• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 155
  • 100
  • 48
  • 38
  • 31
  • 7
  • 6
  • 5
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 415
  • 415
  • 142
  • 140
  • 86
  • 72
  • 69
  • 61
  • 51
  • 51
  • 46
  • 44
  • 42
  • 41
  • 38
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Expression and purification of recombinant extracellular proteases originating from non-Saccharomyces yeasts

Theron, Louwrens Wiid 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: During wine fermentation, yeasts release extracellular enzymes that significantly impact wine properties. While the extracellular proteins of Saccharomyces cerevisiae have been characterised, those of non-Saccharomyces yeasts remain largely unknown. Most of these enzymes break down sugar polymers or catalyse the liberation of glycosidically-bound molecules. Another category of enzymes of oenological interest is represented by acid proteases that are able to prevent or reduce protein haze, as reported in literature, while simultaneously increasing the assimilable nitrogen content of wine. The liberation of amino acids from peptides and proteins that serve as aroma precursors may also have an indirect effect on wine aroma. In a recent study performed at the Institute for Wine Biotechnology (IWBT), the sequences of two aspartic proteases were retrieved from non-Saccharomyces yeast species isolated from South African wines. The genes, MpAPr1 and CaAPr1, were isolated from two non-Saccharomyces species, Metschnikowia pulcherrima IWBT Y1123 and Candida apicola IWBT Y1384, respectively. However, no further characterization was undertaken. This study aimed to clone these two genes into a recombinant bacterial host for expression and purify the corresponding enzymes as a first step toward characterizing their kinetic properties. Considering that some non-Saccharomyces species have been shown to produce more than one acid protease, an additional aim was to identify novel acid proteases within M. pulcherrima IWBT Y1123. Cloning of the genes and transformation of the expression vectors into E. coli were achieved. Optimal conditions for induced expression were established following extensive optimization. Furthermore, while native extraction of the recombinant proteins was unsuccessful, denaturing conditions allowed their recovery, suggesting that the recombinant proteins are encapsulated into inclusion bodies. Recombinant MpAPr1 was purified by using a nickel based column system and mass fingerprinting of the purified enzyme (MpAPr1) confirmed its identity. Purification was followed by refolding experiments, but yielded poor recovery of active enzymes. Unfortunately, recombinant expression of CaAPr1 could not be observed for reasons yet to be elucidated that may include the large sequence dissimilarities between CaAPr1 and MpAPr1. Finally, Southern blot analysis on the genomes of M. pulcherrima IWBT Y1123 and C. apicola IWBT Y1384 revealed that both possess at least one additional protease other than those previously described. Further analysis of the extracellular proteome of M. pulcherrima IWBT Y1123 also confirmed the presence of at least one enzyme able to hydrolyze BSA at a low pH. Unfortunately, mass fingerprinting performed on the entire extracellular proteome and on small groups of proteins thereof did not allow the identification of these enzymes. / AFRIKAANSE OPSOMMING: Gedurende fermentasie van druiwe sap skei gis ekstrasellulêre ensieme af wat ‘n aanmerklike impak op wyn eienskappe het. Terwyl die ekstrasellulêre proteïene vanaf Saccharomyces cerevisiae al gekarakteriseer is, bly die van nie-Saccharomyces spesies grootliks onbekend. Meeste van hierdie ensieme breek suiker polimere af of kataliseer die vrystelling van glikosiediese verbonde molekules. ‘n Ander klas van ensieme wat van belang is vir oenologie word voorgestel deur proteases wat in staat is daartoe om proteïenewaas te verminder, soos voorheen geraporteer is in literatuur, terwyl dit terselfde tyd die assimileerbare stikstof inhoud kan vermeerder. Die vrystelling van aminosure vanaf peptiede en/of proteïene wat as aroma voorlopers dien mag ook ‘n indirekte effek op die wyn se aroma profiel hê. In ‘n onlangse studie wat uitgevoer is by die Instituut vir Wynbiotegnologie (IWBT) was die volgordes van twee aspartiese proteases bepaal vanaf twee nie-Saccharomyces gis spesies wat geisoleer was uit Suid-Afrikaanse wyne. Die gene MpAPr1 en CaAPr1, was afsonderlik geisoleer vanuit twee nie- Saccharomyces giste, Metschnikowia pulcherrima IWBT Y1123 en Candida apicola IWBT Y1384. Egter was daar geen verder karakterisering van hierdie ensieme nie. Die doel van hierdie studie is om die bogenoemde gene in ‘n rekombinante bakteriese gasheer te kloneer vir uitdrukking en suiwering as ‘n eerste stap tot karakterisering van hul kinetiese eienskappe. Om in ag te neem dat sommige nie-Saccharomyces spesies meer as een protease produseer was ‘n aditionele mikpunt om vir nuwe suur proteases te soek binne M. pulcherrima IWBT Y1123. Klonering van hierdie gene en transformasie van die uitdrukkings vektore in E. coli was suksesvol. Optimale kondisies vir die induksie van ekspressie was bevestig na omvattende optimalisering. Verder, terwyl inheemse ekstraksie van die rekombinante proteïene onsuksesvol was, het denatureerende kondisies toegelaat vir suksesvolle ekstraksie, wat voorgestel het dat die rekombinante proteïene geinkapsileer word in inklusie liggame. Rekombinante MpAPr1 was gesuiwer deur gebruik te maak van ‘n niekel gebaseerde kolom sisteem en massa petied fingerafdrukke van die gesuiwerde ensiem (MpAPr1) het die identiteit bevestig. Suiwering was gevolg deur hervouing eksperimente, maar het swak opbrengste gelewer van die aktiewe ensiem. Ongelukkig kon die rekombinante ekspressie van CaAPr1 nie gevisualiseer word nie vir redes wat nog bevestig moet word, maar wat mag behels dat daar groot volgorde veskille tussen MpAPr1 en CaAPr1 kan wees. Uiteindelik was Southern blot hibridiseering analises uitgevoer op die genome van albei M. pulcherrima IWBT Y1123 en C. apicola IWBT Y1384 wat voorgestel het dat albei ten minste een addisionele protease, anders as die wat voorheen geidentifiseer was, bevat. Verder analiese van die ekstrasellulêre proteoom van M. pulcherrima IWBT Y1123 het ook die teenwoordigheid van ten minste een ensiem bevestig wat die vermoë het om BSA te hidroliseer by ‘n lae pH. Ongelukkig het massa peptied vingerafdrukbepaling wat uitgevoer was op die hele ekstrasellulêre proteoom en op klein groepe protein nie identifikasie van hierdie ensieme bevestig nie.
282

