Browsing by Subject "Antioxidant"

Now showing 1 - 4 of 4
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    Effect of cereal grains on the formation of heterocyclic aromatic amines in fried beef patties
    (2012-08) Kyllo, Rachel Renae
    The effect of incorporating flours representing different anatomical parts of the grain of corn, wild rice, and oat as well as corn bran extract into beef patties on the formation of heterocyclic aromatic amines (HAAs) during grilling was investigated. Beef burgers containing 5 or 10% dry cereal solids or cereal extract adsorbed to a cellulose carrier were grilled for 7 minutes per side on an electric grill. The HAA content of the cooked material was assessed using an optimized solid-phase extraction method, reversed-phase HPLC separation, and UV and fluorescence detection. 9H-Pyrido[3,4-b]indole (norharman), 1-methyl-9H-pyrido[3,4-b]indole (harman), 9H-pyrido[2,3-b]indol-2-amine (A-alpha-C), 1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridin-2-amine (PhIP), and 3,8-dimethyl-3H-imidazo[4,5-f]quinoxalin-2-amine (MeIQx) were detected in all burgers. Norharman and harman formation were significantly increased in fried beef patties grilled with wild rice hulls, wild rice flour, and oat hulls. Other treatments also tended to increase beta-carboline (harman and norharman) and PhIP levels relative to plain beef patties. Due to the analytical set-up it was not possible to obtain a full set of reliable data about the effect of cereal materials on the formation of MeIQx, but some materials may be able to reduce the formation of this HAA. It is concluded that the addition of whole cereal materials in beef patties is not an effective way to reduce the formation of beta-carbolines and PhIP during grilling. Definite conclusions about the effect of cereal materials on the formation of MeIQx and structurally related HAAs cannot be drawn from this study.
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    Effects of dietary Peroxidized lipids on the growth performance and metabolic oxidative status of nursery pigs
    (2014-06) Hanson, Andrea R.
    Supplemental lipids and lipid rich ingredients with high concentrations of polyunsaturated fatty acids may peroxidize during processing and storage. Exposure to heat, air, moisture, and other pro-oxidants accelerate peroxidation, and peroxidation is impeded by antioxidants. Metabolic oxidative stress occurs when pro-oxidants overload the antioxidant capacity of an animal. This dissertation explores the impact of lipid peroxidation in DDGS and corn oil on the growth performance, health, and metabolic oxidative status of young pigs. An extensive summary of published research revealed that feeding peroxidized lipids to pigs and broilers reduced growth, feed intake, and gain efficiency by 11.2, 7.5, and 4.3%, respectively, and resulted in metabolic oxidative stress. Similar, negative effects were confirmed in 2 additional experiments which evaluated increasing dietary levels of peroxidized corn oil. Our findings suggest the magnitude of reduction in growth depends on the conditions used to peroxidize corn oil. However, in a separate experiment, the dietary inclusion of a highly peroxidized source of DDGS did not affect the growth performance of nursery pigs. Numerous compounds are produced and degraded during peroxidation, and some of these products have been associated negatively animal health and performance. The dynamic nature of peroxidation creates a challenge for nutritionists and formulators assessing the feeding value of dietary lipids. An in vitro experiment was conducted to compare several indicators of peroxidation when heating refined corn oil at either 185°C or 95°C. Results suggest that thermal processing and storage conditions should be considered when selecting indicators of peroxidation, but this information is seldom available. An additional experiment was conducted to assess peroxidation in distillers corn oil and DDGS during storage in the presence or absence of antioxidants. Peroxidation increased during 28 d of storage at 38°C and 90% relative humidity. However, peroxidation was attenuated partially by antioxidants. Our results clearly demonstrate negative effects of dietary peroxidized lipids on the growth performance and metabolic oxidative status of nursery pigs. Future research is necessary to develop an accurate model for predicting reductions in growth performance and metabolic oxidative status when feeding diets containing peroxidized lipids.
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    Improving the functionality and bioactivity of wheat bran.
