Repozitorij Univerze v Novi Gorici

Iskanje po repozitoriju
A+ | A- | Pomoč | SLO | ENG

Iskalni niz: išči po
išči po
išči po
išči po
* po starem in bolonjskem študiju

Opcije:
  Ponastavi


1 - 10 / 16
Na začetekNa prejšnjo stran12Na naslednjo stranNa konec
1.
2.
3.
KEMIJSKA IN SENZORIČNA ANALIZA TIPIČNIH AROMATIČNIH LASTNOSTI VIN SORTE 'MODRA FRANKINJA'
Urban Hlade, 2023, diplomsko delo

Opis: 'Modra frankinja' (Vitis vinifera L.) je tradicionalna slovenska sorta grozdja, a kljub temu Slovenci o njej nismo dovolj seznanjeni. Tudi ko gledamo širši vinski svet, opazimo, da o tej sorti in njenih značilnostih vemo zelo malo. Po naših podatkih aromatične tipičnosti vin sorte 'Modra frankinja' še niso bile raziskane. Diplomsko delo je prva tovrstna raziskava te sorte. V delu smo želeli raziskati aromatične lastnosti vin te sorte s pomočjo neformalne senzorične analize. Na ta način smo povzeli katere senzorične note so na splošno izrazite pri obravnavani sorti vina. V nadaljevanju smo s kemijsko analizo aromatičnih spojin vzorcev vina to še kemijsko ovrednotili. Pri kemijski analizi smo se osredotočili na štiri skupine spojin, ki po našem mnenju krojijo tipičnost arom vin sorte 'Modra frankinja'. To so: monoterpeni, estri, norizoprenoidi in C6-alkoholi. Rezultati kažejo, da so prav predstavniki skupine terpenov tisti, ki se pojavljajo v največjih koncentracijah v obravnavanih vinih in pomembno krojijo aromatični profil vin 'Modra frankinja'. C13-norizoprenoidi so bili prisotni v večjih koncentracijah pri vzorcih sortnega vina 'Modra frankinja', kot pri vinih 'Modri pinot' ali vinih bordojskih sort. A še vedno vsebnosti C13-norizoprenoidi ostajajo precej manjše od zaznavnih senzoričnih pragov teh spojin.
Ključne besede: Vino, vitis vinifera L. 'Modra frankinja', kemijska analiza, estri, terpeni, norisoprenoidi, C6-alkoholi, plinski kromatograf, GC-MS.
Objavljeno v RUNG: 04.07.2023; Ogledov: 843; Prenosov: 15
.pdf Celotno besedilo (1,91 MB)

