Theses and Dissertations

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Open Access
Post-harvest treatment effects on quality and safety characteristics of melons and tomatoes
(Colorado State University. Libraries, 2008) Troxell, Heather LeAnne, author; Kendall, Patricia, advisor
Production, processing, and transport of high quality, safe, and healthful produce presents a constant challenge. Calcium chloride (CaCl2) dips have been shown to help maintain fruit quality after harvest by delaying senescence, reducing postharvest decay, and controlling many physiological disorders in fruit. There is little research available, however, assessing the effects of CaCl2 on sensory, nutritional, and microbial qualities of fresh, whole produce, including melons and tomatoes. This research project evaluated the impact of post-harvest storage temperature and use of a CaCl 2 dip on selected organoleptic, nutritional, and microbiological qualities of organic and conventional Colorado-grown melons and tomatoes over time. Melons (cultivars 'Haogen' and 'Arava') were grown on conventional and certified organic plats and tomatoes (cultivar 'Early Girl') were grown on certified organic plots during summer 2007 with controlled pre-harvest, harvest, and post-harvest conditions. All produce was picked at peak maturity and either dipped in a CaCl2 solution or not treated, then stored at 10° ±1° or 21° ±1° C. A variety of sensory, nutritional, and microbial tests were conducted on the fruit after storage for 1, 5, and 10 days. Storage temperature significantly impacted many of the fruit characteristics evaluated. Melons stored at 10° C had less microbial growth and higher sensory scores compared to the melons stored at 21° C. For tomatoes, many of the sensory and nutritional qualities were higher when stored at 21° C, even at 10 days storage. Use of a CaCl 2 dip treatment positively influenced (p<0.05) sensory scores for melons (appearance, texture, and overall acceptability) and tomatoes (flavor and overall acceptability). Overall, CaCl2 did not affect the fruits' antioxidant contents. When storing organic melons at 21° C, the CaCl 2-dipped melons had lower (p<0.05) Enterobacteriaceae bacterial counts compared to non-dipped melons. Based on this study, a CaCl2 treatment shows promise for increasing some safety and sensory characteristics of fresh melons and tomatoes, especially for produce stored at room temperature (21° C). Additional research should be conducted to further explore the potential of CaCl2 to lessen post-harvest expenses and losses while maximizing the sensory, nutritional, and safety characteristics of fruit.
Open Access
Cardiometabolic plasticity and skeletal muscle protein expression in Hispanic and non-Hispanic whites in response to a short-term diet and exercise intervention
(Colorado State University. Libraries, 2009) Schmidt, Stacy L., author; Melby, Chris, advisor; Hickey, Matt, advisor
The prevalence rates for type 2 diabetes (T2D) and the metabolic syndrome (MetS) have steadily increased to epidemic proportions over the past few decades, with disproportionately high rates of these health problems in Hispanics. The largest minority group in the United States is Hispanics, with Mexican Americans (MA) comprising the largest and fastest growing portion of the US Hispanic population. Insulin resistance is more prevalent in the MA population compared to other ethnic groups, and appears to precede many of the metabolic abnormalities involved in the progression toward T2D and MetS. Insulin resistance and many factors present in the MetS have been shown to improve following an increase in physical activity and consumption of diets low in saturated fatty acids and high in fiber. The overall objective of this project was to determine the combined effects of an increase in exercise combined with dietary lipid and carbohydrate modification on insulin sensitivity and blood lipids, and to determine if differences in expression of skeletal muscle proteins exist in non-obese, non-diabetic sedentary MA and NHW adults.
Open Access
Effects of the postprandial environment on the unfolded protein response
(Colorado State University. Libraries, 2009) Pfaffenbach, Kyle, author; Pagliassotti, Michael J., advisor
Background and specific aims. Newly synthesized proteins must undergo post-translational modifications such as folding and glycosylation to become fully functional. The lumen of the endoplasmic reticulum (ER) is a major site of protein folding and processing. The ER can respond to an increase in unfolded proteins (termed "ER stress") by activating the Unfolded Protein Response (UPR), a quality control mechanism which maintains ER homeostasis. Recent studies have demonstrated that the UPR is also involved in the regulation of a diverse array of cellular processes including glucose homeostasis, lipogenesis, and protein synthesis. The liver plays a central role in nutrient metabolism and maintaining glucose homeostasis. Further, in the postprandial state, both lipogenesis and protein synthesis are stimulated in the liver. However, the role of the UPR in the postprandial regulation of these processes has not been studied. Therefore, the first aim of the present study was to examine and characterize the regulation of the UPR in the postprandial state in the liver. One of the main rate limiting steps in protein synthesis is regulated by the mammalian target of rapamycin complex-I (mTORC I). Thus, the second aim of the current study was to examine the role of mTORC1 in the postprandial regulation of the UPR. Methods. Rats in Study 1 were fed a single starch or high sucrose meal and sacrificed either 1 or 7 hours post-feeding period. Plasma glucose and insulin were measured and hepatic tissue was examined for markers of UPR activation. Rats in Study 2 were injected with rapamycin, an inhibitor of mTORC1, prior to meal feeding. Rats were sacrificed 1 or 7 hours post-feeding period and blood and liver tissue were collected for analysis. To examine the role of insulin and glucose in the postprandial activation of the UPR H4IIE liver cells were exposed to varying amounts of glucose and insulin in the presence or absence of rapamycin. Results. Feeding activated select components of the UPR, including spliced X-box binding protein-1 (XBP1) and increased GRP78 and GRP94 mRNA expression. Rapamycin inhibited the postprandial increase of these components. The phosphorylation of eif2-Î± protein was not increased postprandially in the liver. Data from H4IIE cells demonstrate that insulin in the presence of glucose can activate UPR components in an mTORC1 dependent manner. Conclusion. The current study demonstrates that select components of the UPR are activated in the liver in the postprandial state. This activation appears to be insulin and mTORC1 dependent.
