Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The effect of partial rootzone drying (PRD) on the composition of grape and wine secondary metabolites was investigated. At harvest, total anthocyanin and phenolic concentration in fruit of Vitis vinifera L. cvs Shiraz and Cabernet Sauvignon was either unaltered or increased in response to PRD over two seasons. Where an increase in anthocyanin concentration was found with PRD, this was found to be independent of berry size. Rather, increases in anthocyanin concentration were most likely due to an increase in anthocyanin production in the berry skins. In Cabemet Sauvignon wine made from one vintage, total colour was enhanced by 10% in response to the PRD treatment, although in that season total anthocyanin concentration was unaltered in the fruit or wine. This colour enhancement was due to an increase in coloured pigments in copigmented or polymeric form, that is in association with other anthocyanins or phenolic compounds. This is a significant finding, as it shows that the colour of wine is not dependent upon anthocyanin concentration alone, but rather on reactions taking place during winemaking and wine-ageing. The colour enhancement was found to be maintained after a year's ageing in the bottle. A key question which arises from this work is which component(s) of total phenolics in PRD-treated wines is responsible for this effect. Preliminary investigation of seed proanthocyanidins and flavan-3-ols showed that their content per berry was unaltered by the PRD treatment. However, where berry weight was decreased due to PRD, the concentration of these seed tannins was increased on a per gram basis. This could potentially lead to an increased contribution of seed tannins to total wine phenolics in PRD wines. The effect of this is two-fold. Firstly, seed tannins are known to be weak copigments and could in part account for the increased copigmentation and polymerisation of anthocyanins observed with PRD. Secondly, an increased concentration of seed tannins in PRD wines could alter wine astringency and mouth feel properties. In both fruit and wine samples, PRD was found to cause a decrease in the contribution malvidin-glucosides to total anthocyanins. Thus, levels of non-malvidin glucosides, namely delphinidin and cyanidin, were increased by PRD. This effect was investigated as fruit matured post-veraison, and was evident from early in berry development. Preliminary results indicate that this response requires the presence of high incident light levels to the fruit during development, but is not mediated by increased bunch exposure alone. Shading of fruit led to a significant decrease in all anthocyanin types, and caused a shift in the ratio of acetyl- and 3p-coumary1-glucosides to mono-glucosides. The PRD treatment, however, did not cause changes in the proportions of acetyl-, 3p-coumary1-and mono-glucoside anthocyanins. These results show that the response of the anthocyanin pathway to the PRD treatment is most likely mediated by physiological signals within the fruit and vine, rather than due to a change in bunch zone microclimate. An important class of potential flavour and aroma compounds in grapes are the C₁₃-norisoprcnoids. As the precursors to these compounds are fruit-derived, rather than by-products of fermentation, the potential exists for their manipulation using viticultural practices. Previously, bunch exposure has been thought to be the primary factor mediating the final levels of C₁₃-norisoprenoids in fruit. The current study has shown that total shading of developing bunches using artificial means led to a significant decrease in the levels of these compounds in both fruit and wine samples of Shiraz. However, when fruit of this variety was subjected to natural changes in bunch exposure, resulting from alterations in canopy structure, the response of the C₁₃-norisoprenoids to these conditions was either small or insignificant. Of the three C₁₃-norisoprenoids studied, namely ß -damascenone, ß -ionone and TDN, only TDN showed a significant response to bunch exposure under these conditions. Preliminary results of this study on Shiraz indicated that the concentration of the C₁₃-norisoprenoids ß -damascenone and TDN can potentially be influenced by changes in vine shoot vigour and canopy architecture, induced by a water-deficit. This finding was validated by a study on Cabernet Sauvignon, where the effect of PRD on fruit C₁₃-norisoprenoids was investigated. The concentrations of the C₁₃-norisoprenoids ß -damascenone, ß -ionone and TDN were shown to be increased by up to 30% in response to PRD in Cabernet Sauvignon fruit over two vintages. The changes in these compounds in the fruit were associated with increased levels of the carotenoids lutein and ß -carotene, which are potential precursors to the C₁₃-norisoprenoids. The results of the current study have shown that the regulation of C₁₃- norisoprenoid concentration in grapes and wine may not be primarily due to the level of incident light on developing bunches, although the presence of light is necessary for their production. Rather, the effect of deficit irrigation practices on whole-vine physiology and vine shoot vigour holds stronger potential as a tool for the viticultural manipulation of these compounds in fruit and wine. