Thesis (MTech (Civil Engineering))--Cape Peninsula University of Technology, 2017. / Currently in South Africa, most wastewater from small cellars is pH-adjusted and disposed of via land irrigation. This practice can lead to environmental degradation. There is a need for low cost, low maintenance solutions for the treatment of cellar effluent. Constructed wetlands provide such an option. However, the use of plants is problematic because winery effluent can be phytotoxic. After successful initial laboratory-scale experiments, an in-situ pilot scale biological sand filter (unplanted constructed wetland) system was designed, installed, and used to treat effluent from a small winery in the Western Cape, South Africa. The system is off-grid, totally self-regulating, and uses a modular approach which allows for the addition and subtraction of filter modules within the system to alter treatment capacity, retention time and/or rest filter modules. The system can be easily integrated into existing settling basins and/or retention ponds at small wineries. The biological sand filter was operational for 610 days, and showed promising results. The average chemical oxygen demand removal efficiency was 81% (range: 44-98%) with an average effluent of 324 mg/L, and an average flow rate of 413 L/day after the acclimation (start-up) period. The average hydraulic loading rate after the initial start-up period was 143 L/m3 sand day-1 (range: 67-222/m3 sand day-1), with an organic loading rate of 205 gCOD/m3 of sand day-1 (range: 83-338 gCOD/m3 sand day-1) which resulted in an organic removal rate of 164 gCOD/m3 of sand day-1. There was an average of 67% removal of total phenolics, thereby reducing the potential phytotoxicity of the effluent. In addition, there was a 1.6 times increase in calcium concentration, a 29% decrease in the average sodium adsorption ratio, and complete passive neutralisation of the acidic winery wastewater (final effluent pH range: 6.63 – 8.14. The findings of this study compare well with previous laboratory studies conducted with synthetic and authentic winery effluent. The system can potentially provide a low cost, energy efficient, low maintenance, sustainable means of treating cellar effluent at small wineries. Uptake of this technology may alleviate environmental degradation caused by irrigating land with inadequately treated effluent.

Wine grape pomace (WGP), the byproduct from winemaking, is a good source of polyphenols and dietary fibers, and may be utilized as antioxidant dietary fibers (ADF) for food applications. The objectives of this thesis research were to first determine the phenolic compounds, antioxidant and antimicrobial activities in red WGP under different drying processes for long-term storage, and to further evaluate the feasibility of using WGP as a functional food ingredient in yogurt and salad dressing for enhancing the nutritional value and improving storability of the products. Two types of WGP samples, pomace containing seeds and skins (P) and pomace with skins only (S) from Pinot Noir (PN) and Merlot (M) were studied. Samples were subjected to four different drying conditions: 40 °C conventional and vacuum oven, 25 °C ambient air and freeze dry. Total phenolic content (TPC, by Folin-Ciocalteu assay), anthocyanins (ACY, by pH differential method) and flavanols content (TFC, by vanillin assay) of the samples along with their antioxidant activity (DPPH radical scavenge method, RSA) and antibacterial activity (minimum inhibition concentration, MIC) were determined during 16 weeks of storage under vacuum condition at 15±2 °C. Meanwhile, dietary fiber profile was evaluated by using gravimetric-enzyme method. Results showed that dietary fiber contents of PN-P, PN-S, M-P and M-S were 57-63% d.m. with the majority of insoluble fraction. Freeze dried WGP retained the highest bioactive compounds with TPC 21.19-67.74 mg GAE/g d.m., ACY of 0.35-0.76 mg Mal-3-glu/g d.m., TFC of 30.16-106.61 mg CE/g d.m. and RSA of 22.01-37.46 mg AAE/g d.m., followed with ambient air dried samples. Overall, TPC, TFC and RSA were higher in PN than in M, and higher in pomace than in skins, while reverse results were observed in ACY. All samples lost significant amount of bioactive compounds during storage, in which ambient air and freeze dried samples had TPC reduction of 32-56% and 35-58%, respectively at the end of 16 weeks of storage. RSA in PN-P and M-P remained more than 50 mg TE/g d.m., meaning WGP still met the criteria of ADF definition after 16 weeks of storage. WGP extracts showed higher antibacterial efficiency against L. innocua than that of E. coli with MIC of 2, 7, 3 and 8% against L. innocua, and 3, 6, 4 and 9% against E. coli for PN-P, PN-S, M-P and M-S samples, respectively. This study demonstrated that Pinot Noir and Merlot pomace are good sources of ADF even after 16 weeks of storage at 15 °C and vacuum condition. Due to the highest antioxidant activity (RSA 37.46 mg AAE/g) and dietary fiber content (61%), PN-P was selected as ADF to be fortified in yogurt and salad dressing. Three types of WGP: whole powder (WP), liquid extract (LE) and freeze dried extract (FDE) with different concentrations were incorporated into yogurt (Y), Italian (I) and Thousand Island (T) salad dressings. TPC, RSA and dietary fiber content, major quality attributes including pH and peroxide value (PV) during the shelf life and consumer acceptance of fortified products were evaluated. The