Open Access
The effects of moderate exercise on measures of postprandial lipemia
(Colorado State University. Libraries, 2009) Cox-York, Kimberly Ann, author; Horton, Tracy J., advisor; Pagliassotti, Michael, advisor
Background. Elevated triglycerides (TG) and small lipid particle size are risk factors for cardiovascular disease (CVD), which are typically assessed after an overnight fast. Most individuals spend the day in the postprandial (PP) state, however, which might be more reflective of CVD risk. A single exercise bout has been shown to decrease PP TGs in response to a single, high-fat meal. The current study assessed the effect of a single bout of morning exercise on PP lipids over an entire day with 3 mixed meals of a typical macronutrient composition (34% fat, 15% protein, 51% CHO). Methods. 26 normal weight (NW) subjects and 18 subjects with metabolic syndrome (MetS) were studied. After an overnight fast, subjects exercised (treadmill walking, 60%VO2peak) or rested for 60 min then consumed breakfast, lunch, and dinner, contributing 25%, 35% and 40% of daily energy intake respectively. Fasting blood samples were collected before exercise or rest and continued throughout the day and were analyzed for PP lipids, glucose and insulin. A subset of the plasma samples were separated into triglyceride-rich lipoprotein (TRL) subfractions in which TG and cholesterol were measured. Apolipoprotein (apo) B-100 and B-48 proteins were measured in the medium-sized subfraction (TRL2) to assess particle origin, size and composition. Postprandial responses were analyzed via ANOVA (SPSS 16.0). Results. Overall, exercise had no effect on PPTG. With exercise, total apoB IAUC decreased 20% in the whole group, and total cholesterol IAUC decreased 30% in the NW group. MetS subjects maintained significantly higher TG than NW subjects over the day (p<0.001). PPTG in MetS women declined mid-day, and remained low for the rest of the study day. In MetS men, however, PPTG rose consistently from breakfast, and then leveled out post-lunch and remained high. TRL particle size (TG:apoB ratio) was 30% lower in MetS women than MetS men. TRL2 apoB-100 and B-48 were twice as high in MetS as in NW subjects, resulting in significantly smaller particles in the MetS group (p=0.01). Conclusions. Although exercise did not have a significant effect on PPTG, there were other potentially cardio-protective effects on apoB and cholesterol levels.
Open Access
Evaluation of antioxidant and sensory properties of selected cultivars of Colorado-grown lettuce (Lactuca sativa L.)
(Colorado State University. Libraries, 2007) Bunning, Marisa, author; Kendall, Patricia, advisor; Stushnoff, Cecil, advisor
Epidemiological evidence has substantiated the health benefits associated with the consumption of vegetables, particularly leafy greens. Lettuce (Lactuca sativa L.) cultivars (varieties) have usually been selected based on shelf-life, transportability, and yield rather than nutritional or sensory traits. Information on the effects of seasonality and genetics on various characteristics of lettuce is limited. Nutritional, antioxidant, and sensory profiles of lettuce may vary considerably among cultivars and in response to environmental factors that may fluctuate widely throughout the growing season. Bitterness, an important flavor characteristic of lettuce, is generally thought to increase with higher growing season temperatures and may vary with phenolic content.
Open Access
Food as a visual cue: an analysis of perception, behavior and neural activity
(Colorado State University. Libraries, 2009) Burger, Kyle S., author; Johnson, Susan L., advisor; Pagliassotti, Mike, advisor
Intake regulation is a complex process impacted by a number of factors such as homeostatic, environmental and hedonic influences. Previous models of intake regulation tend to not take into account the large influence that the environment (e.g., visual cues) has on eating behavior. Little work has been completed that evaluates the interrelationship of environment, psychology and physiology relations' to eating behavior. A new model of intake regulation, including aspects of environment, psychology and physiology serves as the basis for this investigation. A series of three studies were completed. The first study evaluated the effect of visual cues i.e., portion size and blindfolding on energy intake. The second study used a computer program to assess individuals' subjective hedonic ratings (i.e., liking and wanting) of food images. The third study used neuroimaging to evaluate individuals' brain activity in response to food images. The first study demonstrated that energy intake increased 26% and bite size increased 2.3g/bite in response to presentation to a large portion. This was driven by overweight individuals. No portion by blindfolding interaction was found, indicating that blindfolding did not attenuate the portion size effect. It was observed in the second study that ratings for wanting were consistently higher that ratings for liking and fruits were the highest rated foods. In addition, in a fed state, overweight individuals rated large portions of food higher smaller portions of food for wanting, but not liking. Ratings for liking were related to activation of the posterior cingulate (decision making). It was also observed that dietary restraint was related to suppression of activity in the anterior cingulate (food reward). An increase in portion size appears to impact overweight individuals' energy intake (which occurs via changes in bite size) and ratings for wanting. A positive energy state could affect ratings for wanting but not liking. This decrease in wanting could be interpreted as dietary restraint which might function by decreasing brain activity in food reward related regions. Studying a comprehensive model including of intake environment, perception, behavior and physiology provides valuable insight to the interrelationship of all of eating behavior.