4.
Biogenic amines in Hardanger ciders : the effect of native cider yeasts on biogenic amine production
Urban Česnik, Mitja Martelanc, Branka Mozetič Vodopivec, Ingunn Ovsthus, Lorena Butinar, 2023, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: The presence of bioactive compounds in food and beverages of plant origin is mainly connected with higher nutritional value and better sensory properties. However, some of them can pose a threat to food product quality and human health. For example, excess biogenic amines (BAs) intake can cause different allergenic responses in individuals who have such intolerances. BAs have been intensively studied in recent years, especially in fermented foods like wine, meat, fish, and cheese. Among fermented beverages is apple cider still rather unexplored from this perspective. Especially since no such data exist for the Norwegian cider. Norwegian cider is becoming more and more popular in Norway in recent years among producers and consumers. Hardanger cider from Western Norway is very different from French, English, or Spanish ciders in terms of sensory characteristics, apple cultivars, and in the fermentation process. In Hardanger, the traditional cider is still produced by spontaneous fermentation of apple juice with naturally occurring yeasts that originate from the fruit or processing equipment surfaces. Lactic acid bacteria are known to be associated with BA formation. However, several studies reported about the BA-producing yeasts in winemaking. Due to the important role of natural yeasts in the production of Hardanger cider, we focused on the ability of BA formation by native yeasts. Thus, in our study, we followed the amounts of BAs in the Hardanger ciders during the fermentation process and characterize isolated yeasts if they have the ability to produce BAs under cidermaking conditions by performing a micro-fermentation experiment. From must/cider samples, taken during the fermentation process at 13 producers in the Hardanger region, we isolated 530 yeast isolates. Based on the sequencing of the D1/D2 domain of the 26S rDNA we identified 25 different yeast species. As expected, yeast diversity was higher at the beginning compared to the middle fermentation stage, when mostly different non-Saccharomyces yeast species prevailed, while at the end of fermentation mainly Saccharomyces species with high ethanol tolerance were present. BAs were analyzed with the HPLC-UV method. In all apple juice/cider samples 4 different BAs (putrescine, cadaverine, histamine, and tyramine) were detected and quantified with external calibration. On average in all cider samples from the producers total BA (summation of all BAs) concentration reached 9,45 mg/L, however in one case even 25 mg/L. Tyramine was the most abundant BA in all fermentation stages. 40 isolated yeast strains were further tested for BA formation in a small-scale experiment by fermenting apple juice. Results show that non-Saccharomyces yeasts mainly form histamine (1,68 mg/L) and tyramine (1,30 mg/L), while Saccharomyces yeasts putrescine (0,48 mg/L) and tyramine (3,53 mg/L). As a general conclusion, the occurrence and distribution of BA concentrations in the small-scale fermentation were lower (2,96 mg/L and 4,01 mg/L) and less variable than in the real ciders (average in final ciders 9,45 mg/L) and with tyramine being the most abundant BA in all samples analyzed.
Ključne besede: cider, yeast, biogenic amines, Hardanger, biodiversity
Objavljeno v RUNG: 23.06.2023; Ogledov: 864; Prenosov: 5
URL Povezava na datoteko
Gradivo ima več datotek! Več...

5.
6.
Cider yeasts associated with Hardanger cider during fermentation process
Urban Česnik, Mitja Martelanc, Branka Mozetič Vodopivec, Ingunn Ovsthus, Lorena Butinar, 2022, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: In the Hardanger area in Western Norway, the production of cider has a long tradition that goes back to the 12th century, when monks introduced apple growing in this area. Nowadays, this is also the main area of fruit production in Norway. Despite the strict regulation of the alcoholic beverage production in Norway, traditional cider is still produced on some farms in this area. Therefore, our aim was to study the ecology and biodiversity of the yeasts associated with the cider production in the Hardanger area during fermentation process; especially of traditional cider, which is produced by a spontaneous fermentation of apple juice, performed by naturally occurring indigenous yeasts that originate from the fruit or the surfaces of the processing equipment. In our study, samples of fermenting juice/cider were taken during fermentation process from 12 producers, located in 12 different locations in Hardanger region. Classical cultivation methods using WL (Wallerstein Laboratories) agar medium with added chloramphenicol enable us to isolate a total of 530 yeast isolates that were stored in in-house yeast collection at the NIBIO and included also at the Wine Research Centre collection. Based on the sequencing of the D1/D2 domain of the 26S rDNA we managed to identify 357 isolates and distinguished 27 different yeast species as follows: Aureobasidium pullulans, Candida californica, C. oleophila, C, sake, Hanseniaspora meyeri, H. uvarum, H. valbyensis. Kregervanrija fluxuum, Kregervanrija sp., Metschnikowia andauensis, M. chrysoperlae, M. fructicola, M. pulcherrima, Metschnikowia sp, Pichia fermentans, P. kluyveri, P. membranifaciens, P. nakasei, Piskurozyma capsuligena, Rhodotorula nothofagi, Saccharomyces bayanus, S. cerevisiae, S. paradoxus, S. pastorianus, Saccharomyces sp., S. uvarum and Torulaspora delbrueckii. Even though we were not able to obtain samples in three different fermentation stages (beginning, middle and at the end of fermentation) from all producers, we could observe yeast succession during fermentation progress. Yeast diversity was higher at the beginning comparing to the middle of fermentation, when mostly different non-Saccharomyces yeast species prevailed, while in the middle of fermentation 11 species were detected (Candida californica, H. uvarum, H. valbyensis, Kregervanrija sp., K. fluxuum, Pichia membranifaciens, Metschnikowia pulcherrima, Saccharomyces sp, S. bayanus, S. uvarum and S. cerevisie). On the other hand, at the end of fermentation mainly Saccharomyces species with high ethanol tolerance were present (Saccharomyces sp., S. cerevisiae, bayanus, S. uvarum and P. fermentans). In samples that were collected from three producers in all three fermentation stages also quality parameters were determined (ethanol, organic acids, sugars, biogenic amines) with in-house developed methods using HPLC-UV/RID. The most important sugars in ciders were fructose and glucose, as expected. Two producers added sugar to increase the level of ethanol in the middle of fermentation, which is a common procedure in the Hardanger area. Ethanol and organic acid analysis indicated that fermentations went in the right direction, since all parameters were within normal limits. Including the acetic acid level, an indicator of low cider quality, was very low (average around 0,06 g/L). The alcohol incised from the beginning to end fermentation in all samples analysed and minimum concentration was 2,71 g/L. In ciders we detected four biogenic amines (putrescin, cadaverine, histamine and tyramine). The average amount was 32 mg/L and the most abundant was tyramine.
Ključne besede: indigenous yeasts, biodiversity, spontaneous fermentation, cider-making
Objavljeno v RUNG: 18.10.2022; Ogledov: 1106; Prenosov: 0
Gradivo ima več datotek! Več...