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1129092 / Thesis (Ph.D.) -- University of Adelaide, School of Wine and Agriculture, 2004

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The effect of partial rootzone drying (PRD) on the composition of grape and wine secondary metabolites was investigated. At harvest, total anthocyanin and phenolic concentration in fruit of Vitis vinifera L. cvs Shiraz and Cabernet Sauvignon was either unaltered or increased in response to PRD over two seasons. Where an increase in anthocyanin concentration was found with PRD, this was found to be independent of berry size. Rather, increases in anthocyanin concentration were most likely due to an increase in anthocyanin production in the berry skins. In Cabemet Sauvignon wine made from one vintage, total colour was enhanced by 10% in response to the PRD treatment, although in that season total anthocyanin concentration was unaltered in the fruit or wine. This colour enhancement was due to an increase in coloured pigments in copigmented or polymeric form, that is in association with other anthocyanins or phenolic compounds. This is a significant finding, as it shows that the colour of wine is not dependent upon anthocyanin concentration alone, but rather on reactions taking place during winemaking and wine-ageing. The colour enhancement was found to be maintained after a year's ageing in the bottle. A key question which arises from this work is which component(s) of total phenolics in PRD-treated wines is responsible for this effect. Preliminary investigation of seed proanthocyanidins and flavan-3-ols showed that their content per berry was unaltered by the PRD treatment. However, where berry weight was decreased due to PRD, the concentration of these seed tannins was increased on a per gram basis. This could potentially lead to an increased contribution of seed tannins to total wine phenolics in PRD wines. The effect of this is two-fold. Firstly, seed tannins are known to be weak copigments and could in part account for the increased copigmentation and polymerisation of anthocyanins observed with PRD. Secondly, an increased concentration of seed tannins in PRD wines could alter wine astringency and mouth feel properties. In both fruit and wine samples, PRD was found to cause a decrease in the contribution malvidin-glucosides to total anthocyanins. Thus, levels of non-malvidin glucosides, namely delphinidin and cyanidin, were increased by PRD. This effect was investigated as fruit matured post-veraison, and was evident from early in berry development. Preliminary results indicate that this response requires the presence of high incident light levels to the fruit during development, but is not mediated by increased bunch exposure alone. Shading of fruit led to a significant decrease in all anthocyanin types, and caused a shift in the ratio of acetyl- and 3p-coumary1-glucosides to mono-glucosides. The PRD treatment, however, did not cause changes in the proportions of acetyl-, 3p-coumary1-and mono-glucoside anthocyanins. These results show that the response of the anthocyanin pathway to the PRD treatment is most likely mediated by physiological signals within the fruit and vine, rather than due to a change in bunch zone microclimate. An important class of potential flavour and aroma compounds in grapes are the C₁₃-norisoprcnoids. As the precursors to these compounds are fruit-derived, rather than by-products of fermentation, the potential exists for their manipulation using viticultural practices. Previously, bunch exposure has been thought to be the primary factor mediating the final levels of C₁₃-norisoprenoids in fruit. The current study has shown that total shading of developing bunches using artificial means led to a significant decrease in the levels of these compounds in both fruit and wine samples of Shiraz. However, when fruit of this variety was subjected to natural changes in bunch exposure, resulting from alterations in canopy structure, the response of the C₁₃-norisoprenoids to