Thesis (Ph. D.)--University of Wisconsin--Madison, 1934. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Phytosterols occur naturally in the non-saponifiable material of plant oils. Sitostanol, the saturated derivative of beta-sitosterol, is found in negligible concentrations in plant sources and, hence, is almost absent from typical Western diets. Tall oil extracts, on the other hand, contain about 20% (w/w) sitostanol. Phytosterols have been shown to lower plasma total cholesterol levels in animals and humans while sitostanol exhibited stronger reducing effects. Several studies have suggested that phytosterols lower plasma total cholesterol levels by either inhibiting cholesterol absorption or altering the activities of enzymes critical in cholesterol metabolism and excretion. However, results obtained demonstrate inconsistency regarding the effects of phytosterols on cholesterol absorption rates and cholesterogenesis. In addition, few studies have determined quantitatively the changes in the rate of cholesterol absorption and biosynthesis. Hence, the objective of this thesis was to investigate further the impact of different sources of phytosterols on plasma lipid profiles and to develop a new methodology for simultaneous measurement of percent cholesterol absorption and cholesterol synthesis rates in animals and humans. The stable isotopes, 13C-, 18 O-cholesterol, and deuterium oxide were utilized for the dual isotope plasma ratio and deuterium uptake methodologies. Results from the series of animal experiments conducted demonstrate (i) a gender effect of phytosterols in modulating plasma lipid profile in hamsters, (ii) that sitostanol was more potent in lowering plasma and hepatic lipid concentrations than beta-sitosterol in hamsters and rabbits and (iii) that this lowering effect was due to a reduction in fractional cholesterol absorption and an increase in cholesterol excretion rates. Concomitantly, an up-regulation in cholesterogenesis was observed in hamsters. Furthermore, in humans tall oil phytosterols lowered total cholesterol levels in hypercholesterole

Atherosclerosis is the primary underlying pathology of CVD. Dietary treatment may be considered as one of the initial steps in the prevention of atherosclerosis. Replacing refined carbohydrate source of a cholesterol- enriched diet with antioxidant rich whole grain and inclusion of phytonutrition in the diet such as wild rice and phytosterols may reduce cardiovascular risk factors. The wild rice (Zizania palustris L.), an annual plant native to aquatic areas of the northern America, receives much attention by researchers because of its potent nutritional and phytochemical contents. Furthermore, another dietary component with cardiovascular benefits is the inclusion of plant sterols in our daily diet. The aim of this study was to investigate the antiatherogenic activity of wild rice in combination with phytosterols in LDL-r-KO mice. Male LDL-r-KO mice were divided into 4 groups receiving one of the following experimental diets for 20 weeks: 1. Atherogenic diet, 2.Wild rice (as the main source of dietary carbohydrates) diet, 3. 2% Phytosterols-enriched diet and 4. Diet containing both wild rice and 2 % phytosterols. Blood samples were collected through jugular vein during study, and at sacrifice through cardiac puncture; the heart and fecal materials were collected and used for biochemical and histological examinations. The supplementation of wild rice in combination with phytosterols to an atherogenic diet for up to 20 weeks significantly reduced the total plasma concentrations of cholesterol (TC) in LDLr-KO mice. However, there was no significant difference in triglyceride (TG) in wild rice in combination with phytosterols after 20 week exposure of diet. Further, wild rice in combination with phytosterols resulted in increased fecal excretion of cholesterol. Also, there was reduction in the development of atherosclerotic lesion in the group of mice supplemented with wild rice in combination with 2% phytosterols (w/w). Our data support that combination of plant sterols and wild rice does not have additive effect in lowering cardiovascular risk.