Evaluating the impact of yeast co-inoculation on individual yeast metabolism and wine composition

Mains, Arlene Olive 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The use of non-Saccharomyces yeasts together with Saccharomyces cerevisiae in mixed starter cultures has become an accepted oenological tool to enhance the organoleptic properties of wine. Recent studies have indeed demonstrated the positive contribution that non- Saccharomyces yeasts may have on the bouquet of wine. These mixed starter cultures are characterized by high inoculation levels of individual strains into the must, and each strain in turn is characterized by its own specific metabolic activity. These factors lead to a multitude of interactions occurring between the individual populations within the must. The fundamental mechanisms which drive these interactions are still largely unknown, but several studies have been conducted in order to investigate the metabolic outcome of these interactions. In this study, we endeavour to further characterize the interactions which occur between four individual non-Saccharomyces yeast strains in mixed culture fermentation with S. cerevisiae. Metschnikowia pulcherrima IWBT Y1337, Lachancea thermotolerans IWBT Y1240, Issatchenkia orientalis Y1161 and Torulaspora delbrueckii CRBO LO544 were used in mixed culture fermentations with a commercial strain of S. cerevisiae at an inoculation ratio of 10:1 (non-Saccharomyces: S. cerevisiae). The biomass evolution and fermentation kinetics of both participating species were affected by the high cell density of the other, with neither population reaching the maximal density attained by the pure culture fermentation. The final wine composition of each individual mixed fermentation showed clear differences, from the pure cultured S. cerevisiae and from each other, based on the concentrations of the major volatile compounds found in the wine. Upon further characterization of these specific mixed culture fermentations, it was found that each individual combination of non-Saccharomyces and S. cerevisiae produced similar increases and decreases of certain major volatile compounds as demonstrated by previous authors, using the same combination of non-Saccharomyces species together with S. cerevisiae. From a winemaking perspective, the use of these non- Saccharomyces yeast strains in combination with S. cerevisiae could be a useful strategy to diversify the chemical composition of wine, by increasing the concentration of certain desirable volatile compounds and by modulating the concentration of undesirable metabolites. Furthermore, this research serves as a foundation for further elucidation of the interactions which drive these metabolic outcomes in response to the high cell density of two yeast populations in mixed culture fermentations.
283

The evaluation of Fourier transform infrared (FT-IR) spectroscopy and multivariate data analysis techniques for quality control at aniIndustrial cellar

