No description available.

Thesis (PhD (Medicine. Internal Medicine))--Stellenbosch University, 2008. / Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease in Western countries, extending from steatosis (FLD) to steatohepatitis (NASH). Differentiation between NASH and nonprogressive NAFLD is difficult on clinical grounds therefore a need exists to identify reliable biomarkers of disease progression. The aims of the study were 1) to describe the disease profile of NAFLD/NASH in South African patients of the Western Cape, 2) to investigate the metabolic derangements associated with this condition, including insulin resistance, lipid abnormalities and liver fibrogenesis, and 3) to assess the possible involvement of candidate genes in relation to the disease phenotype in the patient cohort. A total of 233 patients (73% female) were enrolled in this study, consisting of 69% Cape Coloured, 25% Caucasian, 5% Black and 1% Asian individuals. All subjects were obese or overweight based on the assessment of body mass index (BMI). Screening for NAFLD identified 182 patients (87%) with ultrasonographical evidence of fatty infiltration and/or hepatomegaly. Liver biopsies were performed on patients with persistently abnormal liver functions and/or hepatomegaly. NAFLD was confirmed histologically in 111 patients of whom 36% had NASH and 17% advanced liver fibrosis. None of the Black patients had advanced fibrosis.

M. Tech. Marketing / The primary objective of this study was to investigate the role that advertising plays in alcoholic beverage consumption patterns of the youth of Tshwane. Several secondary research objectives were set which include: examining the overall alcoholic beverage consumption of young people, the alcoholic beverage types and brands consumed, exposure to alcoholic beverage brand advertising, exposure to media in which alcoholic beverages are advertised, differences between males and females with regards to their consumption of alcoholic beverages as well as the alcoholic beverage types they consume, the relationship between age and alcoholic beverage consumption, income and alcoholic beverage consumption and other factors that can influence young people to consume alcoholic beverages.

Thesis (M.A.)--Kent State University, 2009. / Title from PDF t.p. (viewed Oct. 6, 2009) Advisor: C. Andre Christie-Mizell. Keywords: Substance Use; Alcohol; Race; Gender; Life Course Transitions Includes bibliographical references (p. 38-49)

Les maladies alcooliques du foie (MAF) sont responsables de 3,8% de la mortalité mondiale et restent une cause majeure de mortalité par maladies hépatiques, plus importante que l’hépatite C. Malgré le fardeau qu’elles représentent, tant sur le plan de la morbi-mortalité que sur le plan économique, il n’existe que très peu d’options thérapeutiques hormis l’abstinence et la transplantation hépatique. Une meilleure compréhension de la pathophysiologie et des facteurs impliqués dans les MAF permettrait d’identifier de nouvelles cibles thérapeutiques afin d’améliorer la prise en charge et le pronostic des patients.Il est largement admis que les patients souffrant de MAF présentent une dérégulation de leur réponse immunitaire. A l’état de base, il existe déjà une hyper-activation de leurs monocytes circulants et une élévation de leurs taux plasmatiques de cytokines pro-inflammatoires, dont le tumor necrosis factor-α (TNF-α). Lors d’une stimulation, la réponse inflammatoire des patients avec une MAF est exacerbée, les taux de TNF-α augmentent rapidement. Cet état, dont tous les mécanismes ne sont pas encore élucidés, est associé avec la sévérité et la mortalité de la MAF, ainsi qu’avec la survenue de complications de la cirrhose. Identifier les facteurs qui sous-tendent à cette réponse inflammatoire excessive et délétère aiderait probablement à mieux la réguler. Les patients atteints de MAF présentent de manière très fréquente un état de dénutrition qui est également associé au développement de complications et à la mortalité de la cirrhose. Les études de supplémentation nutritionnelle, dont les résultats sont controversés, se sont portées principalement sur le versant protéino-calorique des carences, alors que les patients souffrant de MAF présentent aussi des déficiences spécifiques en micro-nutriments, notamment