Phytosterols play an important role in nature and as synthetic supplements for the modification of cholesterol metabolism in humans. The consensus is that the primary mechanism by which phytosterols modify lipid profiles is through altering the absorption of cholesterol. This thesis examined the effects of phytosterol mixtures on (i) de novo cholesterol synthesis rates and appearance of de novo cholesterol into the cholesterol ester pool through the use of deuterium incorporation, as well as, (ii) plasma lipid and sterol concentrations in normolipidemic humans. The initial investigation of this thesis compared the effects of diets based on either corn oil, olive oil, or olive oil plus phytosterol mixture on cholesterol metabolism. Each treatment was administered for 10 days in a cross-over design to 16 normolipidemic humans. In addition to confirming prior conclusions that corn oil was more effective than olive oil at decreasing plasma total and LDL-cholesterol concentration, this study was one of the first to determine that the differential effects on cholesterol metabolism observed in humans consuming corn versus olive oil is due, in part, to the higher concentrations of plant sterols naturally found in corn oil. The second study presented in this thesis investigated the differential effects on sterol metabolism of phytosterol mixtures either enriched with sitostanol or sitostanol-free administered for 10 days in 11 normolipidemic humans. The results of this study demonstrated that only the phytosterol mixture containing low doses of sitostanol decreased plasma total and LDL-cholesterol concentrations and increased the circulating HDL/LDL ratios; thus, the sitostanol-enriched phytosterol mixture was a more effective cholesterol-lowering agent.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1939. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references: leaves 51-53.

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Introdução-- Os fitosteróis (FS) são esteróis de origem vegetal, reconhecidos como componentes funcionais devido ao seu papel hipocolesterolêmico. A recomendação de ingestão diária desses compostos é de 1,6 a 2 g/dia, no entanto há poucos estudos que avaliem os teores desses compostos em alimentos, sendo necessária sua quantificação. Objetivo - O objetivo deste projeto foi desenvolver uma metodologia e determinar os teores de FS em alguns alimentos usualmente consumidos e comercializados em São Paulo. Metodologia Foram avaliadas amostras de creme vegetal sem sal (in natura, e aquecidas a 100o C e 140o C), dos farináceos: farinha de trigo, farinha de milho, farinha de mandioca, amido de milho, café em pó (torras: tradicional, forte e extraforte, descafeinado e gourmet), café solúvel instantâneo, cappuccino e da bebida coada. As amostras, em triplicata, foram submetidas ao processo de saponificação a frio e a matéria insaponificável extraída foi derivatizada e posteriormente injetada em cromatógrafo gasoso. Resultados Os principais FS encontrados foram: -Sitosterol, campesterol e estigmasterol. As maiores médias de teores de FS foram encontradas nos cremes vegetais (186,2 ± 21,7 mg /100g) e nos pós de café moído (92,24 ± 3,95 mg /100g). As farinhas apresentaram teores intermediários, 42,27 ± 7,09 mg /100g; 35,10 ± 10,49 mg /100g; 22,02 ± 1,22 mg /100g; 14,33 ± 3,07 mg /100g para farinha de rosca, milho, trigo e mandioca, respectivamente. As amostras cappuccino (5,73 ± 0,78 mg /100g), café solúvel (4,03 ± 0,84 mg /100g) e amido de milho (3,55 ± 0,8 mg /100g) foram as apresentaram menores teores de FS. Nas amostras de creme vegetal, o processamento térmico reduziu os teores totais de FS das amostras in natura em 10 por cento e 53,7 por cento , para os aquecimentos até 100o C e 140o C, respectivamente. . Não houve influencia do grau de torra e do processo de descafeinização nos teores totais de FS encontrados nas amostras de pó de café moído. Conclusão: De acordo com os resultados obtidos os alimentos com maior teor de fitosteróis são a creme vegetal e o pó de café. Pode-se considerar que o creme vegetal, mesmo sem adição de FS é boa fonte desse nutriente. Nas amostras de café o processamento térmico pouco influenciou nos teores de FS, o mesmo não aconteceu com as amostras de creme vegetal. As mais baixas concentrações de FS foram observadas nas amostras de farinhas, amidos, cappuccino e café em pó solúvel. / Introduction: Phytosterols (PS) are plant sterols, known as functional components due to its hypocholesterolemic role. The recommendation for daily intake of these compounds is 1.6-2 g/day, however there are few studies that evaluate the content of these compounds in foods, requiring its quantification. Objective: the objective of this project was to develop a methodology and determine the content of PS in some foods usually consumed and traded in Sao Paulo. Methodology: Were evaluated samples of: unsalted vegetable cream (in natura, and heated to 100oC and 140oC), farinaceous: wheat, corn and cassava flour, breadcrumbs and cornstarch, powdered coffee (roasts: traditional, strong and extra strong, decaffeinated and gourmet), instant coffee, cappuccino and strained drink coffee. Samples in triplicate were subjected to cold saponification process and unsaponificable matter was extracted, derivatized and subsequently injected into the gas chromatograph. Results: The main PS founded in the samples were: -sitosterol, campesterol and stigmasterol. The highest average levels of PS were found in vegetable creams (186.2 ± 21.7 mg / 100g) and powdered coffee (92.24 ± 3.95 mg / 100g). Farinaceous had intermediate levels, 42.27 ± 7.09 mg / 100g; 35.10 ± 10.49 mg / 100g; 22.02 ± 1.22 mg / 100g; 14.33 ± 3.07 mg / 100g for breadcrumbs, corn, and wheat and cassava flour, respectively. Cappuccino samples (5.73 ± 0.78 mg / 100g), soluble coffee (4.03 ± 0.84 mg / 100g) and corn starch (3.55 ± 0.8 mg / 100g) showed lower levels of PS. In samples of vegetable cream, thermal processing reduced in 10 per cent and 53.7 per cent , for heating up to 100°C and 140°C, the total content of PS comparing with in natura samples. There was no influence of the degree of roasting and decaffeination process in the total levels of PS founded in samples of ground coffee powder. Conclusions: According to the results, in the samples evaluated, foods with the highest content of phytosterols are vegetable cream and powder coffee. Margarine can be considered good source of PS even without it industry addition. The heat treatment did not affected the PS content in the coffee samples, however, the same didn\'t happen with samples of vegetable cream. The lowest concentrations of PS were observed in samples of farinaceous, cappuccino and soluble coffee.

