekla po 50-dnevnem staranju velika razlika v vsebnosti estrov v vzorcih. Možno je, da se med staranjem iz natrijevega borosilikatnega stekla v vino ekstrahirajo kovinski ioni, ki na tak način kontaminirajo vzorce. Pri polipropilenski (PP) embalaži pa smo opazili, da se med staranjem količina estrov v vzorcih zmanjša bolj kot v opranem rabljenem steklu. Vzrok za to je najverjetneje v adsorpciji estrov na stene PP posode.
Keywords:vino, estri, kovinski ioni, antioksidanti, ATA, plinski kromatograf s plamenskim ionizacijskim detektorjem, GC-FID, izguba sadne aromatike, vpliv materiala embalaže na hidrolizo estrov
Year of publishing:2020
Source:Nova Gorica
COBISS_ID:23895043  Link is opened in a new window
URN:URN:SI:UNG:REP:KTF0UPDN
Views:366
Downloads:15
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Secondary language

Language:English
Title:INFLUENCE OF METAL IONS ON THE LOSS OF FRUIT AROMA OF YOUNG WHITE WINES
Abstract:Quite a few Slovenian fresh white wines begin to show the effects of atypical aging (ATA) in the short period after the harvest, which is reflected in the rapid loss of intense fruity aroma. Based on these findings we decided to investigate the causes of this pressing problem in the present dissertation. During the literature examination, we came across the information that the loss of the intense fruit aromas (ester hydrolysis) could be related to the increased content of metal ions in those kinds of wines. Moreover, we found various researches showing that higher levels of antioxidants in wines help protect fruit esters. Therefore, we did multiple trials of experiments in which we tested adding real quantities of metal ions and antioxidants to the Sauvignon wine. These samples were then rapidly aged for 50 days at 30 degrees Celsius. After aging, the esters from the samples were extracted with diethyl ether, and then we analyzed those using a gas chromatograph with a flame ionization detector (GC-FID). We found out that metal ions can influence the reduction of quantity of esters in selected wine. Furthermore, we found out that higher content of antioxidants in wines with higher metal ion content, can helps reduce ester hydrolysis. During the experiment, we faced several obstacles and established that not every material of container is suitable for accelerated aging of samples for ester analysis. In the glass bottle experiment, we noticed that there was a large difference in the content of esters in samples aged 50 days between the use of new and used glass. Moreover, it is possible that metal ions are extracted from the sodium borosilicate glass during the aging, therefore, contaminating the samples. In the experiment of polypropylene (PP) packaging, we established that during aging the number of esters in the samples decreased more than in the experiment of used glass. The cause for that is most likely in the absorption of esters on the walls of the PP container.
Keywords:wine, esters, metal ions, antioxidants, ATA, gas chromatograph with flame ionization detector, GC-FID, loss of fruit aroma, influence of storage material on ester hydrolysis


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