Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2018. / Renewable energy security for the future and better use of natural resources are key challenges that can be concurrently managed by a practical anaerobic co-digestion approach in the production of methane. For this study, co-digestion of cassava and winery waste was investigated for the production of biogas. Cassava biomass is a good substrate for biogas production due to its high carbohydrate yield per hectare (4.742 kg/carb) than most plants. Winery wastes constitute a lot of challenge in South Africa due to high amounts currently being dumped at landfills. Due to the chemical properties of the two substrates, it is envisaged that their co-digestion will produce more biogas than use of a single substrate. Biomethane potential (BMP) tests were carried out in a batch, mesophilic (37 °C±0.5) reactor using cassava and winery waste singly and in combination at a ratio of 1:1 and ran for 30 days. Biogas optimization was also evaluated. The optimal conditions for methane production from anaerobic co-digestion of cassava biomass and winery solid waste using response surface methodology (RSM). The effects of temperature, pH and co-substrate ratios on the methane yield were explored. A central composite design technique was used to set-up the anaerobic co-digestion experiment was determined. Once the optimized values were established, biogas production from co-digestion of cassava biomass with winery waste was investigated using a single-stage 5 L mesophilic batch digester and the microbial dynamics inside the digester during co-digestion of cassava and winery waste in the single-stage 5 L mesophilic batch digester. The samples were collected on days 1, 15 and 30 of the anaerobic digestion period and DNA extracted from them while 16sRNA bacterial sequencing was performed. The results for the BMP tests showed that cumulative methane yield for cassava, winery waste and in combination were 42, 21 and 38 mLCH4 respectively. It was concluded that biogas production from anaerobic digestion was dependent on many factors such as pH, substrate properties and the ratio of different feedstocks used during co-digestion. The results from the optimization study were pH 7, temperature of 35 °C±0.5 and co-digestion ratio of 70:30 cassava to winery waste. The maximum methane yield of 346.28 mLCH4/gVSadded was predicted by the quadratic model at the optimal temperature of 35 oC±0.5, pH of 7 and 70:30 ratio of cassava biomass to winery solid waste. Experimental results showed a close fit but higher methane yield (396 mLCH4/gVSadded) than predicted values as indicated by the coefficient of determination (R2) value of 0.9521. The response surface model proved successful in the optimization process of methane yield. The single-stage 5L mesophilic batch digester with a co-substrate ratio of 70:30 cassava to winery waste produced a total of 819.54 mL/gVS biogas with a 62 % methane content. The study of microbial community dynamics showed the presence of the bacteria that is responsible for each stage of anaerobic digestion. The study concluded that both winery waste and cassava substrates were favourable for biogas production and most underprivileged people in the rural areas with no access to electricity can produce & utilise it.

Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016. / Wines contain a number of phenolic compounds, belonging to non-flavonoid and flavonoid complexes. Phenolic compounds in wine are responsible for wine colour, astringency, and bitterness. Saccharomyces cerevisiae yeast is normally used in winemaking but it has been proved to decrease the phenolic content in wines. Current research on the use of non-Saccharomyces yeast in winemaking has produced better quality wines than S. cerevisiae yeast therefore improving the sensory profile of wine. This study evaluated effect of Torulaspora delbrueckii yeast on the phenolic content of experimental wines derived from Chenin blanc grapes. A reversed phase high-performance liquid chromatographic (RP-HPLC) method was used for the identification and quantitation of the phenolic compounds. The difference test method was used to determine the sensory attributes of wines. The data was subjected to analysis of variance to compare treatment differences between the wines and principal component analysis to establish possible correlation between the data sets. Furthermore, a gas chromatographic-flame ionization detection method (GC-FID) was used for the quantification of volatile compounds in the wines. In this work, wines made with T. delbrueckii strain M2/1 had high concentration of (+)-catechin, caffeic acid, ferulic acid and p-coumaric acid in all studied vintages. Wines made with VIN13 had higher concentrations of flavan-3-ols, compared to wines made with M2/1 and 654. In sensory evaluation, M2/1 wines were prominent in astringency and complexity. Yeast strain M2/1, also attributed to body and complexity of the wine. However, in this study no correlations were observed between the phenolic content and sensory attributes and vice versa. The quality of wine cannot be concluded by chemical or sensory analysis alone, but the data sets are complementary. Although the phenolic concentration of wines made with S. cerevisiae strain (VIN 13) and T. delbrueckii (M2/1) were similar in measured phenolic concentrations, they had different sensory attributes. Wines made during the 2013 vintage indicated the importance of the use of a strain with higher enzyme activity and high fermentation rate. There is minimal to no skin contact in white winemaking. Therefore, the use of a yeast strain with an increased enzyme activity can facilitate the extraction of phenolics from grape, resulting in wine with improved quality.