these conditions was either small or insignificant. Of the three C₁₃-norisoprenoids studied, namely ß -damascenone, ß -ionone and TDN, only TDN showed a significant response to bunch exposure under these conditions. Preliminary results of this study on Shiraz indicated that the concentration of the C₁₃-norisoprenoids ß -damascenone and TDN can potentially be influenced by changes in vine shoot vigour and canopy architecture, induced by a water-deficit. This finding was validated by a study on Cabernet Sauvignon, where the effect of PRD on fruit C₁₃-norisoprenoids was investigated. The concentrations of the C₁₃-norisoprenoids ß -damascenone, ß -ionone and TDN were shown to be increased by up to 30% in response to PRD in Cabernet Sauvignon fruit over two vintages. The changes in these compounds in the fruit were associated with increased levels of the carotenoids lutein and ß -carotene, which are potential precursors to the C₁₃-norisoprenoids. The results of the current study have shown that the regulation of C₁₃- norisoprenoid concentration in grapes and wine may not be primarily due to the level of incident light on developing bunches, although the presence of light is necessary for their production. Rather, the effect of deficit irrigation practices on whole-vine physiology and vine shoot vigour holds stronger potential as a tool for the viticultural manipulation of these compounds in fruit and wine. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1129092 / Thesis (Ph.D.) -- University of Adelaide, School of Wine and Agriculture, 2004

Abstract Purpose: The aim of this thesis is to explore the impact of environmental friendly wine packageson wine consumption in Sweden. While there are many different factors influencing this issue,the overall focus of this thesis has been on the perception of the quality of 'Green wine packaging'on behalf of the consumers. Method: A quantitative approach in form of an online survey was followed by an qualitativeapproach in form of semi-structured interviews. While the quantitative approach was the mainapproach, the qualitative approach was used for further interpretation. Conclusions: Despite a great environmental awareness and a great engagement in recyclingactivities in Sweden, the results of this study shows that consumer prefer wine in traditional glassbottles. Quality is considered to be the most important element when purchasing wine and itappears that consumer perceive a low level of quality of wine in Green packages which in turnlowers their aesthetical and hedonic expectations. The quality of the wine appear also to be moreimportant than the environmental issue.

The aim of this diploma thesis is the identification of yeasts isolated during grape must fermentation. The must was obtained from Pinot Noir varieties grown in an integrated and organic production. The partner of this thesis was a winery Holánek. In the theoretical part of the work was the emphasis on information about the determinants quality of wine, yeasts and PCR-RFLP method. Physiological properties of yeasts were described and also the principles of the polymerase chain reaction (PCR) were explained. In the experimental part of the thesis was applied molecular biology method PCR-RFLP for identification of yeasts. The specific segment of DNA was amplified (5, 8S-ITS rDNA sequencing) with the help of ITS1 and ITS4 primers. The incurred amplicons were digested by applying restriction endonucleases: HaeIII, HinfI and TaqI. Subsequently the restriction fragments were analysed by using of electrophoresis. The yeasts were identified and classified by taxonomy on the level of genera and species.

No description available.

The relationship between soil and wine quality has been recognized for generations but has had limited scientific validation. Vineyard soils in the eastern United States are largely unstudied although proper site selection and good soil management have the potential to improve fruit composition for high-quality wine production. Soils that provide excessive plant-available nutrients and water often produce vigorous vegetative growth and negatively influence fruit chemistry. We investigated three aspects of Eastern vineyard soils, including potassium availability, methods of reducing infiltration, and the influence of topsoil on fruit chemistry. Our first goal was to determine the best soil sampling, processing, and extraction methods for predicting potassium availability in Mid-Atlantic vineyard soils. Excessive potassium can result in high pH fruit, which negatively affects wine quality, but until now the best methods for predicting soil-available potassium had not been investigated. We