en vitamines A et D, dont la signification pathophysiologique n’a jamais été étudiée. En effet, les vitamines A et D possèdent, en plus de leurs effets classiquement décrits, des effets immuno-modulateurs, anti-inflammatoires, anti-TNF-α et anti-fibrosants. Les carences en vitamine A et en vitamine D, ou en leurs métabolites actifs, l’acide all-trans rétinoïque (ATRA) et la 1α,25-dihydroxyvitamine D (1,25(OH)2D), pourraient donc être impliquées dans l’hyper-réponse inflammatoire délétère et dans la fibrose présentes dans les MAF. Dans un premier temps, nous avons étudié l’association entre les taux plasmatiques des vitamines A, D et d’ATRA, et la sévérité et la mortalité des MAF. Nous avons confirmé l’existence de déficiences en ces micro-nutriments chez les patients souffrant de MAF et nous avons montré l’association significative de ces carences avec la sévérité de la maladie, évaluée par les scores de MELD et de Child-Pugh, ainsi qu’avec la mortalité. Ces observations épidémiologiques très intéressantes ne permettent, cependant, pas de déterminer le rôle biologique potentiel des carences en vitamines A et D dans le développement et la progression des lésions hépatiques liées à l’alcool. En effet, le foie étant l’organe principal de stockage de la vitamine A et le lieu de la première hydroxylation de la vitamine D, les carences pourraient aussi bien être la conséquence de l’insuffisance hépatique et donc, un marqueur de sévérité, qu’une cause aux lésions, et donc une cible thérapeutique potentielle. Afin de déterminer l’existence d’un lien causal entre déficience et maladie hépatique, nous avons élaboré des expérimentations in vitro sur des cellules de patients et in vivo chez la souris. Nous montrons que les supplémentations in vitro en ATRA ou en 1,25(OH)2D modifient la réponse inflammatoire exacerbée des lymphomonocytes circulants (PBMC :peripheral blood mononuclear cells) de patients avec MAF. Elles diminuent l’expression et la production de TNF-α et augmentent celle de l’interleukine-10 (IL-10), cytokine anti-inflammatoire, en ce qui concerne l’ATRA. L’action de ce dernier est pré-transcriptionnelle puisqu’il agit sur l’expression de TNF-α, et semble être dépendante de son récepteur à l’acide rétinoïque de type RAR. En effet, l’ATRA agit via sa liaison à deux types de récepteurs, le RAR et le RXR, récepteur rétinoïque X. Nos données montrent que l’utilisation d’un agoniste RAR reproduit les mêmes effets que l’ATRA, à l’inverse de l’utilisation d’un agoniste RXR. In vivo, dans un modèle murin de MAF, nous montrons que la supplémentation orale en 1,25(OH)2D est capable de diminuer l’expression intra-hépatique de TNF-α qui est augmentée par le régime alcoolisé. Nos résultats montrent donc que dans le contexte des lésions hépatiques liées à l’alcool, les supplémentations en métabolites actifs des vitamines A et D, in vitro, sur des cellules de patients, et in vivo, dans le modèle Lieber-DeCarli, ont un effet inhibiteur sur le TNF-α circulant et intra-hépatique. En parallèle à ces données de supplémentation, nous montrons que la carence en vitamine A chez des souris s’accompagne d’une augmentation de l’activation et de la fonction de leurs macrophages péritonéaux, état réversible par l’administration orale d’ATRA. De manière intéressante, nous observons également un état d’hyper-activation des monocytes circulants de patients avec MAF, dont la déficience en vitamine A a été démontrée. Ces données suggèrent que la carence en vitamine A présente chez les patients atteints de MAF pourrait faire partie des mécanismes favorisant cet état d’hyper-réponse inflammatoire.Certaines données montrent que la consommation chronique d’alcool induit une stabilisation de l’ARNm de TNF-α, expliquant en partie l’augmentation de ses taux plasmatiques chez les patients avec MAF. D’autres montrent qu’un traitement par l’ATRA est capable de déstabiliser l’ARNm de TNF-α, accélérant ainsi sa dégradation. Nos résultats montrent que la carence en vitamine A chez la souris s’accompagne d’un allongement du temps de demi-vie de l’ARNm de TNF-α exprimé par les macrophages péritonéaux murins, illustrant sa plus grande stabilité comparée aux souris non carencées en vitamine A. La déficience en vitamine A présente dans les MAF pourrait donc expliquer, du