7.
Characterization of electrochemical processes in metal-organic batteries by X-ray Raman spectroscopy
Ava Rajh, Iztok Arčon, Klemen Bučar, Matjaž Žitnik, Marko Petric, Alen Vižintin, Jan Bitenc, Urban Košir, Robert Dominko, Hlynur Gretarsson, Martin Sundermann, Matjaž Kavčič, 2022, izvirni znanstveni članek

Opis: X-ray Raman spectroscopy (XRS) is an emerging spectroscopic technique that utilizes inelastic scattering of hard Xrays to study X-ray absorption edges of low Z elements in bulk material. It was used to identify and quantify the amount of carbonyl bonds in a cathode sample, in order to track the redox reaction inside metal−organic batteries during the charge/ discharge cycle. XRS was used to record the oxygen K-edge absorption spectra of organic polymer cathodes from different multivalent metal−organic batteries. The amount of carbonyl bond in each sample was determined by modeling the oxygen K-edge XRS spectra with the linear combination of two reference compounds that mimicked the fully charged and the fully discharged phases of the battery. To interpret experimental XRS spectra, theoretical calculations of oxygen K-edge absorption spectra based on density functional theory were performed. Overall, a good agreement between the amount of carbonyl bond present during different stages of battery cycle, calculated from linear combination of standards, and the amount obtained from electrochemical characterization based on measured capacity was achieved. The electrochemical mechanism in all studied batteries was confirmed to be a reduction of double carbonyl bond and the intermediate anion was identified with the help of theoretical calculations. X-ray Raman spectroscopy of the oxygen K-edge was shown to be a viable characterization technique for accurate tracking of the redox reaction inside metal−organic batteries.
Ključne besede: X-ray Raman spectroscopy, meta-organic batteries, oxygen K-edge XANES, electrochemical processes
Objavljeno v RUNG: 24.03.2022; Ogledov: 1624; Prenosov: 20
URL Povezava na celotno besedilo
Gradivo ima več datotek! Več...

