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11.
Polifenolni profil grozdja sorte 'Refošk' (Vitis vinifera) letnika 2011 na Krasu
Borut Hrovatin, 2014, diplomsko delo

Najdeno v: osebi
Ključne besede: diplomske naloge, Refošk, Kras, antocianini, HPLC, spektrofotometer
Objavljeno: 25.04.2014; Ogledov: 3110; Prenosov: 160
URL Polno besedilo (0,00 KB)
Gradivo ima več datotek! Več...

12.
Olive fruit phenols in olive oil processing
Tina Jerman, 2014, doktorska disertacija

Najdeno v: osebi
Ključne besede: oljčno olje, proizvodnja, fenoli, odpadni produkti, analize, Istrska belica cv., malaksacija, čas, temperatura, tlak, disertacije
Objavljeno: 22.01.2015; Ogledov: 2389; Prenosov: 51
URL Polno besedilo (0,00 KB)
Gradivo ima več datotek! Več...

13.
Determination of polyphenols in white grape berries cv. Rebula
Polonca Trebše, Branka Mozetič Vodopivec, Irma Tomažič, Andreja Škvarč, 2006, izvirni znanstveni članek

Najdeno v: osebi
Ključne besede: belo grozdje, HPLC-DAD, MS/MS, hidroksicimetne kisline
Objavljeno: 10.07.2015; Ogledov: 2201; Prenosov: 13
URL Polno besedilo (0,00 KB)

14.
Identification of sweet cherry anthocyanins and hydroxycinnamic acids using HPLC coupled with DAD and MS detector
Polonca Trebše, Branka Mozetič Vodopivec, 2004, izvirni znanstveni članek

Opis: In absence of standards, HPLC coupled with DAD offers identification of polyphenols by scanning UV-Vis spectra of individual components, which spectral characteristics are unique, but not selective. At the same time HPLC-DAD determination methods of polyphenols differ in mobile phase solutions resulting in DAD scanned spectra deviation between different studies, aggravating the precise identification based on agreement to UV-Vis data from literature. Mass spectrometry (MS) detection with molar weight determination of the individual components in the sample enables more precise identification of compounds eluted from the column. Sweet cherry Petrovka polyphenols were separated on C18 Hypersil PEP 300 column (250 x 4.6 mm, 5 [mu]m) using gradient solvent mixture consisting of methanol, water and formic acid. MS and UV-Vis spectra of eluted anthocyanins and hydroxycinnamic acid were recorded. HPLC-MS analyses were performed using a LCQ [sup]TM ion trap, Finnigan, MAT mass spectrometer by atmospheric pressure chemical ionisation (ACPI). Molecular and fragmented ion masses of sweet cherry hydroxycinnamic acids and anthocyanins were determined and with UV-Vis spectra, in the range of 190-600 nm, used for identification of compounds. Electro spray mass spectrum of two hydroxycinnamic acids produced ions with m/z ratios of 353.0 and 337.0, which corresponded to molecular weights of neochlorogenic acid and 3'-p-coumarylquinic acid. The molecular weights of 5 anthocyanins corresponded to cyanidin-3-glucoside (449.0), cyanidin-3-rutinoside (595.1), peonidin-3-glucoside (463.1), pelargonidin-3-rutinoside (579.1) and peonidin-3-rlltinoside (609.2).
Najdeno v: osebi
Ključne besede: češnje, antociani, hidroksicimetne kisline, HPLC-DAD/MS
Objavljeno: 10.07.2015; Ogledov: 2323; Prenosov: 6
URL Polno besedilo (0,00 KB)

15.
EFFECT OF TIMING OF LEAF REMOVAL ON YIELD PARAMETERS, GRAPE AND WINE QUALITY OF VITIS VINIFERA L. CV. 'SAUVIGNON BLANC' Daniela MARKOVIC
Daniela Markovic, 2016, diplomsko delo