Hoon, Ansunette 04 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The alcoholic beverage industry needs objective analysis of grape juice and liqueur quality. Fourier transform infrared (FT-IR) spectroscopy with multivariate data analysis techniques is widely used in wine laboratories across South Africa for accurate, fast and high sample throughput analyses. In this study the potential of FT-IR spectroscopy is evaluated for the quantification of ammonia in freshly pressed grape juice. FT-IR spectroscopy is evaluated, using two different spectrometers, in respectively attenuated total reflection (ATR) - and transmission scanning modes for the quantification of alcohol, pH and invert sugar in spirit-based liqueurs. The ultimate aim was to implement the PLS regression algorithms developed at an industrial cellar and replace the complex and lengthy reference methods used at the time of this study. Principle component analysis (PCA) was performed prior to the calibration step to identify groupings and patterns within the spectra. The PLS calibration models were developed from samples collected at the cellar and using partial least square (PLS) regression. The models were evaluated using the performance criteria coefficient of determination (R2) and root mean squared error of cross validation (RMSECV) at calibration stage, and root mean square error of prediction (RMSEP) and residual predictive deviation ratio (RPD) at validation stage. The average RMSEP (1.88 mg/L) of the ammonia PLS calibration model was in agreement with the standard error of laboratory (SEL = 1.54 mg/L). The R2 (92.05) and average RPD (3.3) proposed a model with excellent precision for screening purposes that was ready to be transferred for use by the laboratory. The r2 values for the alcohol, pH and invert sugar PLS calibration models obtained in ATR and transmission, indicated good to excellent precision (80<r2<100). The alcohol PLS calibration model obtained in transmission was suitable for quality- and process control purposes (RPD = 21.2), while the invert sugar PLS calibration model for quality control purposes (5<RPD<6.4). The pH and invert sugar calibration models obtained in ATR were suitable for screening purposes with RPD = 3.6 and RPD = 4.8, respectively. These PLS regression algorithms were implemented at the cellar. The pH PLS calibration model obtained in transmission was suitable for rough screening of samples (RPD = 2.7) and future development was neccesary to increase the predictability of the model. The results obtained in this study made a significant contribution towards validation of FT-MIR as a powerful tool for rapid quantification of quality indicating parameters in wine and spirit-based liqueurs. The contribution is particularly valuable in the context of ongoing research to improve the quality of products at the cellar to meet consumer demands. The knowledge gained on quantification of quality indication parameters of spirit-based liqueurs is novel and this is one of the first reports on implementation of mid-infrared (MIR) spectroscopy for the quality control of South African spirit-based liqueurs. / AFRIKAANSE OPSOMMING: Die wynindustrie benodig objektiewe analises van druiwesap- en likeurgehalte. Fourier-transformasie- infrarooi (FT-IR) spektroskopie met multiveranderlike statistiese metodes word gebruik in wynlaboratoriums regoor Suid-Afrika vir akkurate, vinnige en hoë monsterdeurset ontledings. In hierdie studie is die potensiaal van FT-IR spektroskopie geëvalueer vir die kwantifisering van ammoniak in die sap van vars geparste wyndruiwe. Twee verskillende FT-IR spektroskopie instrumente, in onderskeidelik (verswakte totale refleksie, ATR) - en transmissie skandering is gebruik vir die kwantifisering van alkohol, pH en invertsuiker in spiritus-gebaseerde likeurs. Die uiteindelike doel was om die parsiële kleinste kwadraat (PKK)- regressie algoritmes wat ontwikkel is, by 'n industriële kelder te implementeer en die komplekse en tydrowende verwysingmetodes wat tydens die studie in die kelder gebruik is te vervang. Verskeie multiveranderlike hoofkomponentanalise (MVK) is uitgevoer voor die kalibrasie stap, met die doel om groeperings en patrone in die spektra te identifiseer. Die PKK kalibrasiemodelle is ontwikkel van monsters wat by die kelder versamel is en die spektra is gebruik in die PKK regressies. Tydens die kalibrasiefase is die modelle geëvalueer met behulp van die bepalingskoëffisiënt (R2) en gemiddelde kalibrasieprediksiefout en tydens die validasiefase, met behulp van die standaardvoorspellingsfout (SVF) en relatiewe voorspellingsafwyking (RVA). Die gemiddelde SVF (1.88 mg/L) van die ammoniak kalibrasiemodel was in ooreenstemming met die standaard fout van die laboratorium (SEL = 1.54 mg/L). Die R2 (92.05) en die gemiddelde RVA (3.3) dui op ‘n model met uitstekende presiesheid wat gereed is vir oordra en gebruik deur die industrie. Die R2 waardes vir die alkohol-, pH- en invertsuiker –kalibrasie-modelle wat met ATR en transmissie vir die likeurmonsters ontwikkel is, dui op goeie tot uitstekende presiesheid (80<R2<100). Die alkoholkalibrasiemodel wat ontwikkel is in transmissie, is geskik vir kwaliteits- en prosesbeheerdoelwitte (RVA = 21.2), terwyl die invertsuiker kalibrasiemodel geskik is vir kwaliteitsbeheer doelwitte (5<RVA<6.4). Die pH en invertsuiker kalibrasiemodelle in ATR is geskik vir vinnige evalueringsdoelwitte, met RVA = 3.6 en RVA = 4.8 waardes, onderskeidelik. Hierdie algoritmes is ook in die kelder geimplementeer. Die pH kalibrasiemodel in transmissie was geskik vir vinnige evalueringsdoelwitte (RVA = 2.7) en toekomstige ontwikkeling is nodig om die voorspellingsakkuraatheidvan die model te verbeter. Die resultate van hierdie studie het ‘n betekenisvolle bydrae gelewer tot bevestiging van infrarooi spektroskopie as 'n kragtige tegnologie vir die vinnige kwantifisering van gehalteparameters in druiwesap en spiritus-gebaseerde likeurs. Die bydrae is veral waardevol in die konteks van voortgesette navorsing om die kwaliteit van produkte by die kelder te verbeter en aan verbruikerseise te voldoen. Die studie vir die kwantifisering van gehalteparameters in spiritus-gebaseerde likeurs is eerste in sy soort en een van die gerapporteerde verslae vir die implementering van infrarooi spektroskopie vir gehaltebeheer van Suid-Afrikaanse spiritus-gebaseerde likeurs.
284

Influence of winemaking practices on the chemical characteristics of winery wastewater and the water usages of wineries.