Open Access
Diabetes education in Oman: needs assessment and development of an intervention for health care professionals
(Colorado State University. Libraries, 2007) Al-Subhi, Lyutha Khalfan, author; Kendall, Patricia, advisor; Adams, Elizabeth, advisor
Oman is one of the countries faced with the challenge of an increasing rate of diabetes. The National Diabetes Control Program (NDCP), in Oman, aims to provide a suitable and quality health education to people with diabetes and the community. Diabetes management guidelines for Primary Health Care (PHC) in Oman point out that all members of the diabetes health care team share the responsibility of educating those with diabetes. Nevertheless, diabetes education has not been tackled systematically and the incidence of diabetes is on the rise in Oman. There is a pressing need for a diabetes education program for diabetes self management in the Sultanate of Oman.
Open Access
Edible mealworms: can fermentation improve consumer acceptability and nutritional value?
(Colorado State University. Libraries, 2023) Wilson, John W., author; Weir, Tiffany, advisor; Bunning, Marisa, committee member; Stull, Valerie, committee member; Nair, Mahesh, committee member
As the global population increases, the demand for animal-based protein is also on the rise. To meet this demand, it is important to identify sustainable sources of animal protein that have a smaller environmental impact than conventional animal protein production. One potential solution to this challenge is the development of consumer-acceptable insect-based protein products utilizing the larva and pupae of Tenebrio molitor, a type of darkling beetle whose larval and pupal states are edible. These beetles can be reared in small spaces, do not require direct sources of fresh water, and convert feed into protein more efficiently than conventional meat production. In addition, their waste (frass) is dry, making it easier to contain than waste from conventional animal rearing operations, reducing the risk of contaminating the surrounding environment. In addition, the larvae and pupae can be eaten in their entirety, eliminating potential waste streams of byproducts associated with conventional meat processing. With less space, less water usage, more efficient feed conversion ratios, and nearly zero waste, the development of an edible mealworm industry in the global West would help relieve some of the pressures on the current animal protein systems and improve global food security. To accomplish this, it is necessary to generate a consistent demand in the global West for insect protein. Currently, in the United States, edible insects are largely relegated to ground powders designed to "hide" the insects or are placed in novelty products like chocolates and lollipops to confront people's notion of disgust. To introduce mealworm protein into the mainstream, it must be in a form that is accessible to the average American consumer, be safe to eat, and have comparable nutritional attributes as other protein-based products on the market. Tempeh fermentation techniques may be an appropriate approach to accomplish these goals. Tempeh fermentation uses Rhizopus oligosporus mycelium to knit together legumes into a solid cohesive substrate. The product can then be utilized in a variety of ways that are familiar to American consumers including stir frys, burgers, nuggets, and crumbles. This project seeks to utilize tempeh fermentation techniques to develop an insect-based product that is both consumer-friendly but also capitalizes on the known and emerging nutritional and environmental benefits of edible insects. In Chapter 1, I examine the safety of tempeh produced with various life stages of the Tenebrio molitor beetle. Samples were assessed for water activity (aw), and pH to determine the shelf stability of the products. Pathogenic risk was assessed through testing for coliforms, Salmonella and Listeria, and samples were analyzed for heavy meatal content via utilized Inductively Coupled Plasma and Mass Spectrometry (ICP-MS). This exploration allows us to determine best storing and cooking methods and helps identify critical control points in production to help minimize the risk to the consumer. In this chapter, I was able to demonstrate that tempeh made with Tenebrio molitor was just as safe as conventional soy-based tempeh and requires similar storage and cooking precautions to minimize the risks of consumption. In Chapter 2 we conducted a nutritional analysis of the insect-based tempeh products in comparison to traditional soy-based tempeh. We utilized ICP-MS to quantify the presence of micronutrients within each example. Samples were also analyzed for vitamins, macronutrients, and amino acid profile. We then calculated the protein digestibility using the Protein Digestibility-Corrected Amino Acid Score (PDCAAS). Comparison of results with traditional soy-tempeh products helps us to determine if the products provide comparable nutrition to products already on the market. It also helps to determine if the novel products will fill the nutritional space of more conventional sources of protein. This chapter found that the tempeh products made with the Tenebrio molitor had nutritional attributes comparable to conventional soy tempeh. Chapter 3 examines the bioavailability of iron within the sample set and compare the results to conventional bee samples, current on-the-market plant-based meat alternatives, and traditional soy-based tempeh. ICP-MS was utilized to quantify the amounts of iron present in each chemically digested sample. Then, digestates were added to Caco-2 human colonic cells to allow absorption of available iron. Iron absorption rates were then determined by using a human ferritin Eliza kit. This assessment helps us determine if the presence of insect protein improves the bioavailability of iron in a traditionally plant-based food and allows us to compare the availability of the iron in the novel products to conventional beef and current plant-based meat products. The bioavailability of iron in the novel products exceeded that of the conventional beef and the plant-based meat alternative. In Chapter 4, we conducted a consumer acceptability study to analyze the potential for consumer acceptance of a tempeh product made with 50% mealworms and 50% soybeans when compared to a commercial soy-based tempeh. An online survey was conducted to assess the public's attitudes to entomophagy, their current level of exposure to the practice, and the willingness to consume insects. Next, the mealworm soybean tempeh was evaluated by a trained sensory panel to develop a lexicon that describes the organoleptic attributes of the product. Finally, a blind in-person sensory evaluation was conducted to assess the overall acceptability of the product. During the in-person evaluation, participants were provided with different prompts to determine if details around the environmental impact of insect eating versus conventional meat production would affect the favorability of the product. Participants in this study rated the flavor equal to that of the commercial soy tempeh and majority of participants indicated they were equally or more likely to consume insect-based products again. The final chapter explores the need for research around branding and availability on insect-based food products to increase acceptance of entomophagy in Western society. This dissertation aims to determine the safety of utilizing edible insects in tempeh fermentation, examine the nutritional attributes of tempeh products made with various life stages of the Tenebrio molitor beetle, determine how effective these products are in filling their intended nutritional niches, and assess the potential for consumer acceptance of insect-based tempeh products. This dissertation provides a strong foundation for the understanding of the safety, nutrition, and acceptability of utilizing T. molitor-based tempeh as an alternative source of protein.