highest ADF were obtained in 3% WP-Y, 1% WP-I and 2% WP-T samples with the dietary fiber contents of 1.98%, 2.12% and 1.83% and RSA of 935.78, 585.60 and 706.67 mg AAE/kg, respectively. WP fortified products had more dietary fiber content than that of LE and FDE fortified ones because of the insoluble fractions. The pH dropped from 4.52 to 4.32 for 3% WP-Y during three weeks of storage at 4 °C, but remained stable in WGP-I and WGP-T samples after four weeks of storage at 4 °C. Adding WGP resulted in 35-65% reduction of PV in all samples compared to the control. In WGP-Y, the viscosity increased, but syneresis and lactic acid percentage were stable during storage. The 1%WP-Y, 0.5%WP-I and 1%WP-T samples were mostly liked by consumers. Study demonstrated that WGP can be used as a functional food ingredient for enhancing nutraceutical content and extending shelf-life of the food products. This study provided important information about the economically feasible drying methods for retaining the bioactive compounds in WGP during processing and storage and also suggested that WGP can be utilized as antioxidant dietary fiber to be fortified in consumer products to promote nutritional benefit and extend product shelf-life. / Graduation date: 2013

No description available.

Thesis (MBA (Business Management))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Distell Group limited is South Africa's leading producer and marketer of fine wines, spirits and ready-to-drinks. The wine division has been confronted with limitations on pressing capacity for a number of years. Sales of Distell wine brands are projected to grow substantially, in particular in the premium and super premium categories. Therefore a need for increase sUstainable supply of wine was created. The objective of this study was to increase the throughput in Distell wineries significantly, without or with minimal cash investment, by applying the principles of a combined supply chain strategy. To achieve this, the study needed to allow for the analysis of various scenarios, and indicate where the various constraints were within the process. Theory of constraint, which is a management philosophy aiming to continually achieve more of the system's goal was applied to the Distell situation. The focus points were to create value for the organisation, with collaboration between grape farmers and the wineries. It was necessary to follow a process of data capturing, and the data obtained from the various sources in 2008 was combined into one database to develop a capacity evaluation model. There is no doubt that the Distell wineries as a group, improved their efficiency over the last number of years, with effective management of the individual wineries. There is however enough evidence to support the change to a combined supply chain strategy, which could unlock more total benefits than the individual management. It is clear from the findings in this study that not all the current available capacity is fully utilised. This study found that the white process in Distell was working at a higher than required rate of the set capacity targets, and would need substantial capital investment to increase throughput. The red process indicated opportunities for increase throughput in the total system. It is possible to increase total throughput and maintain quality for Distell wineries. / AFRIKAANSE OPSOMMING: Distell is een van Suid Afrika se grootste produseerders en bemarkers van hoe gehalte wyn, spiritus produkte en alkoholiese drankies. Die wynkelder omgewing ervaar al vir 'n geruime tyd kapasiteit tekorte. Die vraag na Distell wynhandelsmerke verwag om 'n konstante groei te toon oor die volgende paar jare, veral op die premium en super premium katogoriee. Oit veroorsaak 'n groeiende behoefte vir die volhoubare voorsiening van wyn, binne die maatskapy. Die doel van die studie was om produksie te verhoog binne die Distell kelders, met min of geen kapitale beleging, deur 'n holistiese strategie te volg ten opsigte van die bestuur van die waardeketting. Die studie het verskeie alternatiewe ondersoek met die doe I om die beperkings in die proses te identifiseer en te ontleed. Die bestuurs filosofie 'Theory of constraint' is toegepas, waar daar gestreef word om meer te bereik, van die mikpunt wat ge5tel is vir 'n spesifieke proses. Die hoofdoel van die maatskapy was om waarde te skep, deur samewerking tussen druiwe produsente en die verskiliende Distell kelders. Die nodige data vir die ontleding van die beskikbare kapasiteit is verkry gedurende die 2008 seisoen. Die inligting is saamgevoeg in een data-stel, en 'n kapasiteitsmodel is ontwikkel. Daar is geen twyfel dat Disteli kelders as 'n groep hul doeltreffenheid verbeter het, deur die individueele prosesse te bestuur. Die studie lewer egter genoeg bewyse dat daar 'n groter potensieeHe voordeel is, indien die proses op 'n holistiese waardekettingstrategie bestuur sal word. Die studie lewer bewyse dat die huidige beskikbare kapasiteit nog nie optimaal benut word nie. Die verwerking van druiwe in die witwyn proses vind plaas teen 'n hoer kapasiteitsbenutting as wat waarvoor beplan was. Om enige verdere witdruiwe volumes te hanteer, sal tot groot kapitale besteding lei. Die rooiwyn proses wys daar is ruimte vir verbetering, sonder groot kapitale spandering. Die studie het gevind dat die totale proses meer volumes rooidruiwe kan hanteer, en steeds voldoen aan die nodige kwaliteit vereistes.