moins en partie, l’augmentation des taux de TNF-α par la stabilisation de son ARNm.Finalement, nous avons étudié l’effet de la 1,25(OH)2D sur le phénotype de cellules stellées humaines, impliquées dans le processus de fibrose hépatique. Le traitement de ces cellules par le métabolite actif de la vitamine D diminue leur activation, modifie l’expression de gènes pro- et anti-fibrosants, mais n’a pas d’action sur l’apoptose.En conclusion, nous montrons pour la première fois l’association entre les déficiences en vitamine A/ATRA et vitamine D, et la sévérité des MAF. De plus, nos résultats suggèrent que les carences vitaminiques, présentes chez les patients avec une MAF, pourraient participer à la pathophysiologie de ces maladies en activant les cellules immunitaires, et que leur supplémentation pourrait diminuer l’état pro-inflammatoire et pro-fibrosant délétère de la cirrhose. Les déficiences en vitamines A et D ne seraient pas seulement le reflet de la sévérité de la MAF, mais joueraient bien un rôle dans le développement et la progression des lésions hépatiques. Leur évaluation et leur correction devraient être étudiées comme cible thérapeutique dans la prise en charge des MAF. / Doctorat en Sciences médicales (Médecine) / info:eu-repo/semantics/nonPublished

The association between non-alcoholic fatty liver disease (NAFLD) and atrial fibrillation (AF) has been suggested by recent epidemiological studies although the results were inconsistent. This meta-analysis was conducted to summarize all available data. Methods A comprehensive literature review was conducted using MEDLINE and EMBASE database through May 2017 to identify all studies that reported the risk of AF among patients with NAFLD versus those without NAFLD. Effect estimates from each study were extracted and combined together using the random-effect, generic inverse variance method of DerSimonian and Laird. Results Of 1009 studies, 5 studies (two cross-sectional studies and three cohort studies) with 238,129 participants met the eligibility criteria and were included in the meta-analysis. The risk of AF in patients with NAFLD was significantly higher than subjects without NAFLD with the pooled risks ratio of 2.06 (95% confidence interval, 1.10–3.85). The statistical heterogeneity was high with an I2 of 78%, which was the major limitation of this meta-analysis. Conclusions A significantly increased risk of AF among patients with NAFLD was demonstrated in this study.

Researchers have argued that in times of need having supportive, caring people available can make all the difference between achieving optimum health and well-being or suffering from mental or physical illness (Cobb, 1976; Sarason & Sarason, 1985; Thoits, 1986). The direct-effect model of support postulates that having the knowledge of available relationship resources (i.e., perceived support) and receiving benefits from those relationships (i.e., received support) both have beneficial effects on health behaviors and well-being (Cohen & Wills, 1985). According to the stress-buffering model, when stressors are encountered, the certainty of having available resources, as well as having tangible support resources, is hypothesized to lessen the negative effects of stressors (Cohen, et al., 2000; Cohen &Wills, 1985, Cutrona, 1986; Thoits, 1986). Most of the research that has examined social support effects on drinking-related outcomes has focused on the association between support and alcohol problems, particularly among high risk populations (those who are alcohol dependent, alcohol abusers, or adolescents). Yet, it could be argued that when examining drinking levels, not all consumption is harmful. Of particular concern is drinking that is motivated to reduce negative or stressful experiences. Individuals who use drinking as a method of avoidant coping, or reducing tension drink significantly more alcohol and be at a greater risk for developing later drinking problems (Cooper, Russell, & George, 1988). Research employing daily process methodology has been able to resolve documented methodological inconsistencies (e.g., Greeley & Oei, 1999) by examining the within-person processes between negative experiences and alcohol consumption (Tennen & Affleck, 1996; Tennen, Affleck, Armeli, & Carney, 2000; Mohr