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Povzetek V diplomskem delu smo raziskali, če izbrana živila vsebujejo vitamin D2 (ergokalciferol), provitamin D2 (ergosterol), vitamin D3 (holekalciferol) in provitamin D3 (7-dehidroholesterol). Analizirali smo živila rastlinskega izvora: ričkovo olje, konopljino olje, posušeno konopljo, gobe (bukov ostrigar) in lucerno ter živila živalskega izvora: sir, sirotka in jajce (rumenjak in beljak). Živila smo predhodno pripravili za nadaljnje analize. Konopljo in suho lucerno smo zmleli, svežo lucerno in sveže gobe smo liofilizirali, nato zmleli, preostanek svežih gob narezali in zamrznili, prav tako tudi svežo lucerno. Sir in sirotka sta bila proizvedena na Kmetiji Krevh po postopku izdelave poltrdega sira. Jajca proste reje smo uporabili sveža. Konopljo, lucerno in gobe smo ekstrahirali po metodi ekstrakcije po Soxhletu in ekstrakcije s superkritičnim fluidom (CO2). Materialom smo določili vsebnost prostih maščobnih kislin. Ekstrakte in ostale materiale smo saponificirali po postopku za saponifikacijo zaestrenega vitamina D in nato vse vzorce (saponificirane in nesaponificirane) analizirali s tekočinsko kromatografijo z masno spektrometrijo. Znano je, da je vitamin D2 prisoten v rastlinskih živilih, vitamin D3 pa v živalskih. Iz nekaterih virov smo ugotovili, da lahko tudi rastline vsebujejo vitamin D3, ter živalski proizvodi vitamin D2, kar smo potrdili tudi z našimi analizami. Ugotovili smo, da je za določitev vitaminov in provitaminov D potrebna saponifikacija, saj je vsebnost vitamina v saponificiranih vzorcih višja. Rezultati kažejo, da je količina vitamina D, ki je topen v maščobah, povezana z vsebnostjo maščob v materialu, za nekatere primere pa smo sklepali, da je vitamin vezan na proteinske molekule. The diploma thesis examines if the selected food products contain vitamin D2 (ergocalciferol), provitamin D2 (ergosterol), vitamin D3 (cholecalciferol), and provitamin D3 (7-dehydrocholesterol). We have analysed plant-based foods: Camelina sativa oil, hemp oil, dried hemp, oyster mushrooms, and alfalfa, and animal-based foods: cheese, whey, and eggs (the yoke and the white). We prepared the foods for further analyses. The hemp and dried alfalfa were ground, the fresh alfalfa and fresh mushrooms were freeze-dried and ground, the remaining fresh mushrooms were sliced and frozen, as was the fresh alfalfa. The cheese and whey were produced by the Krevh farm according to the process of producing semi-hard cheese. Free-range eggs were used fresh. The hemp, alfalfa, and mushrooms were extracted using Soxhlet extraction and supercritical fluid extraction (CO2). We determined the content of free fatty acids in the materials. The extracts and other materials were saponificated using the process of saponificating esterificated vitamin D. All samples (both saponificated and non-saponificated) were analysed using fluid chromatography with mass spectrometry. It is known that vitamin D2 is present in plant-based foods, while vitamin D3 is present in animal-based foods. In some sources we found that even plants may contain vitamin D3 and that animal products may contain vitamin D2, which our analyses also confirmed. We found that saponification is required to establish the presence of vitamins and provitamins D, because the vitamin content in saponificated samples is higher. Results indicate that the amount of fat-soluble vitamin D is correlated to the fat content of the material, while for some examples we assumed that the vitamin is bound to protein molecules. |