Thesis (MBA)--Stellenbosch University, 2012. / Almost every geographical wine producing area has a generic marketing organisation in the form of a wine route organisation or similar organisation that aspires to create a favourable perception of their area in the minds of wine consumers. In their efforts to try and escape the growing commoditising of wines, wine producers recently intensified their efforts to differentiate themselves from other offers by increasingly certifying more wine as wine from a specific geographical area, launching competitions that embrace terroir as the defining factor for quality and increasing the number of demarcated areas. It was the purpose of this study to examine whether the South African consumer assigns a high degree of relevance to the certification of origin as an influencing factor when purchasing wine. As a starting point, a literature study was conducted to establish the current state of knowledge regarding the relevance of certification of origin of wine in wine marketing. The literature review also provided the framework for designing a survey conducted among South African wine consumers. The data gathered via an online questionnaire was analysed by employing both descriptive and inferential statistical methods. The analysis showed that certification of origin of wine plays a secondary role in influencing consumers when faced with a purchasing decision on its own. However, as part of the regional composite variable, which consists of variety, region and wine style, it plays a major role in influencing consumers (McCutcheon, Bruwer & Li, 2009: 229). In accordance with other studies conducted among South African wine consumers (Von Arnim, 2008: 58), the specific wine variety emerged as the most important factor influencing consumers. It was also found that consumers with a high involvement and interest in wine assign a higher degree of relevance to certification of origin of wine than consumers with a low involvement. The findings of this research report are based on respondents who mainly reside within the Western Cape and the demographic profile of respondents shows that mostly male respondents completed the online questionnaire. The findings are therefore tentative due to the geographical and demographical limitations. This research report is of value to academic researchers, wine marketing professionals and generic marketing organisations such as wine route organisations.

Thesis (MSc (Wine Biotechnology))--University of Stellenbosch, 2006. / The production of premium quality wine is dependant on excellent management of the total wine production value chain. To achieve this we need rapid and reliable analytical tools. Over the last decade Fourier transform infrared (FT-IR) spectroscopy has made a significant contribution to wine research and in the last five years South African institutions have also exploited the use of this technology not only for research, but also in industrial cellars. The FT-IR apparatus is equipped with global calibrations and therefore we first investigated the validity of these for South African conditions. To achieve this new calibration sets for pH, titratable acidity and °Brix were made and compared to the global calibrations with statistical methods. Results obtained between the °Brix calibrations displayed high correlation and the global calibration can therefore be implemented. However, the new TA calibration was more accurate than the global calibration. Results were inconclusive for the new pH calibration sample set and therefore needs to be enlarged before it can be validated as the possibility of being more accurate exists. It was concluded that FT-IR spectroscopy in the simultaneous measurement for °Brix, pH and TA in grape must showed potential for accurate analysis and quality control purposes in an industrial cellar. Rapid analysis of these parameters will lead to higher throughput of grape must samples in the laboratory as well as adhering to good laboratory practices by validation. The importance of correct sample preparation in the laboratory was illustrated when using FT-IR spectroscopy for one-step analysis and adjustments to global calibrations. Results obtained showed that grape parameters such as °Brix, nitrogen content were not influenced by the two sample preparation methods (hand pressed vs. homogenised), but pH, TA, colour index, anthocyanins and polyphenols were influenced. Important key factors were identified in the quality control chain from vineyard to the cellar. Numerous grape loads had an increase in microbial populations after harvesting the vineyard and transport to the weighbridge. Transport is critical especially for the vineyards in the Lutzville area (had the highest yeast population), which are situated the furthest from the cellar. Sauvignon blanc had the highest acetic acid bacteria and lactic acid bacteria populations compared to the other cultivars. Gluconic acid, glycerol and arabitol was highly correlated to each other. High populations of acetic acid bacteria and lactic acid bacteria also had high levels of gluconic acid and 2,3-butanediol in the grape juice. Meso-inositol differed significantly between the vineyard and weighbridge and it had a high standard deviation compared to the mean value of all the samples between the vineyard and weighbridge. Temperature of grape loads delivered to the cellar ranged from 14 to 36ºC, which had a major impact on the grape quality and the resultant wine. It can be concluded for this study that management of the total value chain is of critical importance to ensure that A-grade grapes results in good quality wine that merits the effort of the grape producer.

