Določevanje izbranih fizikalno-kemijskih lastnosti vina Chardonnay za strojno učenje

Migan, Melanie (author), Marolt, Gregor (mentor), Markelj, Jernej (comentor)

Vino spada v eno najstarejših in najbolj cenjenih alkoholnih pijač. Pridobiva se ga s fermentacijo grozdnega soka, kjer ni prisotnih dodatkov, kot so encimi, sladkorji ali druga hranila. Vino vsebuje največ etanola in vode, ki sta tudi glavni sestavini vina in hkrati tudi druge številne spojine, kot so sladkorji, organske kisline, vitamini in minerali, ki skrbijo za okus in aromo samega vina. V okviru diplomske naloge sem analizirala in primerjala fizikalno-kemijske lastnosti 79 različnih vzorcev vina Chardonnay. Na podlagi uravnavanja pH sem želela ugotoviti, ali se fizikalno-kemijske lastnosti spreminjajo z dodatkom kisline (HCl) ali baze (NaOH). Pri raziskavi sem uporabila tehniko Fourierjeve transformacijske infrardeče spektroskopije (FT-IR), ki omogoča določevanje funkcionalnih skupin, ki so prisotne v vzorcu glede na absorbirano infrardečo svetlobo pri različnih valovnih dolžinah. Ugotovila sem, da pri različni pH vrednostih ni bilo večjih razlik med spektri, kar bi lahko mogoče pripisala večji prisotnosti etanola in vode ali pa, da dodatek kisline ali baze ne povzroči bistvene strukturne spremembe prevladujočih molekul. Za določitev vsebnosti kovin v vzorcih sem uporabila tehniko Induktivno sklopljene plazme z optičnim emisijskim spektrometrom (ICP-OES). Določevala sem koncentracijo 36 elementov, od tega jih je bilo samo 19 nad mejo zaznave, zato ostalih elementov nisem upoštevala pri analizi. Na podlagi rezultatov, sem vzorce razdelila na tri slovenske pokrajine – Dolenjsko, Primorsko in Štajersko. Za statistično obdelavo podatkov sem uporabila Metodo glavnih osi (PCA) in ugotavljala, ali se glede na različne slovenske pokrajine pridelave vina tudi vsebnost elementov razlikuje, glede na poreklo vina. Večinsko so se vina iz Štajerske in Primorske povezovala v dve skupini, vina iz Dolenjske pa niso tvorila ločene skupine, ampak so prekrivala del vzorcev iz obeh regij. To bi lahko bila posledica drugačne prsti, v kateri raste trta, kar posledično vpliva na elementno sestavo vina in na razlike med posameznimi slovenskimi regijami. Rezultati lahko pripomorejo k boljšemu razumevanju vpliva geografskega porekla na sestavo vina.

• Language: Slovenian
• Keywords: vino, elementna sestava, FT-IR spektroskopija, ICP-OES, PCA analiza
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2025
• PID: 20.500.12556/RUL-170174
• COBISS.SI-ID: 243058435
• Publication date in RUL: 02.07.2025

Secondary language

• Language: English
• Title: Determination of selected physico-chemical properties of wine Chardonnay for machine learning

Abstract

Wine is one of the oldest and most highly valued alcoholic beverages. It is produced by fermenting grape juice without the addition of enzymes, sugars or other nutrients. Wine primarily consists of ethanol and water, which are its main components, but it also contains numerous other compounds such as sugars, organic acids, vitamins and minerals that contribute to its taste and aroma. In this work, I analysed and compared physicochemical properties of 79 different Chardonnay wine samples. By adjusting the pH, the aim was to determine whether the physicochemical characteristics change with the addition of acid (HCl) or base (NaOH). The study employed Fourier Transform Infrared Spectroscopy (FT-IR) to identify the functional groups present in the samples based on the absorption of infrared light at different wavelengths. It was observed that there were no significant differences between the spectra at different pH levels, which could be attributed to the high content of ethanol and water, or the fact that the addition of acid or base does not cause substantial structual changes to the predominant molecules. The concentrations of metals in the samples were determined using Inductively Couples Plasma Optical Emission Spectrometry (ICP-OES). Of the 36 elements analysed, only 19 were above the detection limit and the rest were not included for further analysis. Based on these results, the wine samples were classified according to three Slovenian wine-growing regions – Dolenjska, Primorska and Štajerska. To statistically evaluate the data, Principal Component Analysis (PCA) was used to investigate whether the elemental composition of wine differs depending on its geographical origin. Wines from Štajerska and Primorska generally formed two distinct froups, while wines from Dolenjska did not form a seperate group but rather overlapped with samples from both other regions. This could be due to differences in soil composition where the vines grow, which in turn affects the elemental composition of the wine and contributes to regional differences.

• Keywords: wine, elemental composition, FT-IR spectroscopy, ICP-OES, PCA analysis