found that moist-extracted soil sampled from 0-38 cm appear to best be suited predicting vine tissue potassium. Our second goal was to test methods of reducing rain infiltration at critical times during the growing season. One of the soil stabilizers we tested successfully reduced infiltration in field trials. Vineyard trials in 2021 were compromised by dry weather, but further research is ongoing. Our final project involved a three-year investigation where we attempted to isolate the influence of soil properties on grapevines and fruit composition by monitoring vines and fruit in single vineyard blocks. The most consistent result was positive relationships between topsoil and fruit titratable acidity, suggesting that the fruit was ripening earlier in vines growing in thinner topsoil. Topsoil depth better explained differences in fruit titratable acidity than other explanatory variables including crop load and sunlight exposure of fruit. Overall, this research increased our understanding of the soil properties that influence vine growth and fruit chemistry in the Eastern US. The results will help growers improve sampling methods, fruit chemistry, and increase resilience to soil and climate related challenges. / Doctor of Philosophy / The relationship between grapes, wine, and soil has been acknowledged since the Middle Ages when monks recognized that vineyards in different places produced different-tasting wine. However, it is difficult to determine exactly how soil affects grapes and wine. In the eastern United States, growers knew that some soils were not the best for growing high quality grapes for wine, such as those that provide excessive nutrients or water to the vines, but there was little information or scientific research about it. We wanted to help growers by investigating soil properties that affect fruit quality as well as potential soil management strategies that could improve fruit quality. We fine-tuned the process of collecting, processing, and analyzing vineyard samples that growers use to determine the potassium status of their vines. Potassium can affect fruit quality so testing for it before it can affect fruit quality is crucial. We found that sampling soil to a deeper depth than usual and keeping the sample moist instead of drying it were the best practices. We also determined the best way to complete the lab analysis to best predict how much potassium the soil can provide to the vines. For our second project, we found that commercial material intended for stabilizing dirt roads slowed the seeping of rain into soil. Future research will see if vineyards can use the soil stabilizer to reduce soil water during mid-summer rains to improve fruit quality. Our final project involved monitoring vineyards over three years to see how differences in soil properties affected vine growth and fruit chemistry. The main difference in soil was the thickness of topsoil throughout each vineyard. Where there was thin topsoil, the vines were smaller and produced fruit that was less acidic. These results are likely because those fruit were ripening earlier, but we were not able to identify a specific soil property that was affecting the fruit chemistry. Overall, our results will help vineyard growers better manage their soil to hopefully produce better-quality fruit and wine.

Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Grapevine performance and wine quality are influenced by various factors, two of the most important being the availability and quality of irrigation water. In relatively dry countries such as South Africa the conservation and effective use of water is of utmost importance. Expected increases in temperature and decreases in rainfall in the future due to climate change impacts highlights the importance of water conservation. This inspired investigations into possible alternative irrigation water sources and therefore the possibility of vineyard irrigation using winery wastewater is of utmost importance for the sustainability of the wine industry. Winery wastewater contains higher concentrations of certain elements other than water generally used for vineyard irrigation, the most important differences being Na and K levels. Furthermore, winery wastewater contains larger populations of microorganisms such as yeasts, lactic acid bacteria and acetic acid bacteria, typical associated with wine production. If irrigation using winery wastewater affects the uptake of certain elements or alters grapevine water status, it may affect grapevine growth, juice and wine composition. Furthermore, if juice and wine composition is affected wine composition and sensorial quality may be affected. Cabernet