Conradie, Adel 04 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The production of wine globally has increased over the past years, increasing the volume of water used and wastewater generated for every litre of wine produced. In the past, the small volumes of winery wastewater that were produced by wineries had little effect on the immediate environment. However, with the increasing wine production all around the world, winery wastewater is a rising concern for the contamination of soil and subsurface flow. In order to fully understand the impacts of winery wastewater, it is important to establish the volumes and chemical characteristics of the wastewater, before considering possible treatments. The first aim of this study was to determine the influence of certain winemaking practices on the water usage. Two wineries in the Stellenbosch Winelands District were monitored during two harvests and one post-harvest season. It was evident through this study that water plays a vital role during the production of wine and that water is needed at virtually all the winemaking steps. However, the volume of clean water needed differs immensely during the course of the production process. It was noticed that throughout the harvest period at both wineries the clean water demand was highest and decreased during the course of the post-harvest period and steadily increased again towards the end of the year. The harvest period contributes between 30 and 40% of the yearly water usage at the respective wineries. It was also noticed that certain winemaking practices including filtering with a bulk filter, washing of barrels and bottling contributes heavily to the water usage throughout the year. Activities that increase water usage during harvest include the washing of the press and processing a combination of red and white grapes on the same day. Furthermore, it was identified that one of the wineries used a smaller volume of water on a daily basis and per tonnage during harvest than the other, indicating that the cleaner production strategy established 10 years earlier has a positive impact on their water usage. The second aim of this study was to monitor the raw and treated winery wastewater from the two wineries during a period of 15 months, including two harvests and one post-harvest season. This was done to investigate the characteristics of the raw and treated wastewater. Firstly, to determine the impact of the different winemaking practices on the chemical composition of the wastewater and secondly, to determine the efficiency of the existing constructed wetlands on the wastewater and the characteristics of the treated wastewater. From this study it was possible to make two main observations concerning the chemical oxygen demand (COD) concentrations of the two wineries. Primarily, it was observed there were variations in the raw wastewater characteristics of the two wineries and above all, that both wineries showed a decrease in the COD of the raw wastewater produced. Not only did the decrease in the raw wastewater COD over this period show promising results when a cleaner production plan is established and managed it also seems to show a decrease in the volumes of water used by the respective wineries and increase in quality. / AFRIKAANSE OPSOMMING: Gedurende die afgelope paar jaar het wynproduksie wêreldwyd toegeneem en as gevolg hiervan toenemende hoeveelhede water gebruik en afvalwater gegenereer. In die verlede het die klein volumes kelderafvalwater wat deur wynkelders geproduseer is min effek op die onmiddelike omgewing gehad, maar gegewe die toenemende produksie van wyn regoor die wêreld is daar groeiende kommer oor die besoedeling van gronde en ondergrondse vloei deur kelderafvalwater. Dit is belangrik om die volumes en chemiese eienskappe van die afvalwater te bepaal om die impak van die water ten volle te verstaan, voordat moontlike behandelings oorweeg word Die eerste doel van hierdie studie was om te bepaal hoe sekere wynmaakpraktyke watergebruik beïnvloed. Twee wynkelders in die Stellenbosch Wynland Distrik is gedurende twee parsseisoene en een na-pars seisoen gemonitor. Hierdeur het dit duidelik geword dat water ‘n noodsaaklike rol speel in wynproduksie en benodig word vir feitlik alle stappe in die wynmaakproses. Die volume skoon water wat benodig word verskil wel noemenswaardig tydens die produksieproses. Die gebruik van skoon water van beide kelders was hoog tydens die parsseisoen, het afgeneem gedurende die loop van die na-pars periode en het geleidelik weer toegeneem teen die einde van die jaar. Die parsseisoen dra tussen 30 en 40% by tot die jaarlikse waterverbruik van die onderskeie kelders. Dit is ook opgemerk dat sekere wynmaakpraktyke, insluitend filtrasie met ‘n grootmaat filter, die was van vate en bottelering, grootliks bydrae tot die waterverbruik deur die loop van die jaar. Aktiwiteite wat waterverbruik tydens parstyd verhoog sluit in die gebruik van die pers en die verwerking van ‘n kombinasie van rooi en wit druiwe op dieselfde dag. Daar is ook vasgestel dat een van die wynkelders tydens parstyd ‘n kleiner volume water gebruik op ‘n daaglikse basis asook per tonnemaat wat daarop dui dat die “skoner” produksie strategie wat dié kelder 10 jaar gelede gevestig het wel ‘n positiewe impak op waterverbruik het. Die tweede doel van hierdie studie was om die onbehandelde en behandelde afvalwater van hierdie twee wynkelders te monitor oor 'n tydperk van 15 maande, wat twee paste en een na-pars seisoen insluit. Dit is gedoen om die impak van verskillende wynmaakpraktyke op die chemiese samestelling van die afvalwater te ondersoek asook om die doeltreffendheid van bestaande kunsmatige vleilande in terme van afvalwaterbehandeling te bepaal en die eienskappe van die behandelde afvalwater te ondersoek. Gevolglik is twee belangrike waarnemings oor die chemiese suurstof behoefte (CSB) konsentrasie van die twee wynkelders gemaak. Variasies in die onbehandelde afvalwater eienskappe is waargeneem by beide wynkelders en daar was ‘n afname in CSB van die onbehandelde afvalwater by beide wynkelders. Die afname in CSB van die onbehandelde afvalwater oor hierdie tydperk is belowend en dit blyk dat wanneer ‘n “skoner” produksie plan opgestel en bestuur word dit wel ‘n afname in waterverbruik en verhoog in kwaliteit by die kelders tot gevolg het.
285

Análise isotópica do gás carbônico de espumantes comercializados no Brasil / Isotopic analysis of sparkling wines sold in Brazil