The objective of this research was to examine the effects of sitosterol and sitostanol supplementation on plasma cholesterol levels and cholesterol metabolism in hypercholesterolemic subjects consuming a fixed foods diet in a four-phase crossover design. It was hypothesized that addition of either phytosterols, phytostenols, or a 50:50 mixture of sterols and stanols to butter would reduce circulating cholesterol levels, despite butter's hypercholesterolemic effect, through actions involving cholesterol absorption, synthesis, and turnover rates. The data obtained indicate that in their free, unesterified form, plant sterols and stanols lower plasma LDL cholesterol equivalently in hypercholesterolemic subjects. Results of this study provide new data that phytosterols and stanols function by suppressing cholesterol absorption while increasing cholesterol synthesis, however, the de-suppression in synthesis cannot fully compensate for the decrease in absorption making the treatment effective, thus may assist in the development of a food which offers health-promoting advantages related to the prevention of cardiovascular disease.

The minimal refining method described in this study made it possible to neutralize crude canola oil using some weaker alkali such as Ca(OH)2, MgO and Na2siO3 as an alternative for NaOH. After citric acid degumming, more than 98% of phosphorous content was removed from crude oil. The free fatty acid content after minimal neutralization with calcium hydroxide decreased from 0.50 to 0.03%. Other quality parameters such as peroxide value, anisidine value and chlorophyll content were within commercially acceptable levels. The use of Trisyl silica and Magnesol R60 made it possible to remove the hot water washing step and to decrease the amount of remaining soap to less than 10 ppm. There was no significant change in chemical characteristics of canola oil after wet and dry bleaching. During traditional neutralization, total tocopherol loss was 19.6% while minimal refining with Ca(OH)2, MgO and Na2siO3 resulted in 7.0, 2.6 and 0.9 % reduction in total tocopherols. Traditional refining removed 23.6% of total free sterols, although after minimal refining free sterols content did not change significantly (p<0.05). Both traditional and minimal refining resulted in almost complete removal of polyphenols from canola oil. Total phytosterols and tocopherols in two cold press canola oils were 7700, 8400 mg/kg and 370, 350 mg/kg, respectively. Total phytosterols and tocopherols contents in solvent extracted canola oil were 9500, 500 mg/kg, respectively. The minimal refining method described in this study was a new practical approach to remove undesirable components from crude canola oil confirmed with commercial refining standards as well as preserving more healthy minor components. / This research project is supported by National Services and Engineering Research Council of Canada (NSERC).