Sauvignon/99R grapevines, growing in a sandy soil in the Breede River Valley, were subjected to eight irrigation treatments using augmented winery wastewater in addition to irrigation using raw river water as control. The study was carried out during the 2010/11 and 2011/12 seasons. The various wastewater irrigation treatments were made up by augmenting winery wastewater with raw river water to obtain a target chemical oxygen demand (COD) concentration. In this study, the level of COD in the irrigation water is a direct indication of water quality, the two being indirectly proportional. The eight wastewater irrigation treatments ranged from 100 mg/L COD up to 3000 mg/L COD. The first objective of the study was to determine the effect of irrigation using augmented winery wastewater on grapevine response, with regards to vegetative growth, berry development and berry composition. The various wastewater irrigation treatments did not affect grapevine vegetative growth or reproductive growth, including yield, throughout berry development up to harvest. Berry sugar accumulation and evolution in acid concentrations were also not affected. An increase in berry juice pH was observed with an increase in the level of COD in the augmented winery wastewater only in the second season. The amount of elements, ions and heavy metals in juice was not affected by wastewater irrigation, indicating that there was no absorption by the grapevines. Berry skin thickness, colour and phenolic content as well as yield and its associated components were not affected by irrigation using augmented winery wastewater. The second objective of the study was to determine the effect of irrigation using augmented winery wastewater on wine microbial and chemical composition, fermentation performance and wine sensorial characteristics. The natural yeast and bacteria flora of juice was not affected by the various wastewater irrigation treatments. In addition, the ability of the inoculated yeast and lactic acid bacteria strains to conduct their respective fermentation processes were not affected. With the exception of total titratable acidity (TTA) and pH, irrigation using augmented winery wastewater did not affect wine chemical composition with regards to basic wine parameters as well as colour, phenolic and tannin composition. Similar to juice, phosphorus and selected ions were not affected. None of the measured wine sensorial characteristics were affected by irrigation using augmented winery wastewater. The third objective of the study was to investigate the effect of direct contact between berries and winery wastewater on wine sensorial characteristics. The study focussed on the transference of off-flavours from the wastewater into the wine and the occurrence of off-flavours as a response to contact with winery wastewater. Wine colour and general sensory wine descriptives were not affected by direct contact with winery wastewater. The presence of a winery wastewater-like off-odour and volatile acidity was, however, more detectable in wines made from berries that were in contact with the most concentrated wastewater. Therefore, it may be possible for off-odours to be transferred from the winery wastewater into the wines, or that off-odours are formed as a direct or indirect result of contact with winery wastewater. Under the given conditions, results obtained in this two seasons of the study suggest that irrigation using augmented winery wastewater does not affect grapevine performance or wine quality substantially. The major impact that was observed was an increase in wine pH and a decreasing trend in TTA. Both these parameters could be rectified by simply adding acid to the wines. Therefore, irrigation using augmented winery wastewater may be considered as a possible future alternative source for vineyard irrigation. It is, however, important to remember that some of the effects of wastewater irrigation may be cumulative and could possibly arise only after several years. Furthermore, different field conditions and cultivars may respond differently. / AFRIKAANSE OPSOMMING: Wingerd prestasie en wyngehalte word deur verskeie faktore beïnvloed waarvan twee van die belangrikste die beskikbaarheid en gehalte van besproeiingswater is. In relatiewe droë lande soos Suid Afrika is waterbesparing en die effektiewe benutting van water hulpbronne van uiterste belang. Die verwagte toename in temperatuur en afname in reënval in die toekoms as gevolg van klimaatsveranderinge plaasdieklem op op die belangrikheid van waterbesparing. Dit het navorsing om moontlike alternatiewe vorme van besproeiingswater te ontdek geïnspireer. Na aanleiding van hierdie faktore