Jubileu, Bruno da Silva [UNESP] 25 May 2015 (has links) (PDF)
Made available in DSpace on 2016-03-07T19:21:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-05-25. Added 1 bitstream(s) on 2016-03-07T19:25:29Z : No. of bitstreams: 1 000858832.pdf: 994543 bytes, checksum: 2432f925f648e3fe972141c68c3b2506 (MD5) / O objetivo deste trabalho foi analisar isotopicamente o gás carbônico de espumantes para detectar adulteração, utilizando o método de análise isotópica para determinar a origem deste gás; se proveniente de plantas dos ciclos fotossintéticos C3 (uva), C4 (açúcar de cana) ou de outra fonte. Para isso, foram analisadas amostras comerciais de espumante e espumante moscatel, espumantes elaborados em laboratório, sumo de uva, açúcar e gás carbônico comercial. Também foram analisadas outras bebidas carbonatadas (água mineral, refrigerantes, vinhos, etc.). Os resultados foram submetidos à análise de variância e teste de Tukey para a detecção de possíveis diferenças entre as médias das razões isotópicas de 13C/12C, ao nível de significância de p <0,05. Seguindo a legislação brasileira para vinhos espumantes determinou-se o intervalo de valores possíveis de δ13C para que as bebidas estivessem em acordo com as normas. Em relação aos espumantes, quatro estavam fora do intervalo de valores estabelecido; para os espumantes moscatéis, nenhum estava em desacordo com a legislação brasileira. / The objective of this study was to analyze isotopically carbonic gas sparkling to detect tampering using the isotopic analysis method to determine the source of carbon dioxide (whether from plants the photosynthetic cycles C3 (grape and beet), C4 (sugar cane) or from another source. For this purpose, samples were analyzed Muscat commercial sparkling wine and sparkling wine, sparkling prepared in the laboratory, grape juice, sugar and commercial CO2. They also analyzed other carbonated beverages (mineral water, soft drinks, wines, etc.). The results were submitted to ANOVA and Tukey test for the detection of possible differences between the means of the isotopic ratios 13C / 12C, at a significance level of p <0.05. Following the Brazilian legislation for sparkling wines determined the possible range of values of δ13C for the drinks were in accordance with the rules. Regarding sparkling, four were outside the range established; for muscat sparkling, none was at odds with Brazilian law.
286

Irrigação deficitária em videira de vinho cv. Syrah durante o período chuvoso no semiárido

Correia, Joselina de Souza [UNESP] 31 July 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-31Bitstream added on 2014-06-13T18:30:35Z : No. of bitstreams: 1 correia_js_me_botfca.pdf: 402295 bytes, checksum: 099cc93f3511a57ff83eab684b636900 (MD5) / Universidade Estadual Paulista (UNESP) / As disponibilidades de radiação solar e de água para irrigação contribuem para a produção de uvas ao longo do ano no Vale do Submédio São Francisco. Diante da expansão da vitivinicultura nesta região, a demanda por pesquisas em relação ao manejo adequado e prático da videira para a região semiárida brasileira tem aumentado. Desta forma, o presente trabalho teve o objetivo de avaliar a influência de estratégias de irrigação na cultura da videira de vinho, e suas possíveis influências na produtividade e qualidade das uvas. O experimento foi conduzido na Embrapa Semiárido, em Petrolina -PE, entre 10 de novembro de 2010 a 28 de fevereiro de 2011, com a videira cv. Syrah/Paulsen 1103, plantada em espaçamento de 1 x 3 m, em um Argissolo Vermelho Amarelo Eutrófico Latossólico. O sistema de irrigação utilizado foi o gotejamento, com emissores espaçados em 0,5 m na linha de plantio, com vazão de 2,5 L.h-1. O delineamento utilizado foi o de blocos casualizados, com 3 tratamentos e 4 repetições. Os tratamentos foram: 1- irrigação plena (IP), irrigação realizada com base na reposição da evapotranspiração da cultura (ETc), durante todo o ciclo de produção; 2 - irrigação com déficit controlado (IDC), irrigação interrompida aos 65 dias após a poda de produção (dapp), porém com irrigações aos 91, 92 e 93 dapp; e 3 - irrigação deficitária (ID), irrigação interrompida aos 65 dapp até a colheita aos 110 dapp. A ETc foi estimada pela relação entre evapotranspiração de referência (ETo), e o coeficiente de cultura (Kc). O potencial hídrico foliar (Ψfoliar) foi medido em cada tratamento, do estádio fenológico de maturação até o estádio de cachos maduros. Durante o experimento, ocorreu uma precipitação total de 252 mm. A ETc durante... / The availability of solar radiation and water for irrigation contribute to the wine grape production throughout the year in the Lower Middle São Francisco Valley. In consequence of increase of vine growing area in this region, the research demand about suitable and feasible vine water management in the Brazilian semi-arid region has increased. Thus, this study aimed to evaluate the influence of irrigation strategies in vineyards, and their possible effects on yield and quality of wine grapes. The experiment was carried out at Embrapa Tropical Semi-arid, in Petrolina, State of Pernambuco, Brazil, from November 10, 2010, to February 28, 2011. The grapevive cv. Syrah, grafted on Paulsen 1103, was planted at a spacing grid of 1 x 3 m, in a Argissolo Vermelho Amarelo Eutrófico Latossólico. Drip irrigation was used, with emitters spaced 0.5 m within the plant row, with 2.5 L.h-1 flow. The design was a randomized complete block with three treatments and four replications. The treatments were: 1 - full irrigation (FI), where irrigation was performed based on crop evapotranspiration (ETc, mm) during all growing season, without water restriction to the vines; 2 – regulated deficit irrigation (RDI), where irrigation was performed based on ETc until 65 days after pruning (dap), but performed at 91, 92, and 93 dap and 3 – deficit irrigation (ID) – where irrigation interrupted at 65 dap until harvest at 110 dap. The ETc was estimated by the relationship between reference evapotranspiration (ETo), and crop coefficient (kc) for each phenological phase of vine. The leaf water potential (Ψpd) was measured... (Complete abstract click electronic access below)
287