Open Access
Promoting the consumption of beans and other pulses for public health: a translational approach to address consumer barriers to intake
(Colorado State University. Libraries, 2023) Didinger, Chelsea, author; Foster, Michelle, advisor; Bunning, Marisa, advisor; Thompson, Henry, committee member; Jablonski, Becca, committee member
Beans and other pulses (i.e., the dry, edible seeds of non-oilseed legumes like chickpeas, cowpeas, dry beans, dry peas, and lentils) are linked to a myriad of positive impacts on human and environmental health, including promotion of gut health and healthy weight management, reduction of chronic disease risk, mitigation of greenhouse gas emissions, improvements in soil health, conservation of water resources, and more. Moreover, pulses are highly nutrient-dense, have a long shelf-life, demonstrate wide culinary versatility, and are relatively affordable compared to other foods. Accordingly, pulses offer the chance to consume a healthful diet based on sustainable food choices, all at an economical price point. Although this combination of positive assets may make pulses seem like a natural choice for consumers to include as a dietary staple, global consumption of pulses has stagnated at around 21 g/day/capita. This research focuses on United States consumers, who eat less than 1 cup of cooked pulses per week, which is below the recommendation. According to the Dietary Guidelines for Americans (DGA), there are only four dietary components of public health concern (i.e., nutrients or other dietary components – like fiber – for which low intakes are associated with health concerns) in the United States. Among these four dietary components of public health concern are dietary fiber and potassium. Pulses are rich in both, thus increasing intake across the population could contribute to raising levels of these critical dietary components. Although it depends on age group and gender, the levels of pulse intake recommended by the DGA are around 1 – 3 cups per week. Increasing intake to meet this recommendation would help provide adequate levels of dietary components of public health concern. Raising it even further, to around 1 cup per day, has been associated with numerous human health benefits, as discussed in the Introduction. Reversing the current trend of dramatically low consumption would allow the public to better capitalize on all the benefits that pulses have to offer. To achieve this, it is vital to address the potential barriers to pulse intake that consumers face, paramount among them being unfamiliarity with how to cook and prepare pulses, long cooking times, and concerns over flatulence. Simultaneously, it is key to highlight the many motivating factors to eat pulses, including taste and culinary versatility, nutrition and health, and environmental benefits. Through engaging in a translational approach that addresses barriers and emphasizes motivators, not only is knowledge disseminated, but consumers can be motivated to engage in behavior change and increase their pulse consumption. This research is comprised of three primary efforts designed to directly target motivators and mitigate barriers to pulse consumption in the United States: 1.) creation of an Extension Bean Toolkit, which includes various consumer resources and an online 1-hour class; 2.) development of the Bean Cuisine and engagement with citizen scientists to improve the cuisine and monitor impacts of participation; and 3.) testing of the effects of elevation and soaking conditions on bean cooking time to address the concern over long cooking times and provide consumers with accessible cooking tips. Before designing the Extension Bean Toolkit, a Food Habits Survey was conducted to better understand preparation and consumption habits, barriers, motivators, and potential points of consumer interest related to pulses. Based on results and in conjunction with review of the literature, resources were developed for the toolkit, as well as the 1-hour class, titled Beans: Good for You, Good for the Planet. Participation in the class resulted in significant gains in knowledge about pulses, an increase in the importance of motivators, a decrease in how much barriers discourage consumers, and consumption frequency also appeared to increase. See Chapter 2 for details. The Bean Cuisine is a 2-week cuisine (i.e., meal plan) with 56 pulse-centric recipes that correspond to 14 unique breakfast, lunch, snack, and dinner ideas. The Bean Cuisine was designed to have 35% of dietary protein from pulses, due to recent preclinical findings that suggest this level of consumption is when benefits for gut health and weight maintenance are attained. The main barrier addressed was lack of awareness of how to cook and prepare pulses, and culinary versatility was a main motivator. Fifty-six citizen scientists were recruited and provided feedback on one day (i.e., four recipes) of the Bean Cuisine, and impacts of participation were monitored. The Bean Cuisine was modified based on their feedback to improve the recipes to ensure they were clearly written and the taste would appeal to a wider audience. Participation in the project resulted in significant gains in knowledge about pulse health benefits, versatility, and how to cook dry pulses. Moreover, common themes in free response data demonstrated that citizen scientists had increased awareness of pulse variety and versatility, they changed the frequency of and ways in which they ate pulses, they had a positive experience and thus a good perception of citizen science, and that some became pulse advocates, sharing the benefits of pulses with their communities. More details can be found in Chapter 3. Not knowing how to cook dry pulses and the long cooking times pose barriers to regular pulse intake. Therefore, to be able to provide consumers with better information regarding the effects of cooking conditions and elevation on cooking time, a Mattson cooker was used to assess the cooking time of pinto beans at four locations, ranging from around sea level to over 3,000 meters. Seven different cooking conditions were evaluated in replicate at each location: an overnight soak or a quick soak in only water or in a 1% solution of sodium chloride or sodium bicarbonate, with a no soak and no salt added comparison. Cooking time increased with elevation, and both the soaking of beans and the addition of salt shortened cooking time. A handout was created to equip consumers with information and practical, accessible tips to facilitate faster, better experiences when cooking dry pulses. Refer to Chapter 4 for details. Through the Extension Bean Toolkit and Bean Cuisine citizen science work, a translational approach was adopted to reach the public with current research findings that aligned with areas in which they expressed interest. The mitigation of potential barriers to pulse intake and the highlighting of the numerous benefits of pulses was a primary focus in this work. After participating in the Extension class or citizen science project, participants demonstrated greater knowledge about pulses. More importantly, they expressed a greater intention to eat pulses, indicating that participation in these translational projects helped motivate them to change their behavior and regularly integrate more pulses into their diets.