et al., 2008). Similarly, these methodologies have been useful to social support researchers in helping to understand social support as a within-person process rather than just an interpersonal event between two individuals. This research was part of a larger study about the influence of alcohol use on daily emotion regulation among 47 moderate-to-heavy drinking adults in the local metropolitan area. Participants carried a personal data assistant (handheld interviewer) for 30 days, responding to surveys three times each day (late afternoon, evening). Each survey probed supportive and negative interpersonal exchanges and drinking behaviors. Prior to the daily diary portion of the study, participants completed the Interpersonal Support Evaluation List, a measure of perceived social support. For purposes of analyses, I examined the extent to which exchanges occurring in an earlier interview predicted subsequent solitary drinking at home using data from 2 of the three interviews (predicting evening and late evening drinking only). My analyses revealed that daily socially supportive exchanges had a significant direct effect on subsequent drinking at home alone. Interestingly, the daily supportive exchanges did not buffer the negative exchanges-later drinking relationship. However, my findings revealed that negative exchanges also resulted in a reduction in subsequent consumption, which contrasts previous studies that used similar methodologies but with heavier drinkers (e.g., Mohr et al., 2001). Further, perceived support was not related to solitary consumption. The results of this study indicate that in healthy adults, positively appraised received support directly reduces solitary consumption. This is an important finding given that received support is difficult to document. At the same time, my results showed that among these types of drinkers, negative exchanges may have a stronger direct effect than positive exchanges on solitary consumption. In non-clinical samples, such as this the relationship between social support and drinking is not straightforward. Thus, using a sophisticated methodology (i.e., daily process methods), this study was able to examine the relationship of drinking and social support on a daily basis; thus, further bridging the gap between social support and the drinking literature.

No description available.

Darbo tikslas. Išanalizuoti alkoholinių gėrimų reklamos situaciją Lietuvoje, gyventojų požiūrį į jos draudimą. Darbo uždaviniai. 1. Išanalizuoti esamą alkoholinių gėrimų reklamą. 2. Nustatyti moksleivių požiūrį į alkoholinių gėrimų reklamą. 3. Nustatyti gyventojų požiūrį į alkoholinių gėrimų reklamos draudimą. 4. Išanalizuoti esminius reklamos kūrimo principus, įvertinti jų naudojimą reklamuojant alkoholinius gėrimus. 5. Įvertinti esamos alkoholinių gėrimų reklamos atitikimą egzistuojančiai įstatyminei bazei, jos pobūdį. Tyrimo metodika. 2007 m. rugsėjo mėn. alkoholinių gėrimų reklamos monitoringo duomenų analizė. Viešosios nuomonės tyrimas. Alkoholinių gėrimų reklamos analizė, atitikimas įstatyminei bazei. Kokybinis moksleivių nuomonės tyrimas. Rezultatai. Lyginant televiziją, spaudą, radiją bei lauko reklamą, daugiausiai alkoholinių gėrimų reklamų 2007 m. rugsėjo mėnesį buvo televizijoje, čia reklama pasiekia daugiausiai gyventojų. Nors stipriųjų alkoholinių gėrimų reklamos transliacijos laikas televizijoje ribojamas, tačiau jas matė 56 proc. tyrime dalyvavusių moksleivių, o 44 proc. apklaustųjų nurodė stipriųjų alkoholinių gėrimų reklamas matę spaudoje. Beveik pusė apklaustų respondentų pritaria alkoholinių gėrimų reklamos uždraudimui. Nors alkoholis yra ypatinga ir valstybės kontroliuojama prekė, jo reklamai naudojamos beveik visos priemonės, kurios naudojamos ir kitų prekių ar produktų reklamai. Išvados. 1. Dažniausiai alkoholiniai gėrimai reklamuojami televizijoje ir... [toliau žr. visą tekstą] / Aim of the study. To analyze the situation of alcohol advertising in Lithuania and the attitude of Lithuanians towards the ban of alcohol advertising. Objectives. 1. To analyze the advertising of alcoholic beverages. 2. To identify the attitude of school students towards the advertising of alcoholic beverages. 3. To determine the attitude of Lithuanian inhabitants towards the ban of alcohol advertising. 