Opis: Z odstranjevanjem listov v predelu grozdov se lahko spremeni mikroklima grozdov, ki lahko izzove spremembe v sekundarnem metabolizmu vinske trte, ki so odvisne tudi od časa izvedbe ukrepa. Uravnavanje sinteze aromatskih komponent je zanimivo pri belih sortah kot je sorta 'Sauvignon blanc', kjer so metoksipirazini in tioli tisti, ki oblikujejo značilno aromo vina te sorte. Eksperiment diplomske naloge smo zastavili na Oslavju (Gorica, Italija) v vinogradu sorte grozdja 'Sauvignon blanc' (Vitis vinifera L.). Želeli smo preveriti vpliva odstranjevanja listov v predelu grozdja pred in po cvetenju na količino in kakovost pridelka ter aromatske lastnosti grozdja in vina. Količinski parametri pridelka so pokazali majhne vplive izvedenih ukrepov razlistanja; pozno razlistanje na količino pridelka ni vplivalo, v nasprotju z razlistanjem pred cvetenjem, kjer smo opazili rahlo zmanjšanje pridelka po trsu in mase grozdov. Tudi pri osnovnih zrelostnih parametrih smo opazili manjše spremembe, predvsem večje vsebnosti topne suhe snovi pri razlistanju pred cvetenjem. Pri aromatskih komponentah smo zaznali vpliv razlistanja pred cvetenjem na količino prekurzorjev tiolov tako v grozdju kot tudi vinu; večjo vsebnost 4-merkapto-4-metilpentan-2-on (4MMP) in nižje koncentracije 3-merkaptoheksan-1-ol (3MH). S poznejšim odstranjevanjem listov smo zmanjšali koncentracije 4MMP, na vsebnost 3MH ta ukrep ni vplival. Tudi s senzorično oceno vina smo potrdili pomembne vplive razlistanja pred in po cvetenju na določene note v aromi vina 'Sauvignon blanc'. Leaf removal changes cluster microclimate, and thus modifications in the secondary metabolism are triggered, but differently as regard to the timing of application. In case of white grape varieties, the interest on the modification of aroma characteristics is searched, and in case of 'Sauvignon blanc', the shift in concentration of methoxypyrazines and thiols is responsible for the bouquet of the wines. An experimental trial was set up in Oslavia (Gorizia, Italy) with the aim to evaluate how pre-flowering and post-flowering leaf removal applied on 'Sauvignon blanc' vines could change the aromatic occurrence in grapes and wines. The yield parameters were slightly affected by the treatments of leaf removal; while late leaf removal did not impact on production, pre-flowering leaf removal slightly promoted a reduction on yield and cluster weight. Also basic maturation parameters were slightly changed, mainly higher soluble solids in case of pre-flowering leaf removal. As regard aromatics, both thiol precursors in grapes and thiols in wines revealed to be shifted in case of pre-flowering leaf removal, with higher values of 4-mercapto-4-methyl-pentan-2-one and lower values of 3-mercaptohexan-1-ol. In case of late leaf removal lower concentration of 4MMP were revealed and similar of 3MH. Also the degustation of the wines revealed some peculiarities of pre-flowering and late leaf removal treatments for some important sensorial notes of 'Sauvignon blanc' wines.
Najdeno v: osebi
Ključne besede: Vitis vinifera L. cv. 'Sauvignon blanc', razlistanje pred cvetenjem, razlistanje po cvetenju, aromatske komponente, tioli, LC-MS Vitis vinifera L. cv. 'Sauvignon blanc', pre-flowering leaf removal, post-flowering leaf removal, aromatic compounds, thiols, LC-MS
Objavljeno: 14.01.2016; Ogledov: 2963; Prenosov: 178
.pdf Polno besedilo (1,30 MB)

16.
Isotopic and elemental characterisation of Slovenian apple juice according to geographical origin: Preliminary results
Nives Ogrinc, Peter Kump, Ines Mulič, Branka Mozetič Vodopivec, Darja Mazej, Klemen Eler, Karmen Bizjak Bat, 2016, izvirni znanstveni članek

Opis: This study examined the applicability of stable isotope and multi-element data for determining the geographical origin of fresh apple juices. Samples included three apple cultivars (Idared, Golden Delicious and Topaz) harvested in 2011 and 2012 from five different geographical regions of Slovenia. Regional discrimination of the juice samples was most successful when using linear discriminant analysis (LDA) and taking into account the following parameters: d2H and d18O content of juice water; d15N and d13C content of the pulp, (D/H)I and (D/H)II in ethanol and the concentration of S, Cl, Fe, Cu, Zn and Sr. Overall prediction ability was 83.9%. The factors that best distinguished the different types of cultivar were the d2H and d18O content of fruit juice water; the d13C and (D/H)I content of ethanol; and the concentration of S, Mg, K, Cu, and Ti. Prediction ability, taking into account all ten parameters, was 75.8%.
Najdeno v: osebi
Ključne besede: Apple juice, Stable isotopes, Elemental content, Geographical origin, Slovenia
Objavljeno: 15.02.2016; Ogledov: 2136; Prenosov: 0
.pdf Polno besedilo (892,49 KB)

17.
CHARACTERIZATION OF SLOVENIAN APPLE JUICE WITH RESPECT TO ITS GEOGRAPHICAL ORIGIN AND AGRICULTURAL PRODUCTION PRACTICE
Karmen Bizjak Bat, 2016, doktorska disertacija