Embargo
Molecular and sociocultural exploration of sourdough: impacts on gluten sensitivity and bread characteristics
(Colorado State University. Libraries, 2023) Clark, Caitlin, author; Van Buiten, Charlene, advisor; Stone, Martha, committee member; Weir, Tiffany, committee member; Gentile, Chris, committee member; Prenni, Jessica, committee member
Sourdough is a bread product fermented by communities of wild bacteria and fungi known as a starter culture. Previous work has examined the effects of specific starter organisms on bread quality, but the relationships between whole microbiomes and dough/bread physicochemical properties are currently unknown. The objective of this study was to investigate the relationship between physicochemical properties of sourdough breads and the microbiomes of their starter cultures. Twenty sourdough starters with characterized microbiomes were used to produce wheat-based dough and bread. The chemical properties (pH, titratable acidity, free amino acids, Aw) of dough and physical properties (loaf volume, crust color, texture) of the breads were compared to a control fermented with baker's yeast. The degradation and toxicity of gliadin resulting from fermentation with the sourdough samples was also studied in vitro. Results indicate that sourdough-fermented breads produced under real-world conditions are distinct from yeast-fermented bread in terms of physicochemical parameters and proteolysis, which may exert downstream effects on the inflammatory capacity of gluten. We also investigated the beliefs and behaviors of gluten-sensitive sourdough consumers and professional sourdough bakers. We found that commercial sourdough is not reported to relieve gluten-mediated symptoms for consumers diagnosed with celiac disease (CD) or non-celiac gluten sensitivity (NCGS), but undiagnosed (UD) gluten-sensitive consumers may benefit from it. We also determined that sourdough bakers act as brokers of health advice in the gluten-sensitive community.
Embargo
Cardiovascular-protective effects of blueberry consumption in postmenopausal women with above-normal blood pressure
(Colorado State University. Libraries, 2023) Woolf, Emily K., author; Johnson, Sarah A., advisor; Gentile, Christopher L., committee member; Weir, Tiffany L., committee member; Rao, Sangeeta, committee member
Endothelial dysfunction is the first step in atherosclerosis and contributes to its progression, and thus, is central to cardiovascular disease (CVD). It is driven by excessive oxidative stress and inflammation and characterized by impaired endothelium-dependent dilation. Estrogen-deficient postmenopausal women have oxidative stress-mediated suppression of endothelial function that is worsened by high blood pressure. Chronic blueberry consumption may be a beneficial dietary intervention for this population as it has shown to improve vascular function and blood pressure, though some studies have not demonstrated efficacy possibly due to the observed high interindividual variability in response to the intervention. Evidence indicates blueberries improve endothelial function, but studies have not been performed in postmenopausal women. Furthermore, ex vivo research has shown that blueberry (poly)phenols and their metabolites can decrease endothelial oxidative stress and inflammation, but whether these mechanisms translate to humans is unclear. The objectives of this dissertation were to 1) examine the efficacy of chronic blueberry consumption to improve endothelial function and blood pressure in estrogen-deficient postmenopausal women with above-normal blood pressure, with a specific focus on identifying mechanisms for improving endothelial function, 2) identify factors that contributed to the efficacy of blueberries as a dietary intervention for improving endothelial function, and 3) explore cellular mechanisms responsible for endothelial function improvements and the anti-atherogenic potential of blueberries. To investigate the aforementioned, we conducted a randomized, double-blind, placebo-controlled clinical trial and assessed endothelial function (measured through flow-mediated dilation (FMD)) and supine brachial blood pressure before and after daily consumption of 22 g of freeze-dried highbush blueberry powder or isocaloric placebo powder for 12 weeks. To examine mechanisms for improved endothelial function, FMD was assessed before and after infusing a supraphysiological dose of the antioxidant ascorbic acid (i.e. vitamin C) and normalized to shear rate area under the curve (FMD/SRAUC). To investigate factors impacting the interindividual variability in the endothelial function responses after the 12 weeks of blueberry consumption, we grouped the blueberry treatment group into responders (≥ +1% unit Δ FMD) and non-responders (< +1% unit Δ FMD) and performed secondary statistical analyses using data produced from the clinical trial. Lastly, to investigate mechanisms for improvements in endothelial function, we used a reverse translational human-to-cell approach leveraging human blood serum collected from participants in the clinical trial to perform ex vivo cell culture experiments. Results from the clinical trial showed that daily blueberry consumption significantly improved FMD/SRAUC compared to baseline by 96%. FMD not normalized for shear rate increased by 1.34% though the effects were not statistically significant (but were clinically significant). Improvements in FMD/SRAUC after blueberry consumption were due to reductions in oxidative stress as responses to ascorbic acid infusion were significantly reduced at 12 weeks in the blueberry group compared to baseline, with no changes in the placebo group. There were no major effects on blood pressure, arterial stiffness, endothelial cell protein expression, or other blood biomarkers of cardiovascular health. It was determined that the blueberry intervention was ~50% effective for improving FMD to clinically relevant levels of ≥ +1%, and that responders had decreased cardiovascular health and higher levels of circulating estrogen at baseline compared to non-responders. After 12 weeks of blueberry consumption, responders