    (2012-04) Petrofsky, Keith Eric
    Wheat bran, including the aleurone layer, contains the vast majority of phenolic antioxidants found in the wheat kernel. Unfortunately, about 80% of phenolic acids in wheat bran are structurally bound and insoluble. These bound phenolics are neither bioactive nor bioavailable during digestion. Additionally, wheat bran contains 43% total dietary fiber, but only 3% soluble dietary fiber. Insoluble fiber is less functional than soluble fiber which has been shown to lower cholesterol and regulate blood sugar. We hypothesized that processing could improve the functionality of wheat bran and bioavailability of phytochemicals in the bran. Specifically, we aimed to maximize the physical properties of viscosity and water hydration capacity in wheat bran, while also maximizing the release of bound phenolic antioxidants from the bran. Wheat bran processing included physical treatments of dry grinding, high shear mixing, high pressure homogenization (HPH), and alkali chemical treatments with different concentration, time, and temperature. Sample analysis included particle size, Wheat bran, including the aleurone layer, contains the vast majority of phenolic antioxidants found in the wheat kernel. Unfortunately, about 80% of phenolic acids in wheat bran are structurally bound and insoluble. These bound phenolics are neither bioactive nor bioavailable during digestion. Additionally, wheat bran contains 43% total dietary fiber, but only 3% soluble dietary fiber. Insoluble fiber is less functional than soluble fiber which has been shown to lower cholesterol and regulate blood sugar. We hypothesized that processing could improve the functionality of wheat bran and bioavailability of phytochemicals in the bran. Specifically, we aimed to maximize the physical properties of viscosity and water hydration capacity in wheat bran, while also maximizing the release of bound phenolic antioxidants from the bran. Wheat bran processing included physical treatments of dry grinding, high shear mixing, high pressure homogenization (HPH), and alkali chemical treatments with different concentration, time, and temperature. Sample analysis included particle size, viscosity, water hydration capacity (WHC), water extractable material (Wa-Ex), free phenolics, and visual imaging by scanning electron microscopy (SEM). Prescreening results showed that while HPH helped reduce particle size of bran regardless of treatment, only alkali chemical treatments released the vast majority of bound phenolics. Alkali treatments also contributed to viscosity increase, with interaction of variables of alkali concentration, treatment time, and temperature. Variables for optimization studies included bran grind, alkali concentration, reaction time, and reaction temperature, while process treatments that remained constant were high shear mixing after chemical pretreatment and HPH conditions. Two factorial designs were conducted to optimize viscosity and WHC of bran while maximizing release of bound phenolics. The second factorial design was an augmentation to the first and data was combined for statistical analysis. Viscosity maximum was reached using 0.5mm screen size in bran dry grinding and chemical treatment conditions of 60°C soak temp, 24 hour soak time, 0.1N NaOH concentration. WHC maximum was reached using 0.5mm screen size in bran dry grinding and chemical treatment conditions of 48°C soak temp, 20 hour soak time, 0.7N NaOH concentration. Overall, process optimization was successful and produced wheat bran with a 500% increase in viscosity, 200% increase in WHC, 500% increase in soluble fiber, and a 300 fold increase in free and soluble bound phenolic antioxidants. Visual confirmation by SEM validated analysis results and showed the optimized bran had a very open and porous structure due to the chemical weakening of the alkali treatment and high shear pulverization of the HPH treatment. The optimized viscosity process was scaled up to produce a large quantity of samples for further research in this collaborative study. Work to separate or concentrate the soluble fraction of processed bran utilized centrifugation to produce additional samples of more soluble and more insoluble processed bran fractions.
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    Manganese superoxide dismutase and cardiovascular aging phenotypes in mice
    (2012-09) Ross, Carolyn Marie
    Reactive oxygen species (ROS) have been implicated in the pathogenesis of a number of cardiovascular diseases. Furthermore, recent data from in vitro model systems suggests that mitochondrial ROS production may initiate a vicious cycle termed ROS-induced ROS-release (RI-RR). Whether this phenomenon occurs in vivo or is amplified by aging is not known. We hypothesized that induction of RI-RR by experimentally reducing manganese superoxide dismutase (a mitochondrial antioxidant enzyme) impairs aortic endothelial function and aortic valve function with aging, and that these functional changes would be associated with transcriptional repression of sirtuin family genes, which are known to be associated with aging and age-related diseases. For our studies, we used young (2 mo) and old (>18 mo) MnSOD wild-type (WT) and MnSOD-deficient (HET) mice. In aorta, increasing age significantly impaired vasomotor function (isolated organ chamber baths) in WT mice, but endothelial function was not further impaired in HET mice. Inhibition of NAD(P)H oxidase significantly improved endothelial function in aged WT mice. NAD(P)H oxidase inhibition in HET mice, however, paradoxically worsened endothelial function in young and old animals. Aortic valve function (echocardiography) was unaffected by aging in both WT and HET mice. Interestingly, expression of antioxidant enzymes and multiple sirtuin isoforms (quantitative real-time RT-PCR) were slightly reduced by aging in aorta, but were dramatically reduced in aortic valve. These transcriptional changes were not amplified in either aorta or aortic valve from HET mice. Collectively, our data demonstrate that the transcriptional responses and phenotypes elicited by aging and alterations in mitochondrial antioxidant capacity differ dramatically between aorta and aortic valve. We conclude that reductions in mitochondrial antioxidant capacity do not independently contribute to development of overt cardiovascular disease, and instead suggest that oxidative stress may play a modulatory role in cellular and organismal responses to pathophysiological stimuli that drive age-related cardiovascular disease.