Opis: Determination of food authenticity is an important issue in quality control and food safety. Recent studies predict a growing demand for natural and more authentic food and beverage products. The quality and authenticity of apple juice is also of a great economic importance since the popularity and demand for apple juice consumption has increased. The growth of the market for organically produced apples and apple juice is due to the increasing demand for healthy food requirements, protection of the environment and the promotion of biotic diversity. Organic foods have a higher nutritional and health value, but they are more expensive, because their production is more difficult and less profitable. In addition to how food is produced, consumers are increasingly placing emphasis on food products of specific region, which are known for their unique natural flavours and taste. The presented thesis is based on four separate but closely interrelated studies, in which a combination of different isotopic ratios of bioelements (2H/1H, 13C/12C, 15N/14N, 18O/16O), multi-element analysis, and major primary and secondary metabolite profiles were exploited to differentiate the geographical origin and agricultural production practice (organic vs integrated/conventional) of Slovenian apples. These parameters were used to establish the first database of authentic Slovenian apple juice, which can be used to verify the authenticity of commercially available apple juice in Slovenia. The first preliminary study was entitled “Organic Cultivation ~ Geographical Origin (OCGO)” and was performed using apples from the 2009 growing season. Its aim was to examine the use of stable isotope and multi-element data for determining the geographical origin and agricultural production practice of fresh apple juices. Fruits of six apple (Malus domestica Borkh) cultivars (Topaz, Idared, Golden Delicious, Goldrush, Gala, Gloster) were collected from four different geographical regions of Slovenia (Alpine, Dinaric, Pannonian and Mediterranean) grown under organic and integrated/conventional orchard management systems. The results revealed that stable isotope parameters in sugar, pulp and water were the most significant variables for differentiating between the regions. Good separation was achieved between the geographical regions in Slovenia based on the δ18O and δ2H values in water and Rb and S levels in the apple fruit juice. The most significant variables that distinguished between organically and integrated/conventionally cultivated apples were the 15N/14N ratio and antioxidant activity of the apple juice. Significant differences were also observed in the ascorbic acid content of the juice. Based on these results the number and types of apples and the minimum number of samples needed from the same region for determining geographical origin were determined. The second study was called “Organic ~ Conventional Apple Cultivation” (OCAC) and was performed in 2010 and 2011 in a Gala apple orchard. The aim was to determine the effect of different fertilizers allowed either in organic or conventional/integrated agricultural regimes on different parameters. Quality parameters, isotopic composition of C in sugars and in pulp together with N and elemental analysis were investigated. The following five fertilizers were applied: Biosol and Plantella organic (organic) and Ca cyanamide, KAN and UREA (mineral) at a rate of 60 and 120 kg of nitrogen per hectare. From the obtained data it was possible to differentiate between organic and integrated/conventional apple production when taking into account the following parameters: mass, skin and flesh firmness (SFF), total soluble solids (TSS), and the content of Cl as well as δ15N and δ13C in the pulp. The “Organic Cultivation ~ Geographical Origin” (OCGO) study, which took place during the 2011 and 2012 growing seasons included a greater number of samples and samples from five different geographical regions: Alpine, Dinaric,
Najdeno v: osebi
Ključne besede: apple juice, geographical origin, agricultural production practice, biomarkers, phenol compounds, elements, stable isotopes, Slovenia
Objavljeno: 07.06.2016; Ogledov: 3222; Prenosov: 341
.pdf Polno besedilo (3,97 MB)

18.
Polyphenol, antioxidant and antimicrobial potential of six different white and red wine grape processing leftovers
Peter Raspor, Sonja Smole Možina, Katja Jug, Melita Sternad Lemut, Branka Mozetič Vodopivec, Anja Klančnik, Kajetan Trošt, 2016, izvirni znanstveni članek

Opis: BACKGROUND During winemaking, grape polyphenols are only partly extracted, and consequently unexploited. The main aim was to characterise the phenolic content of freeze-dried grape skin and seed (FDSS) extracts obtained from Slovenian and international grape varieties and evaluate their antioxidant, antimicrobial, and anti-adhesive activities. RESULTS FDSS of six Vitis vinifera L. grapevine cultivars from Vipava Valley region (Slovenia) underwent extraction and sonification under different conditions. Flavonols were the predominant content of extracts from white ‘Zelen’ and ‘Sauvignon Blanc’ grape varieties, with strong antimicrobial activities against Gram-negative bacteria. ‘Pinot Noir’ FDSS extracted with 50% aqueous ethanol extraction produced a high phenolic content in the final extract, which was further associated with strong antioxidant and antimicrobial activities against all tested bacteria. Bacterial adhesion to stainless steel surfaces with minimal and maximal surface roughness was significantly inhibited (up to 60%) across a wide FDSS concentration range, with lower concentrations also effective with two types of stainless steel surfaces. CONCLUSION FDSS extracts from winery by-products show interesting phenolic profiles that include flavonols, catechins, anthocyanins, and hydroxycinnamic acids, with yields influenced by grapevine cultivar and extraction conditions. The antioxidant, antimicrobial and anti-adhesive activities of 50% aqueous ethanol ‘Pinot Noir’ FDSS extract reveals potential applications in food, pharmaceutical and cosmetic industries for these bioactive residues.
Najdeno v: osebi
Ključne besede: grape skins and seeds, extraction solvents, phenolic profile, antioxidant activity, antimicrobial activity, anti-adhesion activity to stainless steel
Objavljeno: 08.08.2016; Ogledov: 1793; Prenosov: 0
.pdf Polno besedilo (2,02 MB)