had reductions in oxidative stress, lower plasma nitrate levels, and higher phosphorylated endothelial nitric oxide synthase protein expression compared to non-responders. Lastly, we cultured HAECs with 15% serum (blueberry and placebo) for 1 h followed by 200 µM hydrogen peroxide (H2O2) for 24 h to induce endothelial dysfunction and evaluated the effects of blueberry (poly)phenol-rich serum on endothelial cell dysfunction and atherosclerosis progression. There were no statistically significant differences on monocyte binding, insulin-stimulated nitric oxide production, or peroxynitrite concentrations between dysfunctional HAECs treated with blueberry and placebo serum from the clinical trial. Collectively, results from these studies indicate that daily blueberry consumption for 12 weeks improves endothelial function in postmenopausal women with above-normal blood pressure through reductions in oxidative stress, and that efficacy (i.e. degree to which postmenopausal women responded to treatment in endothelial function) seems to be dependent on participant characteristics including cardiovascular risk factors and estradiol at baseline. Due to the inconclusive results regarding the ex vivo experiment, cellular mechanisms by which blueberry (poly)phenol metabolites impact endothelial function and atherosclerosis progression cannot be determined.
Open Access
Medical student health behaviors and the influence on patient outcomes
(Colorado State University. Libraries, 2011) Jortberg, Bonnie, author; Harris, Mary, advisor; Cunningham-Sabo, Leslie, advisor; Kennedy, Catherine, committee member; Johnson, Susan, committee member
Purpose: Lifestyle habits are important risk factors for the development of cardiovascular disease, the leading cause of death in industrialized nations. The American Heart Association (AHA) and the National Cholesterol Education Program Adult Treatment Panel III (ATP III) recommend lifestyle changes as the primary and most cost-effective means of reducing the risk of coronary heart disease (CHD). Yet few physicians advise their patients about lifestyle modification. The main objective of this study was to determine if the nutrition and physical activity habits of medical students affect their patients' health behaviors on several important aspects of lifestyle modification: increased fruit, vegetable, and soy intake, and physical activity.
Open Access
Microbial quality of mixed salad greens and selected fresh and dried herbs
(Colorado State University. Libraries, 2010) Woo, Daniel Lee, author; Bunning, Marisa, advisor; Goodridge, Larry, committee member; Stone, Martha, committee member
Direct marketing has been growing in the Western U.S., with 2007 sales of direct-marketed agricultural products totaling nearly $142.6 million in Colorado, New Mexico, Oregon, Idaho, Nevada and Washington-more than twice the 1997 sales level for the region. In addition, the number of farms engaging in direct sales to consumers grew by more than 20% to 18,274 in 2007. With increasing foodborne outbreaks linked to produce consumption, more research is needed to fill in the gaps of knowledge on the microbiological quality of leafy salad greens. Limited research has been conducted on the microbial safety and quality of farmers' market leafy salad greens. This study surveyed the microbial quality of salad greens from Larimer County farmers' markets in conjunction with salad mixes from a local supermarket. Leafy salad greens were obtained weekly for a period of four weeks from September to October, 2009, from both farmers' markets and supermarkets. Total aerobic and coliform counts were assessed within 48 hours of obtaining the samples via plating onto Petrifilm plates, then following one week of storage at refrigeration temperatures to observe changes in the microbial load. In addition, handling methods and temperatures were also recorded. Gloves and tongs were not used by vendors when handling salad greens. The vendors surveyed also lacked adequate refrigeration or ice for holding salad greens. Farmers' market salad greens were lower than supermarket salad greens in terms of initial aerobic plate counts. Both farmers' market and supermarket salad greens had no detectable levels of Escherichia coli and low levels of coliforms. After 1 week of storage, aerobic counts were higher in all samples (P<0.05). Coliform counts tended to decrease in all samples but no significant differences were observed (P>0.05). The results reiterate the need for consumers to thoroughly wash their salad greens. Further research should be conducted to assess the microbial quality o~ other produce at local farmers' markets. Herbs are often used in cooking to add aroma and flavor to foods. Consumers may choose to dry herbs from their garden or purchased from the market. Herbs, like other agricultural produce, may be exposed to a wide range of potential microbial contamination. There is currently little research on safe drying practices of herbs at home. Microwaving herbs is a potentially popular and time-saving approach for drying herbs at home. This research project investigated the impact of three drying methods (microwave, dehydrator, and conventional air drying) for improving the microbial quality of dried parsley and cilantro. Herb samples were obtained weekly from a local supermarket for a 2 month period from January to March, 2010. Standard guidelines from Oregon State University Extension service were followed for microwave drying of herbs. The manufacturer's drying temperatures/times were used for drying herbs in a dehydrator. Herbs were also air-dried for 1 week. Microbial testing was performed using plating onto 3M Petrifilm and when counts were below the detection limit, via the Most Probable Number (MPN) method. Microwave drying provided the greatest reduction in aerobic counts of bacteria in herbs. All drying methods reduced coliform counts to undetectable amounts; however, the determination of the effectiveness of each drying method in comparison with others for reducing the coliform count was complicated by the low initial load of coliforms in herbs used in the study.