Thesis (MScAgric) -- Stellenbosch University, 1944. / INLEIDING: Gedurende die afgelope twee dekades, terwyl die wereld die ekonomiese terugslag van die Eerste Wereld-Oorlog in sy volle felheid beleef het, het prysbeheer in verskeie lande meer en meer op die voorgrond getree. Die feit dat na prysbeheer so gretiglik gegryp word, selfs wanneer demokratiese lande in 'n ekonomiese wurggreep worstel, wys op die feit dat prysbeheer beskou ,is as 'n noodhulpmaatreel. Hoe ernstiger die ekonomiese nood, hoe meer algemeen is prysbeheer.

Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The present study was initiated by the wine industry of South Africa to overcome the lack of available information on the flavor and aroma of South African wines. The aim was to develop new analytical methods and improve existing ones for the analysis of volatile compounds in the South African wines. Initially a new analytical method based on stir bar sorptive extraction (SBSE) in the headspace mode for the analysis of 37 pre-selected volatile compounds was developed and validated. Consequently, the method was improved by making important modifications and increasing the number of compounds analyzed to 39. This method was successfully applied to a large number of Pinotage wines of vintages 2005 and 2006. The quantitative data of these wines were subjected to chemometric analysis in order to investigate possible co- /variances. A clear distinction was observed between the two vintages, where the 2005 wines were more characterized by wood-related compounds and the 2006 wines by the fermentation compounds. The developed method was further applied to other cultivars of vintage 2005, including two white (Sauvignon Blanc and Chardonnay) and three red (Shiraz, Cabernet Sauvignon and Merlot) cultivars. In a similar fashion, the quantitative data of the six cultivars of vintage of 2005 were analysed by chemometric methods. Significant differences were observed between the two white cultivars and among the four red cultivars. It was shown that among these cultivars, the major role-players were the wood and fermentation related volatiles. A striking observation was the confirmation of the unique character of the Pinotage wines compared to the other red cultivars, mainly influenced by the high level of isoamyl acetate and low level of isoamyl alcohol, the former being categorized as a varietal compound for Pinotage expressed by a fruity (banana) odor. In addition, advanced chromatographic technology in the form of comprehensive twodimensional gas chromatography (GC × GC) coupled to time-of-flight mass spectrometry (TOFMS) was investigated for the detailed analysis of volatile compounds in young South African wines. This work focused primarily on Pinotage wines. In the first instance, solid phase micro extraction (SPME) in the headspace mode in combination with GC × GC-TOFMS was used. Due to the high resolution and large peak capacity of GC × GC, more than 200 compounds previously reported as wine components were identified. These compounds were dominated by the highly volatile and less polar compounds, mainly due to the characteristics of SPME. In an attempt to further extend these results, another selective extraction method, solid phase extraction (SPE) was used in combination with GC × GC-TOFMS analysis. Using this technique, more than 275 compounds, most of them unidentified using the previous method, were detected. These groups of compounds include volatile phenols, lactones as well as mostly aromatic esters and norisoprenoids, which can potentially influence the aroma and flavor of wine. The techniques developed as part of this study have extended our knowledge of the volatile composition of South African wines. / AFRIKAANSE OPSOMMING: Hierdie studie is geïnisieer deur die wyn industrie van Suid-Afrika om die tekort aan beskikbare inligting aangaande wyn aroma van Suid-Afrikaanse wyne te oorkom. Die doel was om nuwe analitiese metodes te ontwikkel en die huidige metodes te verbeter vir die analise van vlugtige verbindings in Suid-Afrikaanse wyne. Oorspronklik is ʼn nuwe analitiese metode ontwikkel en gevalideer gebaseer is op ‘stir bar sorptive extraction’ (SBSE) in die gas fase vir die analise van 37 vooraf geselekteerde vlugtige verbindings. Die metode is verbeter deur belangrike