Theses and Dissertations from UMD

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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

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Author: search.filters.author.Luther, Marla WestSubject: search.filters.subject.antioxidant

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    Promoting the production and consumption of wheat-based functional foods rich in antioxidants.
    (2008-11-20) Luther, Marla West; Yu, Liangli; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The present study evaluated the effects of solid state yeast treatment and thermal processing on the extractability and in-vitro bioavailability of antioxidants from wheat bran and whole-wheat pizza crusts, and developed sample outreach materials for promoting the consumption of whole-wheat functional foods. The first section analyzed the effect of solid-state yeast treatment on the extractable antioxidant properties of wheat bran. Wheat bran was treated with ten commercially available food grade yeasts under solid state conditions. Antioxidant properties were evaluated by measuring total phenolic content, and radical scavenging capacities against the cation ABTS, peroxyl (ORAC), DPPH (RDCS), and hydroxyl (HOSC) radicals. Results showed that under the selected conditions, yeast strain LBE.11 was able to increase ORAC and HOSC radical scavenging by 50% and 67%, respectively. The second part of this study evaluated the impact of bran particle size, fermentation time, and baking time and temperature on the 100% ethanol extractable antioxidant capacities of whole wheat pizza crust. Results showed that pizza crusts produced with reduced bran particle size maintained antioxidant capacity throughout thermal processing. At 18 hrs of fermentation RDSC and TPC values of the pizza crusts were increased by 17% and 23%, respectively. Increasing baking temperature increased RDSC values by 14 and 17% for pizza crusts prepared with Lakin and Trego variety wheat, respectively. The third part of this study analyzed the in-vitro bioavailability of wheat antioxidants in baked pizza crusts. Antioxidant properties were evaluated by measuring total phenolic content, and radical scavenging capacities against the cation ABTS, peroxyl (ORAC), DPPH (RDCS), and hydroxyl (HOSC) radicals. Pizza crusts with higher available antioxidants may have a greater level of bio-available antioxidants. The final segment of this research was to develop a tri-fold for promoting the consumption of whole wheat foods. The tri-fold was designed to include food-specific knowledge, consumption consequences knowledge in addition to recipes and directions, and nutritional facts. Integrating research findings into outreach materials may be an effective way to increase functional food consumption. Results from these studies indicate that there are numerous ways to increase antioxidant levels in the diet.
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    Inhibitory Effect of Selected Spice and Fruit Seed Extracts on Lipid Oxidation in Fish Oil and Their Radical Scavenging and Antimicrobial Properties
    (2006-09-27) Luther, Marla West; Yu, Liangli; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Ethanol extracts of cumun-3 parsley, black currant, green river parsley, Chardonnay grape, Pinot noir grape and black raspberry seed flours and cranberry seed meal were evaluated for their capacity to suppress lipid oxidation, preserve fatty acids, inhibit microbial growth, and scavenge DPPH and peroxyl radicals (ORAC), and total phenolic content (TPC). All tested extracts suppressed lipid oxidation in fish oil. At a concentration range of 2.6-5.3 mg flour or meal equivalents/mL all extracts exhibited antibacterial activity against Escherichia coli and Listeria monocytogenes, except cumun-3 and green river parsley against L. monocytogenes. All tested seed flour and meal extracts exhibited DPPH radical quenching activity. Chardonnay exhibited the strongest ORAC of 663 µmol TE/g and highest TPC of 99 mg GAE/g seed flour. The data from this study suggest the potential of developing natural food preservatives from these seed flours and meal for improving food stability, quality, safety and consumer acceptance.