4. To analyze the fundamental principles of how advertising is being created and to estimate its application while advertising alcoholic beverages. 5. To evaluate if the current advertisements of alcoholic beverages conform with the present legal basis and its nature. Methods. Gathered data analysis using monitoring of alcoholic beverage advertisements. Public opinion poll. Advertising analysis of alcoholic beverages and its conformance with legal basis. The quantitative school’s pupil’s survey. Results. After comparing the number of advertisements showed on television, print press, radio and outdoor ads showed in September of 2007, it was identified that most of alcoholic beverage ads were showed on TV, as this kind of advertising reaches the majority of people. Although the broadcast time for advertising strong alcoholic beverages on TV is restricted, these ads were seen by 56 percent of pupils participating in the research and 44 percent admitted seeing strong alcoholic beverage ads in the printing press. Almost half of the polled pupils approve the banning of advertising... [to full text]

Thesis (PhD)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Key research areas in modern enology are related to the production of wine of consistent quality, as well as to the improvement of existing wine quality through the enhancement of the sensory properties of wine. The formation of glycerol during alcoholic fermentation is highly relevant to both these issues. Since the early years of the zo" century, glycerol has been positively associated with the quality of wine and it is thought to impart important mouth-feel sensations such as "viscosity", "smoothness" and "body". In general, it is considered that glycerol concentrations higher than those normally found in wine, can contribute towards the improvement of wine quality. It has also been suggested that increased concentrations of glycerol can enhance the aroma of wine. On the basis of these perceptions, several strategies have been developed to favour the production of glycerol during the fermentation process and over a period of years, a large volume of data has been collected that relates to various aspects regarding glycerol production during alcoholic fermentation. To date, however, several aspects regarding the relationship between glycerol and wine quality remain unclear. The reasons for this situation can mainly be ascribed to the lack of reliable analytical data to serve as a basis for investigating the relationship between glycerol and wine quality, as well as the preponderance of empirical and anecdotal evidence. Despite numerous opinions regarding optimal glycerol concentrations in wine, glycerol is indeed seldom assayed on a routine basis and targets with respect to specific wine grape cultivars and glycerol concentrations have largely remained unspecified. To date, very little information regarding glycerol concentrations in South African wines has been published. The analytical techniques that are most frequently used for the quantification of glycerol in grape juice, fermenting must and wine are not easily automated and this aspect placed severe limitations on the generation of large volumes of analytical data on glycerol concentrations in these matrices. This project was undertaken with the aim to holistically address some of the unresolved issues relating to the relationship between glycerol and wine quality. This also implied the development and optimisation of analytical techniques suitable for the rapid and accurate determination of glycerol in fermentation media, as well as in finished wine. In the first stage of this project a quantitative database was established that contained the analytical data on the glycerol concentrations of a statistically significant number of wines of adjudged quality, as well as additional information for each wine regarding the geographic origin, vintage, routine chemical analyses and the yeast strain(s) used for the production of the wine. The relevance of glycerol in wine for the modern South African winemaker was evaluated through the establishment of a quantitative database that contained the opinions of an expert panel of 15 South African winemakers, enologists and wine chemists on topics relating to glycerol in wine. In the