Includes bibliographical references (34 leaves). / xxi, 204 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates the in vitro antioxidant properties of red wine containing polphends and the isoflavone genistein. Subsequently the effect of red wine on low density lipoprotein oxidation and fatty streak lesion development in cholesterol-fed rabbits was examined. / Thesis (Ph.D.)--University of Adelaide, Dept. of Clinical and Experimental Pharmacology, 1998

[Formulae and special characters can only be approximated here. Please see the pdf version of the abstract for an accurate reproduction.] Two randomised controlled trials were conducted to explore the relationship between the consumption of alcoholic beverages and cardiovascular disease risk factors. Study 1 was primarily designed to test the hypothesis that the cardio-protective effect of light alcohol could be mediated, in part, via improvements in endothelial function. Study 1 was also designed to explore the effect of alcohol on both traditional risk factors for cardiovascular disease, such as changes in lipid profile, haemostatic factors and blood pressure, and novel risk factors such as homocysteine, markers of inflammation and oxidative stress. The experimental design of this study also allowed us to determine whether reducing alcohol intake in these moderate-to-heavy drinkers could improvement insulin sensitivity, a component of the metabolic syndrome. In this group of sixteen healthy middle-aged men with a history of moderate to heavy alcohol intake of seven standard drinks per day, reducing intake down to approximately one standard drink per day for four weeks had no beneficial effects on conduit vessel endothelial function as assessed by post-ischaemic brachial artery flow-mediated dilatation, nor were there any detectable changes in soluble E-selectin, endothelin-1 and von Willebrand Factor, which are considered biomarkers of endothelial activation. As this study did not investigate the effect of alcohol on endothelial function in resistance vessels, it cannot exclude the possibility that alcohol may affect endothelial cells resident in that vascular bed. This study does show and confirm, however, that the relationship between alcohol and risk factors for cardiovascular disease is an extremely complex one. On the one hand it demonstrated that alcohol was potentially harmful, increasing blood pressure, plasma F2-isoprostane (oxidative stress), and homocysteine. On the other hand it showed that increasing alcohol intake led to significant reductions in two (i.e. fibrinogen and IL-6) of five inflammatory markers, in addition to improving the HDL-cholesterol profile of these subjects. Although the effects of alcohol on blood pressure, fibrinogen and HDL-cholesterol are not in themselves new, they support our choice of study design and strengthen the argument in favour of accepting the more novel findings of this study, specifically, the lack of effect on endothelial function and insulin sensitivity, and the harmful effect of alcohol in increasing oxidative stress and homocysteine. Study 2 was primarily designed to test the hypothesis that the consumption of red wine may confer greater cardio-protection than beer via improvements in endothelial function. Simultaneously, the study was also designed to determine whether drinking red wine for 4-weeks would have different effects than beer on either traditional risk factors for cardiovascular disease (i.e. blood pressure and lipid profile) or the more novel risk factors, homocysteine and oxidative stress. Using a randomised controlled cross-over study design, Study 2 provides evidence that the regular daily consumption of 4 standard drinks of either beer or red wine does not alter endothelial function, as measured by post-ischaemic flow-mediated vasodilatation of the brachial artery in healthy middle-aged men, nor was there evidence of any beneficial effect of de-alcoholised red wine on brachial artery response. As compliance with drinking protocol was confirmed with increased serum γ-GT and HDL during red wine and beer periods, and increased 24-hr urinary excretion of 4OMGA during red wine and de-alcoholised red wine periods, we are confident that there was excellent compliance with the beverage treatments. Study 2 also provides the first evidence from a carefully controlled intervention study that both red wine and beer elevate blood pressure to a similar degree, with no detectable difference in the magnitude of either treatment. As with endothelial function, there was also no evidence of any beneficial effect of de-alcoholised red wine on blood pressure. In addition, although post hoc analysis found evidence that alcohol increased both plasma homocysteine and urinary excretion of F2-isoprostane and endothelin-1, there was no apparent protective effect conferred from either red wine or de-alcoholised red wine on these cardiovascular risk markers. The results from this study cannot disprove the hypothesis that red wine is more beneficial for cardiovascular health; however, they suggest that if red wine has properties beyond those of beer to confer protection, they are not via any interactions with the nitric oxide regulatory function of the endothelium in conduit vessels nor are they via moderation of the vasopressor, homocysteine-raising, and oxidative stress effects of alcohol. The interpretation of the findings from both intervention studies and their place in the context of our current understanding of the role that alcoholic beverages play in the development and/or prevention of cardiovascular disease are explored in this thesis.

Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2007. / Biogenic amines are nitrogenous compounds of low molecular weight found in most fermented foods, including wine. These biologically produced amines are essential at low concentrations for normal metabolic and physiological functions in animals, plants and micro-organisms. However, biogenic amines can have adverse effects at high concentrations and pose a health risk for sensitive individuals. Symptoms include nausea, hot flushes, headaches, red rashes, respiratory distress and fluctuations in blood pressure. A number of countries have implemented upper limits for histamine in food and wine. This development has already started to threaten commercial export transactions and may become more serious in the near future, especially in the competitive wine industry of today. The most important biogenic amines in wine include histamine, tyramine, putrescine, cadaverine and phenylethylamine which are produced from the amino acids histidine, tyrosine, ornithine, lysine and phenylalanine respectively. Biogenic amines are mainly produced in wine by microbial decarboxylation of the corresponding precursor amino acid. It may be produced by yeast during alcoholic fermentation, by lactic acid bacteria during malolactic fermentation, or potentially by spoilage microbes such as acetic acid bacteria and Brettanomyces. However, lactic acid bacteria are widely accepted as the main causative agents. Inoculation with commercial malolactic fermentation starter cultures that do not possess the relevant decarboxylase genes may inhibit the growth and activity of decarboxylase positive indigenous bacteria and as such control the production of biogenic amines in wine. In this study it was shown that co-inoculation of malolactic starter cultures together with alcoholic fermentation could reduce the incidence of biogenic amines in wine compared to conventional inoculation protocols; presumably because undesirable activities were restrained at an earlier stage during co-inoculation. It was also indicated in this work that in some cases the effect of co-inoculation on biogenic amine reduction may only be visible after a period of ageing. The frequency of biogenic amine occurrence in wines aged for a short period was generally higher in the presence of fermentation lees than in its absence. This work also included a preliminary investigation into the contribution of commercial wine yeast starter cultures to biogenic amine production. Diamines and polyamines (putrescine, spermidine and cadaverine) were produced to variable extents by all yeasts with very little or no production of physiologically important biogenic amines (histamine, tyramine and phenylethylamine). Another objective of this study was to evaluate the influence of common winemaking practices on biogenic amine production under winemaking conditions. We have shown that biogenic amine production by lactic acid bacteria could be influenced, amongst others, by the presence of precursor amino acids in the grape must or wine, the time of contact between juice or wine and grape skins, the time of contact between wine and yeast lees, the presence of microbial nutrients, wine pH, sulphite and ethanol levels, the phenolic composition of the wine and the number of decarboxylase positive lactic acid bacteria present in the wine. Lately, the wine industry is under increasing pressure to increase measures to ensure food safety and security and to eliminate any compound, present even in trace amounts that could reduce the wholesomeness of the wine. The need arises for a rapid and inexpensive method for quality control. In this study we investigated the potential to use Fourier transform infrared spectroscopy to rapidly screen for the presence of elevated levels of biogenic amines. This presents a novel method for the detection and quantification of total biogenic amines in wines.