word daar toenemend gefokus op navorsing oor die moontlikheid om kelder afvalwater as alternatiewe bron van besproeiings water vir wingerde te benut. Kelder afvalwater bevat hoër konsentrasie van sekere elemente as water wat onder normale omstandighede gebruik word vir die besproeiing van wingerde, die belangrikste verskille was die vlakke van Na en K. Benewens die hoër konsentrasie van sekere elemente bevat kelder afvalwater ook groot populasies van mikroörganismes soos giste, melksuurbakterieë en asynsuurbakterieë, tipies geassosieerd met wynbereiding. Indien besproeiing met kelder afvalwater die opname van sekere elemente of die plant water status beϊnvloed, mag wingerd groei, sap en wyn samestelling beϊnvloed word. Daar benewens, indien die mikrobiese samestelling van die sap en wyn beϊnvloed word sal die samestelling en sensoriese gehalte van die wyn moontlik beϊnvloed word. Cabernet Sauvignon/99R wingerde, geleë in sanderige grond in die Breede Rivier Vallei, is onderwerp aan besproeiing met agt verskillende konsentrasies van verdunde kelder afvalwater, bykomend tot besproeiing met onbehandelde rivier water wat as kontrole gedien het. Hierdie studie is uitgevoer gedurende die 2010/11 en 2011/12 seisoene. Die teiken besproeiings konsentrasies is verkry deur kelder afvalwater met onbehandelde rivier water te verdun tot ‘n sekere chemiese suurstofbehoefte (CSB) konsentrasie bereik is. Die CSB is in hierdie studie ‘n direkte aanduiding van watergehalte, die twee was indirek eweredig tot mekaar. Die agt CSB konsentrasies waarteen die afvalwater besproei is wissel tussen 100 mg/L CSB en 3000 mg/L CSB. Die eerste doelwit van die studie was om te bepaal wat die effek van besproeiing met verdunde kelder afvalwater op wingerdprestasie, met spesifieke verwysing na vegetatiewe groei, korrelontwikkeling en korrelsamestelling is. Wingerd vegetatiewe en reproduktiewe groei, insluitende opbrengs, is op geen stadium tydens korrelontwikkeling tot en met oes beïnvloed nie. Die laai van suikers gedurende rypwording, sowel as verskuiwings in suurkonsentrasie, is nie deur besproeiing met kelder afvalwater beïnvloed nie. In die tweede seisoen is ‘n toename in sap pH waargeneem soos die CSB konsentrasie van die besproeiings water toegeneem het. Die element, ioon en swaar metaal samestelling van sap was nie beïnvloed deur besproeiing met afvalwater nie wat aandui dat daar geen opname was deur die wingerd nie. Die dikte, kleur en fenoliese samestelling van druifdoppe is ook nie beïnvloed nie. Die tweede doelwit van die studie was om te bepaal wat die effek van besproeiing met verdunde kelder afvalwater op wyn mikrobiese en chemiese samestelling, fermentasie effektiwiteit en wyn sensoriese eienskappe is. Die verskeie afvalwater besproeiings behandelings het geen effek op die natuurlike gis of bakterieë flora van die sap gehad nie. Die vermoë van die geïnokuleerde gis en melksuurbakterieë om hul afsonderlike fermentasie prosesse te voltooi is ook nie beïnvloed nie. Met die uitsondering van totale titreerbare suur (TTS) en pH, is die chemiese samestelling van wyne met betrekking tot basiese wyn parameters, kleur, fenole en tanniene nie beïnvloed nie. Soortgelyk aan sap is wyn fosfor en geselekteerde ioon samestelling nie geaffekteer nie. Die sensoriese karakteristieke was eenders vir wyne van alle behandelings. Die derde doelwit van die studie was om te bepaal wat die effek wat direkte kontak van kelder afvalwater met druiwekorrels op wyn sensoriese eienskappe het. Hierdie studie het gefokus op die oordrag van afgeure vanaf kelder afvalwater na die wyne sowel as die voorkoms van afgeure as ‘n reaksie op kontak met kelder afvalwater. Wyn kleur en algemene sensoriese eienskappe is nie geaffekteer deur kontak tussen druiwe en kelder afvalwater nie. Kelder afvalwater-geassosieerde afgeure en vlugtige suur was meer duidelik waarneembaar in wyne wat gemaak is van druiwe wat in kontak was met die meer gekonsentreerde afvalwater. Dit mag dus moontlik wees dat afgeure vanaf kelder afvalwater oorgedra word na wyne, of dat sekere afgeure gevorm word as ‘n direkte of indirekte reaksie op kontak met kelder afvalwater. Onder die gegewe toestande oor die twee jaar studie periode het resultate getoon dat besproeiing met verdunde kelder afvalwater nie wingerdprestasie en wyn gehalte aansienlik beïnvloed nie. Die grootste impak wat afvalwater besproeiing gehad het, was om ‘n toename in wyn pH en ‘n tendens tot afname in TTS te veroorsaak. Deur eenvoudig suur by die wyn te voeg kan albei hierdie probleme reg gestel word. Op grond van hierdie bevindings kan besproeiing met verdunde kelder afvalwater moontlik as toekomstige bron vir addisionele wingerdbesproeiing dien. Dit is egter belangrik om te onthou dat die effekte van besproeiing met kelder afvalwater mootlik kumulatief kan wees en dat probleme moontlik eers na etlike jare na vore kan kom. Ander kultivars en veldkondisies mag ook lei tot ander resultate.