second stage of the project the data captured in the databases were used to investigate aspects regarding the relationship between glycerol and wine quality. From the data captured in the qualitative database, it was clear that the topic regarding glycerol in wine was important to the South African winemakers and it was also evident that there was a need for the development and optimisation of methods suitable for the routine analysis of the glycerol concentrations in grape juice, fermenting must and wine. The opinions of the panel members also highlighted the issue that the mouth-feel property of wine was considered to be an area where the quality of some wines could be further improved. The quantitative database contained the information on the glycerol concentrations of 450 commercial South African table wines of adjudged quality. The premium cultivars Chardonnay, Chenin blanc, Sauvignon blanc, Cabernet Sauvignon, Merlot, Shiraz and Pinotage were used for the purpose of investigating the relationship between glycerol concentration and wine quality. The wines represented a wide variety of wine styles, including dry white, off-dry white, dry red and late harvest wines. The average glycerol concentration was significantly associated with the wine style. In white wines the average glycerol concentration was much lower than in the red wines (6.82 gIL versus 10.49 gIL, respectively). No significant relationship between the final glycerol concentration and the geographic origin, vintage and the yeast strain used for the fermentation was found. Wine quality could not be significantly associated with glycerol concentration in the red wines. In the white wines, the relationship between glycerol concentration and wine quality was significant, but due to the very small differences in the average glycerol concentrations of the wines of different quality ratings, the statistical significance is probably of little practical value. The effect of glycerol on the volatility of a selection of esters and higher alcohols was also investigated. Solid-phase microextraction, followed by gas chromatography, was used to analyse the composition of the headspace at equilibrium between the liquid phase and the gas phase of a model wine, and a dry white wine that contained a basal concentration of 5.4 gIL glycerol. Results showed that incremental increases in the glycerol concentrations over a range of 1 -10 gIL in the model wine and in a Chenin blanc wine, were not accompanied by a proportional increase or decrease in the abundance of the aroma components in the headspace. The volatile components tested were isoamyl acetate, ethyl butyrate, ethyl valerate, ethyl lactate, ethyl hexanoate, hexyl acetate, isoamyl alcohol and isobutanol. For all the volatile components tested, the difference between the headspace composition of samples containing the lowest glycerol concentration, and those containing the highest glycerol concentration, was not significant. However, sufficient experimental evidence was obtained to indicate that increasing glycerol concentrations had an effect on the volatility of aroma components, and that the effect is of a complex and non-linear nature. In the third phase of the work Fourier transform infrared spectroscopy (FT-IR) was used to establish and optimise methods for the accurate and rapid quantification of glycerol in wine. For this purpose calibrations were developed for the quantification of glycerol in dry wine and late harvest wines. The accuracy of prediction was evaluated by means of the standard error of prediction that was 0.38 gIL for the dry wines and 0.65 gIL for the sweet wines. Large variations are introduced in the FT-IR spectra of wine by factors such as process technology, cultivar and geographic origin, and this variation can have an effect on the accuracy of the analytical data generated when employing FT-IR spectroscopy. Using glycerol prediction in wine as a model system, principal component analysis of the FT-IR spectra was done in order to establish quality control measures for the detection of poorly predicted, or outlier samples. A classification model, based on principal component analysis, was established that enabled the interpretation and classification of the outlier samples in the data set in 100% of