American Viticultural Areas (AVAs) are susceptible to small variations in climate and microclimates and are found within a narrow latitudinal range of prime climate conditions. These AVAs are geographically determined based on the best soil, climate, precipitation and temperature combinations for specific winegrape regions. As climate change continues to alter the local weather and the greater climate region of the Western United States, winegrape growing regions in Oregon are being affected. In an effort to determine what the pattern of change is, and compare previous studies of climate change using climate indices, a comparative study based in part on prior research was conducted. Using 800 meter resolution Parameter-elevation Regressions on Independent Slopes Model (PRISM) climate datasets, four individual climate indices were analyzed for statistical correlation with the climate data. These climate indices are: growing degree-days (GDD), the average growing season temperatures (GST), Huglin Index (HI) and the biologically effective degree-day (BEDD). Based on currently available data for this research, these climate indices were statistically analyzed during the years 2000 to 2010. A further avenue of research included a statistical analysis of the reported winegrape production, although this data was available only at an aggregated county-level. Results show that all four climate indices exhibit statistical significance, although the inclusion of the winegrape production data exhibited no statistical significance for many of the analyses, most likely due to subjective and aggregated data, few did result in significance with the climate indices. The research discussed here confirms the accuracy of the four climate indices and suggest that a longer time frame, coupled with less aggregated and subjective winegrape production data could produce interesting results in future research on the results of climate indices in winegrape growing regions.

No description available.

It is widely recognised that the tourism experience involves pre-visit anticipation, travel to and from the site and post-visit reminiscence or recollection, yet to date few studies have explored the link between these elements. Winery visitation presents an excellent opportunity to explore these phases of the travel experience as wine is present pre-visit, on-site and post-visit. In 1999 this study set out to explore these links by surveying visitors to 33 New Zealand wineries and then tracking their behaviour six to eight months post-visit via a postal survey. From an initial sample of 1,090, 636 follow-up surveys were distributed with 358 usable surveys returned. The on-site survey explored the pre-visit and on-site wine habits and winery visitation behaviour of respondents, while 97 semi-structured interviews were also undertaken in order to provide further detail on some aspects of the on-site visit. The follow-up survey included an exploration of the respondents� on-going purchasing and consumption of wine as well as experiential elements such as recollection of the visit, word-of-mouth behaviour and enduring levels of satisfaction. A number of a priori segmentation criteria drawn from wine consumer behaviour and wine tourism literature have been applied in the analysis of the data in order to provide a detailed discussion of the various elements of this multi-phased experience. Many regional differences were observed in the demographic profile of respondents, while the age profile of male and female visitors were also significantly different. This has dispelled the myth of a 'typical winery visitor' put forward by many early wine tourism researchers and highlights the need for detailed market analysis for wineries and wine regions. Pre-visit wine habits and winery visitation behaviour were influenced by gender, age/generation and country of origin. However, the most significant influence was between different levels of wine knowledge. This highlights the importance of wine education and interpretation, which was also identified as an important part of the winery visit by many respondents. Examination of the on-site experience identified important regional differences in the nature of the winery experience and lead to the coining of the term touristic terroir to describe the nuances of the regional experience. Almost half of the respondents made a post-visit purchase, while there were moderately high levels of enduring satisfaction and high levels of word-of-mouth behaviour. Post-visit purchases were primarily influenced by taste, but experiential elements of the visit (including sharing the wine or winery experience with others, memory of the visit and the service received) were also moderately influential. This study has provided an insight into wine tourism and the behaviour of the winery visitor. It is the first and, to date, only nationwide survey of winery visitors anywhere in the world and one of only a handful of tourism studies that have attempted to track the behaviour of respondents. It has identified important connections between the on-site experience, experiential aspects of the post-visit experience and the purchasing and consumption behaviour of winery visitors. It also provides a framework for the study of other areas of tourism including souvenir purchases, holiday photography, food and tourism and tourist behaviour more broadly.