Open Access
Physicochemical modification of gliadin by black tea polyphenols: insight towards a nutraceutical therapy for celiac disease
(Colorado State University. Libraries, 2022) Mathews, Paul, author; Van Buiten, Charlene, advisor; Gentile, Chris, committee member; Chung, Jean, committee member
Celiac disease is an autoimmune disorder that affects approximately 1% of the global population. The pathogenesis of celiac disease is complex, involving the innate and adaptive immune responses. Exposure to gluten amongst genetically susceptible individuals initiates and propagates the disease process, with autoimmunity against endogenous tissue-transglutaminase enzymes manifesting intra- and extra-intestinal symptoms. Currently, the only mitigation strategy for celiac disease is an adherence to a gluten-free diet, which can be difficult to maintain. Recent advances in synthetic and natural products chemistry may offer therapeutic alternatives to the total abstinence from gluten containing products. The overarching objective of our research is to develop a nutraceutical approach to treating celiac disease using dietary polyphenols from tea. Within this thesis, we used a multi-spectroscopic approach to show that black tea polyphenols, which are rich in theaflavins and other flavanols, interact with gluten proteins in vitro to form colloidal complexes that result in structural change to the protein. These changes have the potential to reduce the immunogenicity of gluten via interference with digestion, sequestration, and conformational changes which may reduce recognition of the protein by immune cells. The interactions investigated here offer promise as a nutraceutical, plant-based therapy to acute gluten exposure in susceptible individuals.
Open Access
Characterization of protein-polyphenol interactions between novel plant proteins (pea and hemp) and blueberry polyphenols with respect to polyphenol binding and delivery
(Colorado State University. Libraries, 2022) Chima, Bianca, author; Van Buiten, Charlene, advisor; Johnson, Sarah, committee member; Prenni, Jessica, committee member
Despite the numerous health benefits associated with polyphenols, dietary intake of this class of compounds is low in the United States due to low intake of fruits and vegetables. It has been shown that dairy foods (i.e. milk, yogurt) increase polyphenol bioavailability due to polyphenols interacting with whey protein, enhancing polyphenol stability and uptake throughout digestion. However, increasing concerns for sustainability and health have introduced a variety of novel plant-based proteins as dairy alternatives. This study aimed to investigate the abilities of edible pea and hemp protein isolates to form complexes with blueberry polyphenol extract (BPE) and characterize the physical and biological functionalities of these complexes compared to whey proteins. Protein/polyphenol solutions were analyzed using UV-Vis spectroscopy to determine if complexation occurred. Secondary structures and binding affinities were analyzed by far-UV CD Spectroscopy and fluorimetry, respectively. In vitro digestion was performed to determine whether the protein profile changed in the presence of BPE via SDS-PAGE and determination of free amino acids using the ninhydrin method. Protein isolates from pea and hemp successfully formed complexes with BPE with binding affinities for the compound similar to whey protein. Relative helicity of the hemp protein was higher than the other protein sources and increased upon complexation with BPE. Furthermore, the SDS-PAGE profiles of all the proteins were the same whether BPE was present or not and the free amino acid content increased after digestion for the protein and protein/polyphenol solutions. Overall, complexation of BPE with plant proteins was successful. Fluorescence quenching and changes to the secondary structure of the proteins in the presence of BPE indicate that polyphenols were bound but the mechanisms and structures responsible for complexation seem to vary between proteins. More research is needed to determine the interactions that cause binding between the polyphenols and the proteins and whether the bioavailability of the compounds will increase when bound to the proteins in cell model and/or clinical study. This study provides a foundation for exploring the effects of plant-based proteins on phytochemical functionality in complex, "whole food" matrices.
Open Access
Assessing the attitudes of hospitality students towards the use of a classroom response system (CRS)
(Colorado State University. Libraries, 2010) Milholland, Eric Stanley, author; Miller, Jeff, advisor; Martin Gould, Susan, advisor; Hogler, Raymond, committee member
A Classroom Response System (CRS) is a technology instructors can use to promote active learning. Researchers have shown a number of benefits of CRS use, including anonymous student response, better attendance, increased peer instruction, higher test scores, better grades, and the ability to use contingent teaching methods. Compared to traditional methods, contingent teaching allows instructors to gain real-time understanding of what students know and comprehend. Instructors then can use CRS based feedback to employ learner-paced instruction. Previous researchers focused on CRS use in disciplines like math and physics. A literature review did not locate any previous studies about using CRS in hospitality education. Regardless of the course studied, researchers found CRS was most effective when used as a tool to reinforce sound pedagogy. This study investigated the attitudes of hospitality students regarding the technology. The study was conducted over a three semester period, and was comprised of hospitality students (n=l 17) in an introductory food science course in which a CRS was used. Students responded to additional statements on standard course evaluation surveys. Students also wrote comments about their CRS experience in this class. Survey responses indicated students felt CRS encouraged discussion and participation, helped reinforce course concepts, and increased class enjoyment. Additionally, students suggested using CRS in more of their hospitality courses and in more courses university-wide. Students written responses indicated similar opinions as the surveys. Students indicated CRS helped them understand concepts, engage in discussion, and motivated them to attend. Others said using the device was fun and would recommend it to other students and for other classes. The results showed hospitality students have an overall positive attitude regarding CRS. This research indicated hospitality educators may want to use this technology to enhance instruction. As future versions of the technology evolve to become even more interactive, additional research should be conducted to see how CRS use will change in the future.