the cases tested. This work forms the basis for expanding the quality control measures for the detection of wines of which the FT-IR spectra are highly unnatural, as well as for establishing quality control measures to ensure that accurate analytical data are generated when FT-IR is used. FT-IR spectroscopy was also used to develop a rapid screen for the evaluation of the fermentation profiles of wine yeasts. For this purpose, a selection of wine yeasts, which included commercial wine yeasts frequently used in winemaking in South Africa, as well as a selection of hybrid Saccharomyces cerevisiae yeasts, that were obtained through a selective breeding strategy aimed at increasing glycerol concentrations were used. Calibrations necessary for the accurate quantification of glycerol, volatile acidity, ethanol, reducing sugar and glucose, in Chenin blanc must and a synthetic must were developed and optimised. This work forms the basis upon which the scope of the analysis, both in terms of the number of components that can be measured, as well as the medium in which the yeasts are being evaluated, can be enlarged. This would be valuable for future applications in both the research as well as the industrial environment. The method that was developed serves to illustrate how this application can play a supportive role in yeast development programmes, through the speeding up of the initial stages of yeast strain evaluation. / AFRIKAANSE OPSOMMING: Navorsing in moderne wynkunde is sterk gefokus op die produksie van wyn waarvan die kwaliteit van In volhoubare goeie peil is, sowel as die verdere verbetering van bestaande wynkwaliteit, deur In verhoging van die sensoriese eienskappe van wyn. Die vorming van gliserol tydens alkoholiese fermentasie het betrekking op beide hierdie aspekte. In Opvatting wat wyd gehuldig word en wat reeds sedert die vroeë jare van die 20e eeu geld, impliseer dat gliserol In positiewe bydrae lewer tot wynkwaliteit. Oor die algemeen word dit beskou dat gliserolvlakke hoër as wat normaalweg in wyn aangetref word, kan bydra om die kwaliteit van die wyn nog verder te vehoog. Daar is ook spekulasie dat verhoogde gliserolvlakke in wyn die intensiteit van die aroma van wyn kan verhoog. Hierdie opvattings het tot gevolg gehad dat veskeie strategieë ontwikkel is om die gliserol vlakke wat tydens die fermentasieproses gevorm word, te verhoog. Baie min inligting oor die gliserolinhoud van Suid-Afrikaanse wyn is tot onlangs gepubliseer. Ten spyte van die opvattings oor gliserol en wynkwaliteit wat reeds oor In lang tydperk gehuldig word, bly sekere aspekte van die verwantskap tussen gliserol en wynkwaliteit nog steeds onduidelik. Redes vir hierdie situasie kan hoofsaaklik toegeskryf word aan die totale afwesigheid van betroubare en substansiële eksperimentele data wat as basis kan dien vir die evaluering van die algemene opvattings aangaande die verwantskap tussen gliserol en wynkwaliteit. Die inligting wat wel beskikbaar is, is verder ook oorwegend van In empiriese aard. Huidig word gliserol selde op In roetine basis in die analitiese laboratorium bepaal, hoofsaaklik omdat die bestaande metodes tydrowend is en nie maklik geoutomatiseer kan word nie. In hierdie studie is In kwantitatiewe databasis opgestel waarin die inligting ten opsigte van die gliserolvlakke van 450 kommersiële Suid-Afrikaanse tafelwyne waarvan die kwaliteit beoordeel is, vervat is. Die kultivars Chardonnay, Chenin blanc, Sauvignon blanc, Cabernet Sauvignon, Merlot, Shiraz en Pinotage is gebruik vir hierdie doel en die seleksie van wyne was verteenwoordigend van In wye verskeidenheid wynstyle, insluitende droë wit-, halfdroë wit-, droë rooi- en laatoeswyne. Die gemiddelde gliserolvlakke in die witwyne was heelwat laer as die gemidelde gliserolvlakke in die droë rooiwyne (6.82 gIL teenoor 10.49 gIL, onderskeidelik). Geen beduidende verwantskap kon aangetoon word tussen die gliserolkonsentrasie in die wyn en die geografiese oorsprong, oesjaar, en die gisras wat gebruik is in die produksie van die wyn nie. Die kwaliteit van rooiwyn kon nie beduidend met die gliserolkonsentrasie geassosieer word nie. In die geval van wit wyn was die verwantskap statisties beduidend, maar die verskille was klein en moontlik nie van veel praktiese waarde nie. Die aktualiteit van