Bibliography: leaves 138-158. / x, 158 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This study identified and investigated the properties, functions and patterns of accumulation of prominent berry proteins associated with white wine haze. Detailed analysis was conducted on two PR-like proteins of V. vinifera, VVPR-4a and VVTL1. In vitro fungal growth inhibition assays suggested that berry PR-like proteins may play an important role in plant defence, particularly against fungal attack. Results of this study also have future implications for controlling the ripening process of grapes. / Thesis (Ph.D.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1999

The yeast Saccharomyces cerevisiae is used in many industrial applications including beer brewing, bread making, and winemaking. Winemaking yeast strains have the ability to convert grape sugars into alcohol and other metabolites consistent with good wine. An exploratory comparative approach was undertaken to identify the genes and corresponding proteins that give wine yeast strains of S. cerevisiae their distinctive phenotype, with a focus on studying genes that provide tolerance to ethanol. / Thesis (Ph.D.)--School of Agriculture, Food and Wine, 2006.

The grape flavonoids include anthocyanins, tannins and flavonols, all of which contribute to grape and wine quality by influencing the colour and mouthfeel of red wine. These compounds are synthesized in different parts of the berry and during different stages of berry development. In addition, environmental and viticultural factors such as light exposure can also alter the flavonoid composition of grapes. An understanding of how synthesis of these compounds is coordinated, their relationship to wine quality and the influence of bunch light exposure on the flavonoid composition of grapes, could be used to improve fruit quality by enhanced viticultural management. The first part of this study sought to investigate the relationship between the different products of the flavonoid biosynthetic pathway (anthocyanins, flavonols and tannins), from two climatic regions (warm and cool) and determine their role in grape and wine quality. In collaboration with a major winery, whole Shiraz grapes were sampled at the weighbridge from a range of different vineyards from two climatic regions; warm (Riverland) and cool (McLaren Vale) in 2003 and 2004. A total of 80 grape samples were collected in each season and processed (i.e. 100 berries, separated into skin, seeds and juice, weighed and frozen). Anthocyanins and flavonols were measured, in triplicate, in skins by HPLC. Tannins were determined in the skins and seeds by two methods; phloroglucinol hydrolysis (HPLC) and protein precipitation (UV-VIS spectrophotometer). A comprehensive comparison of the two methods is discussed. In both years, the grapes from warm and cool climates formed two distinct data sets based on flavonoid composition. There was a correlation between anthocyanins and flavonols for both the warm and cool climate samples in both years, however those from the warm region had lower anthocyanin for a given level of flavonol. As expected, the level of tannin in the seeds was greater than in skin for all samples. In both years, there was a weak correlation between anthocyanin levels in the skin and skin tannins, but no relationship with seed tannins. These results suggest there is some co-ordination in the synthesis of anthocyanins, flavonols and skin tannins. Also, the two regions clearly separated based on yield and despite the weak correlations in both regions, the levels of total anthocyanins were inversely related to yield. In addition, there was no relationship with any of the flavonoids and grape quality, indicating the need for improvement in streaming fruit for quality using these flavonoid compounds. The second part of the study was to investigate the effect of bunch light exposure on flavonol synthesis and accumulation in Shiraz and Chardonnay grapes during development. Light-excluding boxes were applied to bunches at budburst. Boxes were removed at four sampling times; flowering, pre-veraison, veraison and harvest. At each sampling time, berry skins were sampled when the boxes were removed and then every second day (light induced), along with exposed controls for one week. Flavonol accumulation and flavonol synthase (VvFLS1) gene expression was determined by HPLC and Real Time-PCR (RT-PCR) respectively. As expected, for all four sampling times, flavonol accumulation and VvFLS1 expression in the boxed fruit was significantly less than bunches exposed to light. On removal of boxes at flowering, pre-veraison and veraison, flavonols accumulated to levels similar to that of the exposed control fruit over a period of 4-6 days. There was a significant increase in VvFLS1 expression 2 days after exposure to light in parallel with the accumulation of flavonols. At harvest, in Chardonnay, VvFLS1 expression peaked by day 4, while in Shiraz VvFLS1 expression increased linearly and was highest at day 6. In contrast to the results for the earlier sampling times, the total amount of flavonols accumulated at harvest was less than 50% of exposed controls in Chardonnay and Shiraz grapes. These results show that flavonols are able to be induced by bunch light exposure at different times during berry development, including times when flavonols are not normally being synthesised. This suggests bunch light exposure can override the developmental control of flavonol accumulation. To further investigate the light induced expression of VvFLS1 in grapevines the molecular mechanism of transcriptional control was explored. Using genomic walking PCR techniques, two Shiraz VvFLS1 promoter sequences were cloned and their sequences were analysed. These promoter sequences were ~800bp in length and were 99% identical. A putative MYB responsive element (MRE) and several light responsive elements (LRE) were identified in the promoter region of these genes. To functionally test the VvFLS1 promoter(s), a transient assay was developed in Chardonnay suspension cells. Cells were bombarded with constructs containing potential transcription factors and the VvFLS1 promoter(s), fused to a luciferase reporter vector. After 48hrs incubation in the dark, cells were harvested and luciferase activity measured as an indicator of VvFLS1 promoter activity. Of the different transcription factors tested with the VvFLS1 promoter(s) the highest luciferase activity was observed using AtMYB12 (a flavonol-specific regulator of AtFLS1 in Arabidopsis (Mehrtens et al. 2005). While this result shows activation of the VvFLS1 promoters by AtMYB12 and the development of a transient reporter assay for testing the VvFLS1 promoter(s) a grapevine transcription factor specific for VvFLS1 was sought. Two techniques were employed to identify potential transcription factor regulators of the VvFLS1 promoter(s). The first involved BLAST sequence search analysis in a grapevine expression (EST) database with AtMYB12 and the second involved using DNA microarray technology to identify candidate transcription factors that were up-regulated in light exposed Chardonnay cell suspension cultures. Thirteen potential transcription factors were identified and after correlative RT-PCR analysis (with VvFLS1 expression patterns) two candidates were selected for further isolation and characterisation. These results have made significant progress in unravelling the molecular mechanisms of regulation of the flavonol biosynthetic, however additional experiments are required to unravel the transcriptional control of flavonol biosynthesis. This investigation contributes to our knowledge of flavonoid synthesis in grapes; how it is coordinated, the relationship with wine quality, and the influence of light particularly on synthesis of flavonols. It also explores the molecular mechanisms of VvFLS1 control, through isolation of the VvFLS1 promoter and identification of potential transcription factors, which may regulate it. An understanding of the synthesis of flavonoids and how they may be coordinated, particularly in response to light, could be used to improve fruit quality by enhanced viticultural management. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1326767 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2008