Caracterização química, energética, aromática e sensorial de vinhos de mesa de uvas americanas

Uliana, Maíra Rodrigues [UNESP] 05 June 2013 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:31:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-05Bitstream added on 2014-06-13T20:02:34Z : No. of bitstreams: 1 uliana_mr_dr_botfca.pdf: 692060 bytes, checksum: ec95080add003b64282fe9edf5a1c7f3 (MD5) / Os objetivos deste trabalho foram caracterizar físico-química, energética, aromática e sensorialmente vinhos provenientes de uvas americanas e/ou híbridos produzidos em vinícolas brasileiras. Foram utilizados vinhos provenientes de uvas tintas das variedades Bordô, Isabel e Máximo, e de uvas brancas das variedades Niagara e BRS Lorena. Para a caracterização físico-química e energética os vinhos foram analisados pelas seguintes determinações químicas: teor alcoólico; densidade; extrato seco total e reduzido; relação álcool em peso/extrato seco reduzido, açúcares redutores; acidez total, volátil e fixa; pH; dióxido de enxofre total e livre; e valor energético. As amostras foram avaliadas por cromatografia gás-líquido, em um cromatógrafo gasoso equipado com um injetor split/splitless e um detector de ionização de chama (DIC), para a quantificação de seus compostos volátéis majoritários. Já para a porção dos compostos voláteis minoritários, as frações livre e glicosilada desses vinhos foram extraídas e analisadas utilizando um sistema GC-MS constituído por cromatógrafo gasoso e detector de espectro de massas. Todos os compostos foram quantificados como equivalentes ao 4-nonanol. Na análise sensorial foi utilizado o teste de aceitação por escala hedônica, para avaliação da aceitabilidade desses vinhos. Para os resultados da caracterização físico-química, enegética, compostos voláteis majoritários e teste escala hedônica foi realizada análise de variância e as médias foram comparadas pelo teste de Tukey. A análise de componentes principais (APC) foi utilizada para avaliar a porção dos compostos voláteis minoritários. Todos os vinhos analisados apresentaram parâmetros físico-químicos dentro dos estipulados pela legislação brasileira. Os vinhos varietais Bordô e Isabel possuem mais... / The objectives of this study were to characterize physical-chemical, energy, aromatic and sensory the wines from American grapes and/or hybrids produced in Brazilian wineries. It has been used wines from red grapes varieties Bordô, Isabel and Máximo, and white grape varieties Niagara and BRS Lorena. The wines physical-chemical and energy characterization were analyzed through the following chemical determinations: alcohol content, density, total and reduced dry extract, alcohol in weight/reduced dry extract ratio, reducing sugars, total, volatile and fixed acidity, pH, free and total sulfur dioxide, and energy value. The samples were analyzed by gas chromatography in a gas chromatograph equipped with a split/splitless injector and a flame ionizing detector (FID), for the major volatile compounds quantification. As for the minority portion of volatile compounds, the free and glycosylated fractions of those wines were extracted and analyzed using a GC-MS system consisting of a gas chromatograph and a mass spectral detector. All compounds were quantified as 4-nonanol equivalent. The sensory analysis used the acceptance test by hedonic scale, for the acceptability evaluation of these wines. For the results of physical-chemical characterization, energetic, major volatile compounds and hedonic scale test it has been performed variance analysis and the means were compared by Tukey test. The principal component analysis (PCA) was used to assess the volatile minority compounds portion. All wines analyzed showed physic-chemical parameters within the stipulated by the Brazilian law. The varietal wines Bordô and Isabella have more and in a higher concentration, responsible compounds for the foxy aroma of wines from American varieties, as compared with the varietal Máximo. The varietal... (Complete abstract click electronic access below)
288