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: There is a global demand for technologies to reduce ethanol levels in wine without compromising wine quality. While several chemical and physical methods have been developed to reduce ethanol in finished wine, the target of an industrially applicable biological solution has thus far not been met. Most attempted biological strategies have focused on developing new strains of the main fermentative organism, the yeast Saccharomyces cerevisiae. Gene modification approaches have primarily focused on partially redirecting yeast carbon metabolism away from ethanol production towards glycerol production. These techniques have met with some moderate success, thus the focus of the current study was to re-direct carbon flux towards trehalose production by moderate over-expression of the TPS1 gene. This gene encodes trehalose-6-phosphate synthase, which converts glucose 6-phosphate and UDPglucose to α,α-trehalose 6-phosphate. Previous data have shown that the overproduction of trehalose restricts hexokinase activity reducing the amount of glucose that enters glycolysis. Nevertheless, preliminary TPS1 over-expression studies using multiple copy plasmids have shown some promise, but also indicated significant negative impact on the general fermentation behaviour of strains. In order to reduce such negative impacts of excessive trehalose production, a new strategy consisting in increasing the expression of TPS1 only during specific growth phases and by a relatively minor degree was investigated. Our study employed a lowcopy number episomal vector to drive moderate over-expression of the TPS1 gene in the widely used industrial strain VIN13 at different stages during fermentation. The fermentations were performed in synthetic must with sugar levels representative of those found in real grape must. This, as well as the use of an industrial yeast strain, makes it easier to relate our results to real winemaking conditions. A reduction in fermentation capacity was observed for all transformed strains and controls. Expression profiles suggest that the DUT1 promoter certainly results in increased TPS1 expression (up to 40%) during early exponential growth phase compared to the wild type strain (VIN13). TPS1 expression under the control of the GIP2 promoter region showed increased expression levels during early stationary phase (up to 60%). Chemical analysis of the yeast and the must at the end after fermentation showed an increase in trehalose production =in line with the expression data of TPS1. Importantly, glycerol production was also slightly increased, but without affecting acetic acid levels for the transformed strains. Although ethanol yield is not significantly lower in the DUT1-TPDS1 strain, s statistically significantly lower ethanol yield is observed for over-expression under the GIP2 promotor. Increasing trehalose production during stationary phase appears therefore to be a more promising approach at lowering ethanol yield and redirecting flux away from ethanol production. This controlled, growth phase specific over expression suggests a unique approach of lowering ethanol yield while not impacting on the redox balance. / AFRIKAANSE OPSOMMING: Wêreldwyd is daar ‘n aanvraag na tegnologie wat die etanol vlakke in wyn kan verminder sonder om wyngehalte te benadeel. Terwyl verskeie chemiese en fisiese metodes ontwikkel is om etanol in die finale wynproduk te verminder, is die soeke na 'n industrieel gebaseerde biologiese oplossing tot dusver nie gevind nie. Meeste biologiese strategieë fokus op die ontwikkeling van nuwe rasse van die primêre fermentatiewe organisme, naamlik Saccharomyces cerevisiae. Geen modifikasie benaderings het hoofsaaklik gefokus op die gedeeltelike kanalisering van koolstof metabolisme weg van etanol produksie na gliserol produksie. Hierdie benadering is net matiglik suksesvol, dus is ons huidige fokus om koolstof te kanaliseer na trehalose produksie deur gematigde oor-uitdrukking van die TPS1 geen. Hierdie geen kodeer vir trehalose-6-fosfaat sintase, wat glukose-6-fosfaat en UDP-glukose omskakel na α, α-trehalose-6-fosfaat. Vorige data het getoon dat die oorproduksie van trehalose hexokinase aktiwiteit beperk en die hoeveelheid glukose wat glikolise binne gaan. Voorlopige TPS1 ooruitdrukking studies met behulp van multi-kopie plasmiede toon matige sukses, maar het ook ‘n negatiewe