modifikasies aan te bring en die hoeveelheid verbindings wat analiseer word te vermeerder na 39. Hierdie metode is suksesvol aangewend op ʼn groot hoeveelheid Pinotage wyne van oesjare 2005 en 2006. Die kwantitatiewe data van hierdie wyne is onderwerp aan verskillende chemometriese analises om moontlike ko-/variasies te ondersoek. ʼn Duidelike onderskeid is opgemerk tussen die twee oesjare, waar die 2005 wyne gekarakteriseer is deur hout-verwante verbindings en die 2006 wyne weer meer deur fermentasie verbindings. Die verbeterde metode is verder aangewend vir analiese van ander kultivars van oesjare 2005, wat twee wit (Sauvignon Blanc en Chardonnay) en drie rooies (Shiraz, Cabernet Sauvignon en Merlot) ingesluit het. Die kwantitatiewe data van die ses kultivars van oesjaar 2005 is op ʼn soortgelyke wyse geanaliseer deur verskillende chemometriese metodes te gebruik. Beduidende verskille is opgemerk tussen die twee wit kultivars en tussen die vier rooi kultivars. Die hoof rolspelers tussen die ses kultivars was weereens die verbindings wat ʼn hout en fermentasie aard het. Die unieke karakter van die Pinotage wyne in vergelyking met die ander rooi kultivars was opvallend. Hierdie wyn word gekarakteriseer deur hoë vlakke van isoamiel asetaat en lae vlakke van isoamiel alkohol, waar eersgenoemde gekatogiseer word as ʼn verbinding wat ʼn vrugte (piesang) geur in Pinotage uitdruk. Verder is gevorderde chromatografiese tegnologie in die vorm van ‘comprehensive two-dimentional gas chromatography’ (GC x GC) gekoppel met ‘time-of-flight mass spectroscopy’ (TOFMS) ondersoek vir die analiese van vlugtige verbindings in jong Suid-Afrikaanse wyne. Hierdie werk het hoofsaaklik op Pinotage wyne gefokus. Eerstens is ‘solid phase micro extraction’ (SPME) in die gas fase gekombineer met GC x GC-TOFMS. As gevolg van die hoë resolusie en groot piek kapasiteit van GC x GC is meer as 200 verbindings wat voorheen gerapporteer is as wyn komponente geïdentifiseer. Hierdie verbindings is gedomineer deur hoë vlugtige polêre verbindings, hoofsaaklik as gevolg van die karaktersitieke van SPME..In ʼn poging om die metode verder te verbeter is ʼn selektiewe ekstraksie metode naamlik ‘solid phase extraction’ (SPE) in kombinasie met GC x GC-TOFMS gebruik. Met hierdie tegniek is meer as 275 verbindings geïdentifiseer, waarvan die meeste nie met die vorige metode waargeneem is nie. Hierdie verbindings sluit vlugtige fenole, laktone en meestal aromatiese esters en norisoprenoïdes in, wat moontlik die reuk en smaak van wyn kan beïnvloed. Die metodes ontwikkel gedurende die studie het nuwe informasie verskaf aangaande die vlugtige komponente teenwoordig in Suid Afrikaanse wyne.

Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2008. / The main goal of this study was the development of new technologies based on modern analytical techniques for analysis of volatiles in wines. Due to the exponential growth of the wine industry and consumer demands for an enjoyable, safe-to-consume, and high quality product, the need for arose for methodologies aiding the understanding of wine better arose. Chemical analysis is a valuable way of studying the composition of wine in depth. Very sophisticated instrumentation is available nowadays but almost always the sample needs to be cleaned up or concentrated before such analysis. This study investigates the use of stir bar sorptive extraction (SBSE) as such a technique. It is shown that SBSE combined with gas chromatography-mass spectrometry (GC-MS) is extremely suited for a wide number of analyses and during the course of the study the technique was applied for troublesome analytical challenges in various beverages and foodstuffs. The study focuses on the development of a screening technique for volatiles in wine using SBSE and the application of the data to various chemometrical techniques for classification purposes. A second part of the study shows the applicability of SBSE for extraction of pesticides, contaminants and preservatives from wine, water, lemon flavoured beverages and yoghurt. The method is also elaborated upon by development of faster analysis methods for wine and beer and the investigation of using SBSE for headspace sampling of wine. In all the applications, SBSE technology was shown to be sensitive, repeatable, robust and very simple to use.