Atividade biológica de resíduos de vinificação de vitis labrusca

Scola, Gustavo 22 March 2013 (has links)
Anualmente, a produção mundial de vinhos gera cerca de 20 milhões de toneladas de resíduos, os quais, na maior parte, são descartados no meio ambiente. Dados prévios demostraram que é possível obter-se compostos flavan-3-ol a partir de diferentes resíduos de vinificação, com significativa atividade antioxidante. Em vista disso, o objetivo deste trabalho foi investigar as atividades neuroprotetora, hepatoprotetora, genotóxica, mutagênica e citotóxica do extrato aquoso de sementes de resíduos de vinificação de Vitis labrusca, variedade Bordo, avaliando o mecanismo de ação do mesmo. Os resultados mostraram que o extrato minimiza os danos oxidativos aos lipídeos e proteínas em córtex cerebral, cerebelo, hipocampo, e no fígado de ratos tratados com pentilenotetrazol. Além disso, o extrato não alterou o comportamento locomotor dos ratos e não apresentou efeito genotóxico (ensaio cometa) ou mutagênico em linfócitos de ratos e células de levedura Saccharomyces cerevisiae, respectivamente. O tratamento com o extrato diminui a depleção das proteínas do complexo I da cadeia transportadora de elétrons na mitocôndria em células de neuroblastoma humano (SH-SY5Y) tratadas com H2O2. Em doses de 0,1 e 1mg/mL, o extrato mostrou-se citotóxico para as linhagens de câncer de fígado (HepG2) e de mama (MCF-7). Este efeito foi acompanhado pelo aumento da produção de óxido nítrico, da expressão de p53 e da fragmentação do DNA. Uma diminuição significativa nos níveis de expressão da PARP total foi observada na linhagem HepG2. Na linhagem MCF-7, o tratamento com o extrato de V. labrusca aumentou a expressão das proteínas Bax e AIF, e diminuiu a expressão da PARP total. A expressão da proteína Her-2 apresentou-se diminuída em células HepG2 e MCF-7 tratadas com o extrato. Estes resultados mostram importantes efeitos biológicos do extrato de resíduos de vinificação de V. labrusca, variedade Bordo. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-06-17T13:06:13Z No. of bitstreams: 1 Tese Gustavo Scola.pdf: 8668323 bytes, checksum: adc4c46aea3167d99be63113958637f3 (MD5) / Made available in DSpace on 2014-06-17T13:06:13Z (GMT). No. of bitstreams: 1 Tese Gustavo Scola.pdf: 8668323 bytes, checksum: adc4c46aea3167d99be63113958637f3 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Every year, the worldwide wine production generates about 20 million tons of waste, which usually end up being discarded in the environment. Previous data showed that it is possible to obtain flavan-3-ol compounds from different winery wastes with significant antioxidant activity. Thus, the aim of this work was to investigate the neuroprotective, hepatoprotective, genotoxic, mutagenic and cytotoxic activities of aqueous winery seeds extract from Vitis labrusca, cv. Bordo. The results showed that the extract minimizes the oxidative damage to lipids and proteins in the cerebral cortex, cerebellum, hippocampus and liver of rats. Also, the extract did not alter locomotor behavior, and it was non-genotoxic (comet assay) or nonmutagenic in lymphocytes from rats, and in Saccharomyces cerevisiae cells, respectively. The treatment with the extract was able to prevent depletion of mitochondrial eletron transfer chain complex I proteins in neuroblastoma cells (SH-SY5Y) treated with H2O2. At doses of 0.1 and 1mg/mL, the extract was found to be cytotoxic to liver (HepG2) and breast (MCF-7) cancer cell lines. This effect was accompanied with an increase in nitric oxide production, increase in the expression of p53, and increase in DNA damage index. A significant decrease in the expression levels of total PARP was observed in HepG2 cell line. In MCF-7 cells, V. labrusca extract treatment increased the expression levels of Bax and AIF proteins, and decreased the expression levels of total PARP. The expression levels of Her-2 protein were found to be decreased in HepG2 and MCF-7 cells after V. labrusca extract treatment. These results show significant biological effects of V. labrusca winery wastes extract, cv. Bordo.
289

Clarificação de vinho branco por microfiltração utilizando diferentes membranas cerâmicas e compósitas

Cristofoli, Kélen 15 December 2016 (has links)
A microfiltração tangencial aplicada à clarificação de vinho branco tem se tornado uma importante alternativa aos processos convencionais de filtração na indústria vinícola, como a filtração por terras diatomáceas, trasfega e centrifugação. O uso de membranas cerâmicas tem despertado interesse para esta finalidade. Neste trabalho, diferentes membranas cerâmicas e compósitas tubulares, mono e multicanal, de diferentes tamanhos de poro, foram avaliadas quanto à sua morfologia e testes de permeabilidade hidráulica e do vinho branco, a fim de verificar a influência da estrutura destas no fluxo de vinho branco permeado, bem como, avaliar a presença de resíduos sólidos suspensos no vinho permeado decorrente de seu processo de clarificação. As membranas foram caracterizadas por difração de raios X (DRX), microscopia eletrônica de varredura por emissão de campo (FESEM), espectroscopia de dispersão de energia (EDS), porosimetria por intrusão de mercúrio, testes de permeabilidade e retenção de proteínas. O tamanho médio de poro apresentado pelas membranas variou de 0,0056 a 5,0 µm. As membranas compósitas apresentaram ótima retenção proteica, 99%, para solutos com massa molar acima de 45 kDa. Membranas de α-alumina tratadas termicamente a 1450ºC e membranas compósitas de α-alumina/poliamida 66 demonstraram, em média, redução de 99,9% da turbidez inicial do vinho, sendo possível reduzir de 720 NTU para, em média, 0,30 NTU, com possibilidade de estabilização tartárica em sete dias e fluxos de permeado que variaram de 60,8 a 8,8 L.m-2.h-1, respectivamente, a 1,0 bar de pressão. Por outro lado, membranas de mulita e titânia não demonstraram eficiência para a clarificação, sendo que o vinho permeado pela membrana de mulita apresentou turbidez de 20 NTU e aumento do índice de polifenóis totais (IPT). Membranas compósitas permitiram a redução de 37% no valor de IPT do vinho branco. O baixo valor de turbidez obtido nos vinhos permeados pelas membranas de alumina e compósitas demonstra forte perspectiva da utilização destas membranas na clarificação do vinho branco. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2017-03-24T18:24:14Z No. of bitstreams: 1 Tese Kélen Cristofoli.pdf: 5048002 bytes, checksum: 8a229e6f22e8e9bddc2c19f7a5060a08 (MD5) / Made available in DSpace on 2017-03-24T18:24:14Z (GMT). No. of bitstreams: 1 Tese Kélen Cristofoli.pdf: 5048002 bytes, checksum: 8a229e6f22e8e9bddc2c19f7a5060a08 (MD5) Previous issue date: 2017-03-24 / The tangential microfiltration applied to the clarification of white wine has become an important alternative to conventional filtration processes in the wine industry, for example, the filtration diatomaceous earth, land transfer and centrifugation. The use of ceramic membranes has awakened interest for this purpose. In this work, different and tubular composite ceramic membranes, mono and multi-channel, of different sizes of pore, were evaluated for their morphology and hydraulic permeability tests and white wine, in order to verify the influence of the structure of these in white wine flow permeated as well, evaluate the presence of suspended solids in the waste wine due to its process of clarification. The membranes were characterized by x-ray diffraction (XRD), scanning electron microscopy by field emission (FESEM), energy dispersive spectroscopy (EDS), porosimetria by mercury intrusion tests, permeability and protein retention. The average pore size presented by membranes ranged from 0.0056 to 5.0 µm. Composite membranes showed great protein retention, 99%, for solutes with molecular weight up to 45 kDa. α-alumina membranes treated thermally to 1450ºC and composite membranes of α-alumina/polyamide 66 showed, on average, 99.9% reduction of wine’s turbidity, being possible to reduce from 720 NTU to average 0.30 NTU, with possibility of tartaric stabilization in seven days and permeate fluxes that ranged from 60.8 to 8.8 L. m-2h-1, respectively, the 1.0 bar pressure. On the other hand, mullite and titania membranes have not shown effectiveness for clarification, the wine permeated by the membrane of mullite presented turbidity of 20 NTU and increase the rate of total polyphenols (IPT). Composite membranes have enabled the reduction of 37% in the value of IPT of the white wine. The low turbidity value obtained in wine permeated by composite and alumina membranes, strong perspective of use demonstrates of these membranes in the clarification of white wine.
290