impak op die algemene fermentasie kapasiteit van die gis. Ten einde so 'n negatiewe impak van oormatige trehalose produksie te oorkom, is 'n nuwe strategie gevolg wat bestaan uit die verhoogde uitdrukking van die TPS1 geen slegs gedurende spesifieke groei fases met baie lae vlakke van oor-uitdrukking. Ons studie gebruik 'n lae-kopie episomale vektor met matige oor-uitdrukking van die TPS1 geen in die industriële ras VIN13 op verskillende stadiums tydens fermentasie. Die fermentasie is uitgevoer in sintetiese mos met suiker vlakke verteenwoordigend van dié van werklike wyn mos. Hierdie, sowel as die gebruik van 'n industriële gisras, maak dit makliker om ons resultate te vergelyk met regte wyn fermentasie kondisies. Verlaagde fermentasie kapasiteit is waargeneem vir alle getransformeerde stamme en hul kontroles. Geen uitdrukkings profiele dui op verhoogde TPS1 uitdrukking (tot 40%) onder beheer van die DUT1 promotor gedurende die vroeë eksponensiële groeifase wanneer vergelyk word met die wilde tiepe (VIN13). TPS1 uitdrukking onder die beheer van die GIP2 promotor het verhoogde uitdrukking van tot 60% gedurende die vroeë stasionêre fase. Chemiese analise van die gis aan die einde van fermentasie dui op ‘n toename in trehalose produksie wat korreleer met die uitdrukking profiele van TPS1. Gliserol produksie is ook effens verhoog, maar sonder ‘n toename in asynsuur vlakke vir die getransformeerde rasse. Alhoewel etanol opbrengs nie aansienlik laer vir die DUT1-TPS1 ras is nie, is etanol opbrengs vir die oor-uitdrukking onder beheer van die GIP2 promotor wel laer. Toenemende trehalose produksie gedurende stasionêre fase blyk dus 'n meer belowende benadering op die verlaging van etanol opbrengs en her-kanaliseering weg van etanol produksie. Hierdie benadering met die fokus op groeifase spesifieke oor-uitdrukking dui op 'n unieke strategie vir die verlaging van etanol opbrengs sonder om die redoks balans te beinvloed. / The NRF, IWBT and Stellenbosch University for funding

By exploring determinants of perceived wine quality and seeking possibilities to overcome Chinese wines’ negative COO effect, this paper aims to give insights to current research field about perceived quality and Country of Origin (COO) effect. Adopting an abductive approach, the researchers conducted qualitative semi-structured interviews separately with 11 respondents in different age, nationality and occupation. The results show that consumer perception on wine quality is influenced by four extrinsic cues (Country of Manufacturing, price, credible endorsements, brand) and four intrinsic cues (package, taste, aroma, wine legs). Hence, this paper conclude that it is possible for Chinse wine to improve its overall consumer perception by improving competence in other determinants of perceived wine quality.

Wine companies face two important challenges in their supply chain: the international shipping temperatures and their effect on the perceived quality of the wine and the optimization of the bottling schedule. The wine maker takes special care in producing the best quality product, which is then shipped to the importer/distributor or consumer, generally in non-refrigerated containers at the mercy of the prevailing environmental conditions. The contributions of this work is that it is the first to measure, for a significant period of time, the temperatures along the international wine supply chain and to link them to the specific supply chain processes. This is also the first work that analyzes the effect of shipping temperature on the perceived quality of the product by those who make the purchase decision for importers, restaurants and supermarkets. Results indicate that the wine is very likely to have been exposed to extreme temperatures during shipping. For white wines, tasters are able to detect differences in wines which have been exposed to shipping temperatures and show a preference towards them. For red wines, they are unable to detect differences. Our contribution to the second challenge was the development of a model that produces solutions for the wine bottling lot sizing and scheduling problem with sequence dependent setup times, in an adequate time-frame, which can be implemented by large wineries. We have developed a model and algorithm that produces fast, good and robust solutions for the winery lot sizing and scheduling problem with sequence dependent setup times. We implemented an effective decomposition algorithm that uses the structure of the problem, that can be applied to other families of sequence dependent scheduling and lot sizing problem. Results indicate that the model achieves reductions of 30\% in the total plan costs.