Thesis (MSc Food Sc (Food Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This study focussed on the sensory effects of the main volatile compounds produced by Brettanomyces yeast causing spoilage in wine. This research firstly aimed to determine the detection thresholds of eight Brett-related spoilage compounds in wine. The second aim was to determine the sensory effect of the four most important Brett-related compounds when present individually in wine. The third aim was to determine the sensory effects of these four compounds when present in wine in a range of combinations, and to further investigate their effect on consumer liking. Finally, this project aimed to investigate the incidence of these compounds in a small range of South African wines. The sensory detection thresholds of 4-ethylphenol, 4-ethylguaiacol, 4-ethylcatechol, 4- vinylphenol, 4-vinylguaiacol, isovaleric acid, isobutyric acid and acetic acid were determined. Apart from 4-ethylcatechol, these values generally agreed well with recent literature where values determined in wine are available. However, the discrepancies highlighted the importance of the effect of the medium (wine) when determining sensory detection thresholds. The use of the median as alternative calculation method was also investigated, and it was found that this method gives more insightful results than the standard American Society of Testing Materials (ASTM E679-04) method. Four compounds, namely 4-ethylphenol, 4-ethylguaiacol, 4-ethylcatechol and isovaleric acid were profiled individually in wine using a trained sensory panel. It was found that all four compounds caused a suppression of the natural berry-like character in the wine, which induced a sick-sweet character. 4-ethylphenol contributed Elastoplast™ and leather aromas in the wine, both of which are commonly associated with Brettanomyces taint. 4-ethylguaiacol added a medicinal aroma to the wine, and 4-ethylcatechol and isovaleric acid were responsible for savoury and pungent aromas, respectively. 4-ethylphenol, 4-ethylguaiacol, 4-ethylcatechol and isovaleric acid were also profiled in combination according to the central composite design. Several univariate and multivariate methods were applied to the dataset obtained. PARAFAC, a multiway method not widely utilized regarding sensory data, was applied to the data, the results of which were complementary to those obtained during univariate and multivariate analyses. It was found that there is a great deal of interaction between the four compounds profiled in terms of sensory effects. The most notable was the Elastoplast™ attribute, the intensity of which was affected by all four compounds. The pungent attribute was also affected by the 4-ethylphenol concentration. Consumer analysis revealed that some of the samples spiked with Brettanomyces-spoilage compounds were preferred to the unspiked (control sample). However, no further relationship could be found between consumer liking and either chemical composition or sensory profile. It is therefore speculated that consumer liking of Brettanomyces infected wine is driven by more complex sensory or socio-demographic factors. Finally, the concentration of 4-ethylphenol, 4-ethylguaiacol, 4-ethylcatechol, 4-vinylphenol, 4- vinylguaiacol, isovaleric acid, isobutyric acid and acetic acid was determined in a small set of South African wines, selected to contain a high proportion of wines spoiled by Brettanomyces. Significant correlations were found between 4-ethylphenol and 4-ethylguaiacol, as well as 4- ethylphenol and isovaleric acid. However, no correlation could be found between 4-ethylphenol and 4-ethylcatechol. It is speculated that this lack of relationship is due to the different precursor profiles present in the analysed wines. This study paved the way for future investigations on the sensory effects of Brettanomyces spoilage in Pinotage red wine. / AFRIKAANSE OPSOMMING: Hierdie studie het gefokus op die sensoriese invloed van die belangrikste vlugtige komponente wat deur die Brettanomyces gis