51. EFFECT OF TIMING OF LEAF REMOVAL ON YIELD PARAMETERS, GRAPE AND WINE QUALITY OF VITIS VINIFERA L. CV. 'SAUVIGNON BLANC' Daniela MARKOVICDaniela 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.
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 v RUNG: 14.01.2016; Ogledov: 9045; Prenosov: 308
 Celotno besedilo (1,30 MB) |
52. Identification of sweet cherry anthocyanins and hydroxycinnamic acids using HPLC coupled with DAD and MS detectorPolonca 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).
Ključne besede: češnje, antociani, hidroksicimetne kisline, HPLC-DAD/MS
Objavljeno v RUNG: 10.07.2015; Ogledov: 6852; Prenosov: 24
 Povezava na celotno besedilo |
53. |
54. Olive fruit phenols in olive oil processing : the fate and antioxidant potentialTina Jerman, 2014, doktorska disertacija Ključne besede: oljčno olje, proizvodnja, fenoli, odpadni produkti, analize, Istrska belica cv., malaksacija, čas, temperatura, tlak, disertacije
Objavljeno v RUNG: 22.01.2015; Ogledov: 7211; Prenosov: 308
Povezava na celotno besedilo
Gradivo ima več datotek! Več... |
55. |
56. |
57. |
58. |
59. |