Bibliography: leaves 138-158. This study identified and investigated the properties, functions and patterns of accumulation of prominent berry proteins associated with white wine haze. Detailed analysis was conducted on two PR-like proteins of V. vinifera, VVPR-4a and VVTL1. In vitro fungal growth inhibition assays suggested that berry PR-like proteins may play an important role in plant defence, particularly against fungal attack. Results of this study also have future implications for controlling the ripening process of grapes.

This research investigated the effects of Pediococcus spp. on Oregon Pinot noir wines. Pediococcus (P. parvulus (7), P. damnosus (1), P. inopinatus (1)) isolated from Oregon and Washington state wines demonstrated differences in their susceptibility to SO��� with some isolates growing well in model media at 0.4 mg/L molecular SO���. All isolates were all able to degrade p-coumaric acid to 4-vinyl phenol. The conversion of p-coumaric acid to 4-VP by pediococci resulted in accelerated production of 4-EP by B. bruxellensis in a model system. Growth of the pediococci isolates in Pinot noir wine resulted in a number of chemical and sensory changes occurring compared to the control. Very low concentrations of biogenic amines were measured in the wines with only wine inoculated with P. inopinatus OW-8 having greater than 5 mg/L. D-lactic acid production varied between isolates with OW-7 producing the highest concentration (264 mg/L). Diacetyl content of the wines also varied greatly. Some wines contained very low levels of diacetyl (< 0.5 mg/L) while others contained very high concentrations (> 15 mg/L) that were well above sensory threshold. Despite suggestions to the contrary in the literature, glycerol was not degraded by any of the isolates in this study. Color and polymeric pigment content of the wines also varied with wine inoculated with OW-7 containing 30% less polymeric pigment than the control. This may be related to acetaldehyde as a number of Pediococcus isolates, including OW-7, reduced the acetaldehyde content of the wine. Sensory analysis revealed differences in the aroma and mouthfeel of the wines compared to each other and to the control. In particular growth of some isolates produced wines with higher intensities of butter, plastic, and vegetal aromas while other also had lower perceived astringency. / Graduation date: 2013