geproduseer word en bederf veroorsaak in wyn. Eerstens is gefokus op die bepaling van die deteksiedrempelwaardes van agt Brett-verwante bederwende komponente. Die tweede doelwit was om die sensoriese invloed van vier van die mees belangrike Brett-komponente te bepaal wanneer hulle individueel in wyn voorkom. Die derde doelwit was om die sensoriese invloed van hierdie vier komponente te bepaal wanneer hulle in verskillende kombinasies in wyn voorkom, asook die effek daarvan op verbruikervoorkeur. Laastens is gepoog om die voorkoms van hierdie komponente in ‘n klein seleksie van Suid- Afrikaanse wyne te bepaal. Die sensoriese deteksiedrempelwaardes vir 4-etielfenol, 4-etielguaiacol, 4-etielcatechol, 4- vinielfenol, 4-vinielguaiacol, isovaleraatsuur, isobuteraatsuur en asynsuur is bepaal. Met die uitsondering van 4-etielcatechol het die waardes oor die algemeen goed ooreengestem met waardes wat onlangs in die wetenskaplike literatuur gepubliseer is. Die uitsonderings het egter die belangrikheid van die medium (wyn) gedurende die bepaling van sensoriese deteksiedrempelwaardes uitgelig. Die gebruik van die mediaan as ‘n alternatiewe berekeningsmetode is ook ondersoek en daar is gevind dat hierdie metode meer insiggewende resultate lewer as die standaard American Society of Testing Materials (ASTM E679-04) metode. Vier komponente naamlik 4-etielfenol, 4-etielguaiacol, 4-etielcatechol en isovaleraatsuur is individueel in wyn geprofileer met behulp van ‘n opgeleide sensoriese paneel. Daar is gevind dat al vier die komponente die natuurlike bessiekarakter in die wyn onderdruk terwyl dit aanleiding gee tot ‘n onnatuurlike soet karakter. 4-etielfenol is gekenmerk aan Elastoplast™ en leeragtige aromas in die wyn en beide van hulle word algemeen geassosieer met Brettanomyces bederf. 4-etielguaiacol het ‘n medisinale aroma tot die wyn toegevoeg en 4- etielcatechol en isovaleraatsuur het respektiewelik souterige (“savoury”) en sterk (“pungent”) aromas tot gevolg gehad. 4-etielfenol, 4-etielguaiacol, 4-etielcatechol en isovaleraatsuur is ook in verskeie kombinasies geprofileer volgens die sentrale saamgestelde ontwerp (“central composite design”). Verskeie enkelveranderlike en meerveranderlike statistiese analisemetodes is ook op die datastel uitgevoer. PARAFAC, ‘n meerrigtingsmetode wat nie normaalweg vir sensoriese analise data gebruik word nie, is ook uitgevoer op die data en die resultate was komplimentêr tot die van die enkelveranderlike en meerveranderlike analisemetodes. Daar is gevind dat, met betrekking tot sensoriese effekte, daar noemenswaardige interaksie tussen die vier komponente plaasvind. Die mees opmerklike hiervan was die Elastoplast™ aroma, waarvan die intensiteit deur al vier die ander komponente geaffekteer is. Verder is die sterk (“pungent”) aroma beïnvloed deur die 4-etielfenol konsentrasie. Verbruikersvoorkeur-analise het aangedui dat sommige van die monsters waarby Brettanomyces bederwende komponente gevoeg is, verkies word bó die kontrole-wyn. Daar kon egter geen verdere verband gevind word tussen die verbruiker se voorkeur en, nog die chemise komposisie of sensoriese profiele, van die wyn nie. Daar kan dus gespekuleer word dat verbruiker voorkeur van Brettanomyces bederfde wyn gedryf word deur meer komplekse en sosio-demografiese faktore. Laastens is die konsentrasies van 4-etielfenol, 4-etielguaiacol, 4-etielcatechol, 4-vinielfenol, 4- vinielguaiacol, isovaleraatsuur, isobuteraatsuur en asynsuur in ‘n seleksie van Suid-Afrikaanse wyne bepaal. Dié wyne is spesifiek so gekies sodat ‘n aansienlike aantal van hulle met Brettanomyces bederf was. Betekenisvolle korrelasies is gevind tussen 4-etielfenol and 4- etielguaiacol, sowel as 4-etielfenol en isovaleraatsuur. Daar is egter geen korrelasie tussen 4- etielfenol and 4-etielcatechol gevind nie. Daar word vermoed dat hierdie gebrek aan korrelasie te wyte is aan die voorloperkomponent profiele teenwoordig in die wyne. Hierdie studie het die weg gebaan vir verdere ondersoeke na die sensoriese effekte van Brettanomyces bederf in Pinotage rooi wyn.