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Department of Food Science and Human Nutrition

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This digital collection includes theses and dissertations from the Department of Food Science and Human Nutrition.

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Browsing Department of Food Science and Human Nutrition by Author "Avens, John S., committee member"

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    Effects of dark malts, dry hopping, and filtration on xanthohumol content and bioactivity of American India Pale Ales
    (Colorado State University. Libraries, 2011) Henley, Twila Jean, author; Stone, Martha, advisor; Vanamala, Jairam, advisor; Bunning, Marisa Lee, 1954-, committee member; Avens, John S., committee member; Reddivari, Lavanya, committee member; Stonaker, Frank H., committee member
    Xanthohumol (XN), a prenylated chalcone found in hops (Humulus lupulus L.) has been shown to possess a wide spectrum of beneficial properties including anti-oxidant, anti-proliferative, pro-apoptotic, anti-inflammatory, anti-bacterial, anti-viral, and anti-malarial activities. Efforts have been made to increase the amount of XN in beers by modifying certain brewing ingredients and procedures. However, the effects of modifications such as addition of dark malts, dry hopping, and DE filtration on XN content and the biological activity of American India Pale Ales (IPAs) are not known. In this study, different brands of IPAs with and without addition of dark/roasted malts, dry hopping, and filtration and one non IPA as a standard were analyzed for XN, isoxanthohumol, total phenolic content, and antioxidant capacity. Isolated beer compounds and selected whole beer matrixes were used to determine the synergistic effect of beer compounds on proliferation and apoptosis of HCT 116 p53 +/+ colon cancer cells. No XN was found in the standard, and the XN content in IPAs ranged from 0.00 to 12.69 mg/L. A heavily dry hopped IPA made with increased amounts of dark malt contained higher amounts of XN compared to other IPAs. The use of dark malts was protective against the removal of XN and other phenolics after diatomaceous earth (DE) filtration and dry hopping increased XN content in beer. Whole beer matrixes with greater levels of XN suppressed proliferation and elevated apoptosis in colon cancer cells compared with isolated XN and/or IX, indicating that the biological effect of XN can be bolstered in the presence of other beer compounds.
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    The effect of hop extract supplementation on gut microbiota and metabolic function in ovariectomized mice
    (Colorado State University. Libraries, 2017) Hamm, Alison Kay, author; Weir, Tiffany L., advisor; Cox-York, Kimberly A., committee member; Broeckling, Corey D., committee member; Avens, John S., committee member; Bunning, Marisa L., committee member
    Estrogen decline with aging, or menopause, is associated with increased risk for cardiometabolic diseases primarily due to altered metabolism and weight gain. Standard treatment has traditionally been with 17β-estradiol (E2) prescription, although its use has declined over the last decade due to associated increase in breast and ovarian cancer risk. As a result, use of phytoestrogenic herbal supplements has increased, due to their perceived safety and effectiveness in treatment of menopausal side effects. The gut microbiota may also be important in terms of mitigating disease risk and hormone exposure during the menopause transition, as our gut microbiota are important modulators of local and systemic inflammation. Gut microbes also can metabolize hormones and dietary flavonoids, altering their bioactivity and bioavailability. In this study, we supplemented ovariectomized (OVX) or control sham-operated C57BL/6 mice, with oral E2, a flavonoid-rich extract from hops (Humulus lupulus), or placebo carrier oil, and observed differences in adiposity, inflammation, and gut bacteria composition. Hops extract (HE) did not protect against ovariectomy-associated weight gain or increased visceral adiposity, while E2-treated animals had similar body weights and fat depot sizes as Sham-operated animals. However, HE was protective against liver triglyceride accumulation, to levels similar to Sham control and OVX E2 groups. We found no evidence of OVX having a significant impact on the overall gut bacterial community structure in any of our treatment groups. We did find differences in abundance of two bacteria; Akkermansia muciniphila was lower with HE treatment in the Sham group, and Ruminococcus gnavus was higher with OVX compared to Sham control. Possible mechanisms of the interplay between gut bacteria, loss of estrogen, and hormone replacement will be discussed.