gliserol vir die moderne Suid-Afrikaanse wynmaker is geëvalueer op grond van die opinies van In paneel van 15 Suid-Afrikaanse kundiges, rakende aspekte wat verband hou met die algemene opvattings oor gliserol en wyn. Die paneel het bestaan uit wynmakers, wynkundiges en chemici. Die opinie van die panel is deur middel van "n vraelys bekom en is vervat in "n kwalitatiewe databasis. Die resultate van hierdie menigspeiling het getoon dat gliserol wel vir die Suid- Afrikaanse wynmakers belangrik is en dit het ook die behoefte uitgewys vir die ontwikkeling en optimisering van metodes wat geskik is vir die roetine analyses van gliserol in wyn. Die invloed van gliserol op die vlugtigheid van "n seleksie van hoëralkohole en esters is ondersoek in "n model wyn sowel as "n wit wyn, waarvan die basiese gliserolkonsentrasie 5.4 gIL was. Soliede-fase mikroekstraksie van die gasfase van wyn is opgevolg met "n gaschromatografiese analise. Resultate het getoon dat "n stapsgewyse toename in die gliserol konsentrasie, oor "n konsentrasie reeks van 0 - 10 gIL in die model wyn, en 0 - 15 gIL in die wit wyn, nie gepaard gegaan het met "n reglynige toename of afname in die konsentrasie van die aromakomponente nie. Vir al die komponente wat ondersoek is, was die samestelling van die gasfase in monsters wat die laagste gliserol konsentrasie gehad het, teenoor dié wat die hoogste gliserol konsentrasie gehad het, nie beduidend nie. Nietemin het die resultate getoon dat gliserol wel "n effek het op die vlugtigheid van die aroma komponente wat in hierdie ondersoek gebruik is, maar dat die aard van die effek kompleks en nie-liniê is. Fourier-transformasie-infrarooispektroskopie (FT-IR) is gebruik om die metodes vir die analise van gliserol in wyn sodanig te optimiser, dat vinnige en akkurate bepalings op "n roetine basis in wyn gedoen kan word. Kalibrasies is ontwikkel vir die kwantifisering van gliserol in droëwyn en laatoeswyn. Die standaard voorspellingsfout van die kalibrasies wat ontwikkel is, was 0.38 gIL in droëwyn en 0.65 gIL in die geval van laatoeswyn. Inherente variasie in die FT-IR-spektra word deur eksterne faktore soos die proses tegnologie wat gebruik is om die wyn te berei, die kultivar en geografiese oorsprong van die wyn veroorsaak en hierdie variasie kan "n effek hê op die voorspelingsakkuraatheid van FT-IR spektroskopie. Om die effek van hierdie variasie op die akkuraarheid van die analitiese data te evalueer, is die voorspelling van gliserol as modelsisteem gebruik. Hoofkomponentanalise van die FT-IR spektra is gedoen om dié wyne met onnatuurlike FT-IR-spektra te identifiseer, ten einde beheer oor die akkuraatheid van die analitiese data uit te oefen. "n Verdere model wat ook gebaseer is op hoofkomponentanalise van die FT-IR-wynspektra is ontwikkel vir die interpretasie en klassifikasie van wynmonsters met onnatuurlike FT-IRspektra. Met die model wat ontwikkel is kon onnatuurlike wynmonsters met "n akkuraatheid van 100% gëidentifiseer word. Hierdie werk vorm die basis waarop kwaliteitsbeheer verder uitgebrei kan word sodat wyne met onnatuurlike spektra gëidentifiseer kan word, sowel as om te verseker dat akkurate data gegenereer word as FT-IR as analitiese metode gebruik word vir die kwantifisering van gliserol in wyn. FT-IR spektroskopie is ook gebruik om "n vinnige skandeerproses te ontwikkel waarmee die fermentasieprofiele van wyngiste geëvalueer kan word. Die seleksie giste wat vir hierdie doel gebruik is, sluit kommersiële Suid-Afrikaanse wyngiste in, sowel as hibriede Saccharomyces cerevisia-giste wat normaalweg hoër vlakke van gliserol tydens die fermentasieproses produseer. Kalibrasies is ontwikkel vir die akkurate kwantifisering van gliserol, vlugtige suur, alkohol, reduserende suiker en glukose, in Chenin blanc-mos sowel as in 'n sintetiese medium. Hierdie werk vorm die basis waarop verdere uitbreidings gedoen kan word, sodat meer metaboliete gemeet kan word en 'n groter verskeidenheid van fermentasiemedia gebruik kan word. Hierdie ontwikkeling is waardevol vir toekomstige toepassings in die navorsings- sowel as die industriële omgewing. Die metode wat ontwikkel is illustreer ook hoe hierdie toepassing 'n ondersteunende rol kan speel in wyngisontwikkelingsprogramme deur die aanvanklike evalueringsproses van die giste te versnel.