19.
Vpliv različnih bentonitov na senzorične in kemijske lastnosti vina sorte 'Rebula' (Vitis vinifera L.)
Uroš Špacapan, 2018, diplomsko delo

Opis: Pomemben dejavnik pri kakovosti vina ter posledično tudi pri uspešni prodaji je stabilnost vina v steklenici, kajti v nasprotnem primeru pride do slabega ugleda vinarja in tudi zavračanja proizvoda na trgu. Beljakovinsko stabilnost vina lahko dosežemo na več načinov, ki pa so odvisni od same tehnologije in tudi trendov na vinskem trgu. V sklopu diplomske naloge smo preučevali vpliv uporabe štirih različnih bentonitov na kemijske in senzorične lastnosti vina sorte Rebula. Vino smo pred stekleničenjem tretirali z različnimi komercialno dostopnimi bentoniti in stekleničena vina kemijsko ter senzorično ovrednotili. Poleg določanja osnovnih kemijskih parametrov smo spektrofotometrično določili vsebnost skupnih fenolov in barve vina. S pomočjo encimskih kitov smo določili tudi vsebnost vinske, jabolčne in mlečne kisline v stekleničenih vinih. Rezultati našega poskusa kažejo, da je uporaba različnih bentonitov vplivala tako na kemijske kot tudi na senzorične lastnosti vina. V vinih tretiranih z bentonitom smo zaznali rahel trend nižjih vsebnosti alkohola ter skupnih titrabilnih in hlapnih kislin. Obenem pa smo zaznali tudi trende povečanja parametrov, kot je barva vina (absorbanca pri 420 nm) in vsebnosti skupnih fenolov primerjavi s kontrolnim – netretiranim vzorcem. Senzorična ocena tretiranih vin je nakazala trend siromašenja sadnih not pri vseh uporabljenih bentonitih, v določenih primerih pa, nasprotno, pozitivne vplive na zaznane cvetlične in rastlinske note. Rezultati so tako pokazali, da vrsta bentonita različno vpliva na senzorične lastnosti vina Rebula.
Najdeno v: osebi
Ključne besede: vino Rebula, belo vino, bentonit, kemijski parametri vina, senzorične lastnosti vina
Objavljeno: 13.02.2018; Ogledov: 1096; Prenosov: 94
.pdf Polno besedilo (1,62 MB)

20.
PRIPRAVA IN SENZORIČNA OCENA AROMATIZIRANEGA VINJAKA
Tina Žorž, 2018, diplomsko delo

Opis: V diplomskem delu smo obravnavali vpliv dodane naravne arome karamela na senzorične lastnosti vinjaka. V staran vinjak smo dodali 3 različne koncentracije naravne arome karamela, ki smo jo dobili na trgu v prosti prodaji. Aroma je namenjena tako živilskim kot tudi farmacevtskim izdelkom in vsebuje naravne komponente arome karamela. Senzorično oceno smo izvedli s pomočjo uradnega panela Kmetijsko gozdarskega zavoda Nova Gorica in ocenjevalnega lista, ki smo ga povzeli iz literature. V okviru senzorične ocene je ocenjevalna komisija pripravljene vzorce ocenjevala z opisno analizo in kvalifikacijsko analizo. Med potrošniki pa smo izvedli tudi test všečnosti. Rezultati diplomske naloge nakazujejo, da dodatek izbrane naravne arome karamela vinjaku v najnižji koncentraciji (5 ml/l), ki smo ga uporabili v diplomski nalogi, najbolje pripomore k boljši aromatiki in zaokroženemu okusu. Opazili smo, da dodatek arome v vinjak navkljub odsotnosti sladkorja pripomore k večji zaznavi sladkosti v okusu in k zakrivanju zaznavanja alkohola, kar je najverjetneje botrovalo preferenčnim razlikam med moškim in ženskim okusom do izbranih alkoholnih pijač. Ženske in mlajše generacije so se na splošno odločale za bolj aromatizirane vzorce, moške pa sta bolj prepričala osnovni vzorec in vzorec z majhnim dodatkom karamele.
Najdeno v: osebi
Ključne besede: vinjak, aroma karamele, senzorična ocena, analiza potrošnikov
Objavljeno: 30.07.2018; Ogledov: 1247; Prenosov: 74
.pdf Polno besedilo (1,97 MB)

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