Browsing by Subject "Dietary fiber"

Now showing 1 - 4 of 4
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    Effect of extraction conditions and oxidative cross-linking on the chemical structure and microbial fermentability of arabinoxylans
    (2013-06) McClatchey, Bridget Colleen
    The aim of this thesis project was to obtain corn bran AX of varying structure by using different extraction conditions, oxidatively cross-link them, and determine the microbial fermentability of both the non-cross-linked and cross-linked samples. To reach this goal the following objectives were defined: *Determine the influence of NaOH concentration used for AX extraction on structural characteristics of extracted AX. *Determine the influence of a post extraction procedure, ball milling, on the structural characteristics of extracted AX. *Cross-link differently extracted AX by using laccase and oxygen. *Determine the effects of ferulate cross-linking on fermentability in an in vitro fermentation experiment and analyze fermentation end products (pH, gas volume, and SCFAs). *Determine the release/formation of phenolic metabolites by gut microorganisms as well as the percentage of original FA being metabolized by gut microbiota.
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    The effect of viscous and fermentable dietary fiber consumption on adiposity, insulin resistance and fuel utilization in rats
    (2013-05) Brockman, David Andrew
    The incidence of obesity continues to be a major public health problem in the United States and comorbidities such as type 2 diabetes, cardiovascular disease and fatty liver that accompany obesity have dramatically increased over the last several decades. The health costs associated with the diagnosis and treatment of obesity-related disorders, particularly type 2 diabetes, are extraordinary and will be an enormous financial burden on the economy. Due to these dire circumstances, there is great interest in identifying foods that reduce the accumulation of adipose tissue and decrease the progression of insulin resistance. The consumption of dietary fibers that decrease the postprandial glucose curve is associated with decreased adiposity and a reduced incidence of type 2 diabetes, but it is controversial as to which property of dietary fiber is responsible for these effects. The objective of this research was to investigate the effect of increasing the small intestinal contents viscosity on the progression of obesity and type 2 diabetes. In the first study, non-fermentable hydroxypropyl methylcellulose (HPMC) was used to increase the small intestinal contents viscosity in a model of obesity with type 2 diabetes, the Zucker Diabetic Fatty rat. Rats fed HPMC showed improvements in insulin resistance and fatty liver but only a modest effect on reducing obesity. There was also a decrease in diabetic wasting as there was a greater food efficiency ratio and less urinary glucose excretion. In the second study, it was shown that adding barley flour containing a high concentration of viscous fermentable β-glucans had similar outcomes to those observed in the first study, including decreased insulin resistance and fatty liver, and a greater concentration of plasma adiponectin. In the third study, a model of diet-induced obesity was used to determine differences in fuel utilization when consuming viscous dietary fibers. Adding non-fermentable HPMC and fermentable guar gum to a high fat diet significantly decreased adiposity and fatty liver, yet there was no difference in insulin resistance. Consumption of both HPMC and guar gum increased the postprandial respiratory quotient compared to cellulose and also increased metabolic flexibility. There was no added effect of fermentability on any measure of adiposity, glucose control or fatty liver disease, indicating that SCFAs produced from fermentation had little or no effect on metabolic disease. In summary, the consumption of soluble dietary fibers that increase the viscosity of the small intestinal contents reduces the progression of obesity, insulin resistance and fatty liver, while the property of fermentation appears to have little discernable effect.
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    Effects of dietary fiber on swine intestinal epithelial and immune response
    (2017-05) Ferrandis Vila, Marta
    In order to reduce feed costs, the use of high-fiber ingredients such as corn dried distiller’s grains with solubles and wheat middlings has become a common practice among swine farmers. However, caloric efficiency and growth of pigs fed high-fiber feed ingredients is usually less than pigs fed corn-soybean meal diets. Supplementation of pigs fed high-fiber diets with fiber-degrading enzymes is an approach to increase energy and amino acid digestibility that may result in a more cost-effective production method. Different components of fiber will modify the intestinal microbiome and epithelial parameters such as mucin expression, likely leading to changes in the intestinal immune response. Therefore, the focus of this thesis is to identify the cytokine profile in the swine intestine caused by fiber sources and fiber-degrading enzymes, and to define whether fiber actions on the intestinal epithelium are mediated through the activation of a localized immune response.
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    Investigation of Purification of Oligosaccharides Produced Using Twin-Screw Extrusion
    (2021-01) Monsefi Parapari, Ghazal
    Lactose, a low value dairy product, was polymerized to a soluble dietary fiber called polylactose using twin-screw extrusion. Non- enzymatic browning reactions occurring during extrusion produce colored compounds and hydroxymethylfurfural. Thisresearch focuses on development and optimization of a purification method for polylactose using activated carbon and resins. Polylactose was ground, solubilized in water at three different concentrations (50 mg/mL, 100 mg/mL and 150 mg/mL). Forty mL of polylactose solution was flowed through the filtration system utilizing gravity. The filtration system was rinsed with 20 mL double distilled water. The rinse water plus the filtrate collected were freeze dried to achieve a powder form suitable for different analysis. 42.4% Purolite A874 resin followed by 42.4% Activated carbon and 3% diatomaceous earth was proven to have the best purification results increasing dietary fiber content from 54.48% to 92.24% while reducing the hydroxymethylfurfural content by 90.91% to a level that was lower than the maximum level determined by the Joint FAO/WHO Expert Committee on Food Additives HMF limit in polydextrose (0.1%). Furthermore, the effect of polylactose solution concentration for filtering 40 mL polylactose solution was determined. Using 50 mg/mL concentration achieved the highest dietary fiber content. This could be since less polylactose had to interact with the same amount of filtration material resulting in removing more impurities and caramelization products. However, the hydroxymethylfurfural content reduction was the same for 50 mg/mL and 100 mg/mL concentrations.