8.
Življenje in delo starinoslovca Simona Rutarja ter njegovo delovanje na Severnem Primorskem : diplomsko delo
Urban Makorič, 2021, diplomsko delo

Opis: Delo vključuje pregled življenja Simona Rutarja in poudarja ključne dogodke v njegovem življenju. Opisana je bila njegova kariera zgodovinarja, kjer so bile poudarjene njegove ključne objave. Fokus v opisu njegovega življenja so bile otroštvo, izobrazba in nesrečna ljubezen. V drugem delu diplomske naloge smo se posvetili arheologiji Severne Primorske. Pod drobnogled so prišla najdišča, ki jih je opisoval že Simon Rutar. Ta so Gradič, Robič, Tonovcov grad in Sveta Lucija. Pridružile so se jim analize rimskih cest ter grob oris poselitve območja za lažje razumevanje zgodovinskega konteksta.
Ključne besede: diplomske naloge, zgodovinopisje, slovenska zgodovina, arheologija, 19. stoletje, Severna Primorska, Kobarid, Zgornje Posočje, Robič, Gradič, Sveta Lucija, rimske ceste
Objavljeno v RUNG: 08.09.2021; Ogledov: 2386; Prenosov: 118
URL Povezava na celotno besedilo
Gradivo ima več datotek! Več...

9.
Raziskava organizacijske klime v izbrani organizaciji iz storitvene dejavnosti
Urban Černe, 2020, diplomsko delo

Opis: V teoretičnem delu pojasnjujemo pojem organizacijske klime in njene ključne dejavnike. Na podlagi štirinajstih dimenzij smo ugotavljali bistvena področja organizacijske klime. Vse dimenzije smo natančno preučili, jih opisali in kasneje analizirali s pomočjo pridobljenih podatkov. V empiričnem delu predstavljamo raziskavo, ki smo jo izvedli z anonimnim anketnim vprašalnikom na izbranem oddelku, rezultate smo prikazali grafično in predlagali ukrepe za odpravo neustreznih stanj organizacijske klime.
Ključne besede: organizacijska klima, zadovoljstvo, storitvena dejavnost, dimenzije organizacijske klime, raziskava, izbrana organizacija
Objavljeno v RUNG: 03.07.2020; Ogledov: 3034; Prenosov: 94
.pdf Celotno besedilo (1,33 MB)

10.
Facilitating green care improvements in viticulture
Melita Sternad Lemut, Lorena Butinar, Adesida Rowland, Urban Česnik, Tjaša Jug, Paolo Sivilotti, Urška Vrhovšek, 2019, objavljeni znanstveni prispevek na konferenci

Opis: The growing demand of consumers for environment-friendly and safe food products already forced many winemakers to restrict the application of synthetic fungicides to earlier season, trying to reduce the risk of residues being detected in wines. Main risk for infection by B. cinerea, however, occurs later in the season. To support an improvement in whole-season B. cinerea green care, the potential of yeasts as biocontrol agent (PBA) was studied. Selected yeasts were tested for their antifungal activities. Furthermore, a field experiment in Pinot noir and Pinot gris vineyards was designed to study different combinations of optimized canopy microclimate manipulation (CMM) techniques and PBA application. In experimental conditions, PBA's ability to maintain appropriate population density for disease prevention was observed. Grape and wine quality parameters were evaluated. Analytical approach of metabolomics was applied to upgrade the understanding of potentially induced changes in plant metabolism. Based on yeasts testing results, biocontrol yeast P. guilliermondii ZIM 624 was selected and after its field application, we were able to detect its suitable density on grapes until harvest. In case of early defoliation for both varieties smaller grape compactness was confirmed together with lower yield. Among grape basic quality parameters, optimized techniques showed positive effect on sugar content, but unexpectedly, in the treatments with biocontrol yeasts the trends toward higher acidity were noticed in Pinot gris. CMM and PBA introduction indicated some effects on grapevine biosynthetic behaviour but the differences in content of these metabolites compared to control were poorly detected in final wines with exception of mainly some flavonols, stilbenes and flavan-3-ols (and consequently total phenolic content).
Ključne besede: sustainable viticulture, Botrytis cinerea, yeasts, biocontrol, canopy microclimate manipulation, metabolomics, grapevine metabolites
Objavljeno v RUNG: 28.02.2020; Ogledov: 3677; Prenosov: 0
Gradivo ima več datotek! Več...

Iskanje izvedeno v 0.06 sek.
Na vrh