Irrigação deficitária em videira de vinho cv. Syrah durante o período chuvoso no semiárido /

Correia, Joselina de Souza, 1978. January 2012 (has links)
Orientador: Luís Henrique Bassoi / Banca: Raimundo Leite Cruz / Banca: Antonio Odair Santos / Resumo: As disponibilidades de radiação solar e de água para irrigação contribuem para a produção de uvas ao longo do ano no Vale do Submédio São Francisco. Diante da expansão da vitivinicultura nesta região, a demanda por pesquisas em relação ao manejo adequado e prático da videira para a região semiárida brasileira tem aumentado. Desta forma, o presente trabalho teve o objetivo de avaliar a influência de estratégias de irrigação na cultura da videira de vinho, e suas possíveis influências na produtividade e qualidade das uvas. O experimento foi conduzido na Embrapa Semiárido, em Petrolina -PE, entre 10 de novembro de 2010 a 28 de fevereiro de 2011, com a videira cv. Syrah/Paulsen 1103, plantada em espaçamento de 1 x 3 m, em um Argissolo Vermelho Amarelo Eutrófico Latossólico. O sistema de irrigação utilizado foi o gotejamento, com emissores espaçados em 0,5 m na linha de plantio, com vazão de 2,5 L.h-1. O delineamento utilizado foi o de blocos casualizados, com 3 tratamentos e 4 repetições. Os tratamentos foram: 1- irrigação plena (IP), irrigação realizada com base na reposição da evapotranspiração da cultura (ETc), durante todo o ciclo de produção; 2 - irrigação com déficit controlado (IDC), irrigação interrompida aos 65 dias após a poda de produção (dapp), porém com irrigações aos 91, 92 e 93 dapp; e 3 - irrigação deficitária (ID), irrigação interrompida aos 65 dapp até a colheita aos 110 dapp. A ETc foi estimada pela relação entre evapotranspiração de referência (ETo), e o coeficiente de cultura (Kc). O potencial hídrico foliar (Ψfoliar) foi medido em cada tratamento, do estádio fenológico de maturação até o estádio de cachos maduros. Durante o experimento, ocorreu uma precipitação total de 252 mm. A ETc durante... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The availability of solar radiation and water for irrigation contribute to the wine grape production throughout the year in the Lower Middle São Francisco Valley. In consequence of increase of vine growing area in this region, the research demand about suitable and feasible vine water management in the Brazilian semi-arid region has increased. Thus, this study aimed to evaluate the influence of irrigation strategies in vineyards, and their possible effects on yield and quality of wine grapes. The experiment was carried out at Embrapa Tropical Semi-arid, in Petrolina, State of Pernambuco, Brazil, from November 10, 2010, to February 28, 2011. The grapevive cv. Syrah, grafted on Paulsen 1103, was planted at a spacing grid of 1 x 3 m, in a Argissolo Vermelho Amarelo Eutrófico Latossólico. Drip irrigation was used, with emitters spaced 0.5 m within the plant row, with 2.5 L.h-1 flow. The design was a randomized complete block with three treatments and four replications. The treatments were: 1 - full irrigation (FI), where irrigation was performed based on crop evapotranspiration (ETc, mm) during all growing season, without water restriction to the vines; 2 - regulated deficit irrigation (RDI), where irrigation was performed based on ETc until 65 days after pruning (dap), but performed at 91, 92, and 93 dap and 3 - deficit irrigation (ID) - where irrigation interrupted at 65 dap until harvest at 110 dap. The ETc was estimated by the relationship between reference evapotranspiration (ETo), and crop coefficient (kc) for each phenological phase of vine. The leaf water potential (Ψpd) was measured... (Complete abstract click electronic access below) / Mestre

Page generated in 0.0509 seconds