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Title:VSEBNOST POLIFENOLOV V OLJU GROZDNIH PEŠK
Authors:ID Koron, Enej (Author)
ID Mozetič Vodopivec, Branka (Mentor) More about this mentor... New window
Files:.pdf Enej_Koron.pdf (1,48 MB)
MD5: 3A63B6E58738E0AE49524C258BD6BB2E
 
Language:Slovenian
Work type:Bachelor thesis/paper
Typology:2.11 - Undergraduate Thesis
Organization:FVV - School for Viticulture and Enology
Abstract:Diplomska naloga obravnava pridobivanje olje iz grozdnih pešk s hladnim stiskanjem. V nalogi smo izvedli postopek izolacije in priprave pešk na stiskanje na kmetiji (ne v laboratoriju), samo stiskanje olja na hladen način oz. brez dodatnega segrevanja v vijačni stiskalnici, ki je bila razvita za tako zahtevna semena kot so grozdne peške. V nalogi smo primerjali stiskanje pešk in tudi olje pešk štirih belih sort grozdja 'Pinela', 'Beli pinot', 'Laški rizling', 'Sauvignon' in dveh rdečih sort 'Cabernet sauvignon' in 'Refošk'. Sorte so se zelo malo razlikovale v izplenu olja, ki je znašal v povprečju 9 masnih %, kar je bilo nekoliko manjše kot pri drugih objavah v literaturi – kar je mogoče posledica sezone, pa tudi mehanskega stiskanja, za katerega je iz literature znano, da ima najmanjši izplen – v primerjavi z drugimi metodami ekstrakcije olja. Analiza olja je pokazala prisotnost raznolikih fenolnih spojin - različnih nizkomolekularnih tanininov – procianidinov B1, B2, C1, fenolnih kislin kot je galna kislina, protokatehinska kislina, kavna kislina, klorogenska kislina, p-kumarna kislina in flavonolov katehina in epikatehina. Seštevek vseh kromatografsko določenih fenolnih spojin je variral od 3,75 μg/g pri olju Pinela pa do 9,98 μg/g v olju Refošk. Pri skupnih fenolih, določenih po metodi Folin-Ciocalteu pa od 14,08 μg (kot galna kislina)/g (olje Sauvignon) pa do 35,23 μg (kot galna kislina)/g (olje Refošk). V olju različnih sort so vsebnosti skupnih in posameznih fenolov zelo varirale, na splošno pa smo ugotovili, da mehansko pridobljeno olje pešk rdečih sort vsebuje v povprečju vsebuje tudi do dvakrat večje koncentracije skupnih fenolov kot olje belih sort. Ugotovili smo, da v povprečju v procesu mehanskega stiskanja prehaja v olje zgolj 0,02 % vseh prisotnih fenolnih spojin, torej večina ostane v pogači, ki bi jo lahko še nadalje uporabili ne le kot vir beljakovin, ampak tudi kot vir polifenolov.
Keywords:olje, grozdne peške, Vitis vinifera L., fenoli, mehansko stiskanje olja
Place of publishing:Nova Gorica
Year of publishing:2023
PID:20.500.12556/RUNG-8373 New window
COBISS.SI-ID:163598339 New window
NUK URN:URN:SI:UNG:REP:OKYJTSJV
Publication date in RUNG:07.09.2023
Views:1777
Downloads:26
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Licences

License:CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Link:http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:29.08.2023

Secondary language

Language:English
Title:POLYPHENOL CONTENT IN GRAPE SEED OIL
Abstract:The work deals with the extraction of grape seed oil obtained by cold pressing. In this work we have carried out the isolation and preparation of the seeds for pressing on the farm (not in the laboratory) with the cold pressing of the oil without additional heating in a screw press designed for such challenging seeds for pressing as grape seeds. In this work we compared the pressing of the seeds and also the chemical composition of grape seed oil of four white grape cultivars 'Pinela', 'Pinot Blanc', 'Riesling', 'Sauvignon' and two red grape cultivars 'Cabernet Sauvignon' and 'Refošk'. The cultivar seeds differed only slightly in the oil yield, which averaged 9 % by weight, slightly lower than in other reports in the literature - possibly due to seasonal variation (climatic conditions), but also due to mechanical pressing, which is known to have the lowest yield from such seeds - compared to other methods of oil extraction from grape seeds. Analysis of the oil showed the presence of a variety of phenolic compounds in the oil - various low molecular weight tannins - procyanidins B1, B2, C1, phenolic acids - gallic acid, protocatechuic acid, caffeic acid, chlorogenic acid, p-coumaric acid, and flavonols catechin and epicatechin. The sum of all phenolic compounds determined by chromatography varied from 3.75 μg/g in Pinela oil to 9.98 μg/g in Refošk oil, and for total phenols determined by the Folin-Ciocalteu method from 14.08 μg (as gallic acid)/g (Sauvignon oil) to 35.23 μg (as gallic acid)/g (Refošk oil). The values of total and individual phenol concentration per gram of oil varied considerably among the different grape cultivars, but in general we found that the grape seed oil of red cultivars on average contained up to twice higher concentrations of total phenols as those of the white cultivars. We found that, on average, only 0.02% of the total phenolic compounds present pass from grape seeds into the oil during the mechanic pressing process, i.e., most of them remain in the cake, which could be further used not only as a source of protein but also as a source of polyphenols.
Keywords:oil, grape seed, Vitis vinifera L., phenols, mechanical oil pressing


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