Open Access
Rapid detection of viable escherichia coli O157:H7 by antimicrobial incorporated multi-angle light scattering spectroscopy
(Colorado State University. Libraries, 2010) León, Juan Carlos, author; Goodridge, Lawrence D., advisor; Bunning, Marisa, advisor; Nightingale, Kendra K., committee member
Escherichia coli 0157:H7 continues to cause outbreaks of produce-associated foodborne illness. Contaminated water has been shown to be a vehicle for transfer of E. coli 0157:H7 to leafy greens during irrigation. Timely detection of this pathogen in irrigation water can prevent contamination of the final product. Current detection methods which are culture-based can be labor intensive and require several days to produce results. There is a need for development of rapid detection methods, which can detect E. coli 0157:H7 in irrigation water. These methods have to be sensitive, robust and ideally should be able to differentiate between viable and non-viable microorganisms. Multi-angle light scattering spectroscopy (MAES) is a powerful technique that has been applied to qualitatively and quantitatively distinguish internal structural changes in cells upon perturbation by chemical/biological agents. We hypothesized that combining bacteriophage (phage) infection, which occurs only in viable bacterial cells, with MAES would allow for detection of the target bacteria and distinguish between viable and nonviable bacterial cells. The objective o f this study was to use E. co//-specific bacteriophages in conjunction with immunomagnetic separation and MAES to develop an assay for rapid detection of viable E. coli 0157:H7 in irrigation water. We have termed this new method Antimicrobial Incorporated Multi-angle Light Scattering (ANIMALS) to highlight the combination of a specific antimicrobial agent (phages) with the multi-angle light scattering technique to form a sensitive, rapid and specific assay for detection of E. coli 0157;H7. E. coli 0157:H7 and Salmonella Typhimurium strains were diluted in lambda buffer to form concentrations of 10*^ to lO"^ CFU/ml and 10*, respectively. The samples were subjected to immunomagnetic separation (IMS) using E. coli 0157-specific IMS beads. Following IMS, the beads (and attached bacteria) were resuspended in 1 ml of tryptic soy broth (TSB) and one half (500 pi) of each sample was added to 10 mis of TSB that contained 1 ml of phage ARl (lO'** PFU/ml). The other half of the samples were added to TSB that did not contain phage AR l, but contained 1 ml of lambda buffer (to maintain constant volume), and these samples served as a reference. The samples were incubated at 37° C, with shaking, for 15 hours. Following incubation, 100 pi aliquots were removed from each sample, and separately assayed using a SpectraPoint light scattering spectrometer (Spectra Digital Corp., Toronto, Ontario, Canada). E. coli 0157:H7 was detected in 100% of pure culture samples in TSB containing various concentration (10*^ to 10^) of the bacterium within 15 hours. An algorithm was developed to evaluate the area under the curve of each spectra. When compared to the light scattering spectra of the non-phage treated reference, the spectra o f phage infected E. coli 0157:H7 cells differed markedly. In contrast, the spectra of samples that contained Salmonella Typhimurium and the negative controls (containing no cells) were almost identical, because phage ARl does not infect Salmonella Typhimurim and there was no growth in the negative control samples, respectively. Using this method, E. coli 0157:H7 could be detected following 15 hours of incubation in samples spiked at an initial concentration of 10** CFU/ml. The sensitivity and specificity of the ANIMALS assay was determined using environmental water samples. River water samples were artificially contaminated with a 3-strain cocktail of E. coli 0157:H7, followed by IMS and incubation in TSB supplemented with 20 mg/ml novobiocin at 42° C. MALS measurements were taken at 4, 6, 8 and 10 hours. The means and standard deviations of the ratios o f the differences between the test and reference spectra for the four concentrations (10‘^ to 10^ CFU/ml) o f E. coli 0157;H7 were analyzed as well as for negative controls (samples o f river water that were not inoculated with E. coli 0157:H7). One concentration (10^ CFU/ml) of E. coli 0157:H7 was detected consistently after only 6 hours of enrichment. E. coli 0157:1-17 was consistently detected at concentrations from 10‘ to 10^ CFU/ml in spiked river water within 8 hours. All concentrations (10° to 10^ CFU/ml) were detected after 10 hours of enrichment. The presence of the pathogen in positive river water samples was confirmed by using lateral flow devices specific for E. coli 0157:H7. The negative controls resulted in negative readings. Additionally, reservoir water samples were prepared similarly to river water samples and MALS measurements were taken at 4, 6, 8 and 10 hours. The test and reference spectra for the four concentrations (10° to 10^ CFU/ml) of E. coli 0157:H7 were analyzed as well as for negative controls (samples o f reservoir water that were not inoculated with E. coli 0157:H7). Similar results to experiments on river water were obtained with 10^ concentrations of E. coli 0157:H7 detected consistently at 6 hours. This demonstrated that the ANIMALS assay worked consistently across water samples with different physical and chemical characteristics. Regardless, E. coli 0157:H7 was consistently detected in 100% of concentrations (10 to 10 CFU/ml) within 8 hours even against background levels of bacteria as high as 10^ CFU/ml. Lateral flow devices specific for E. coli 0157:H7 confirmed the presence of the pathogen in positive reservoir water samples. The negative controls resulted in negative readings. These results demonstrate the ability of ANIMALS to rapidly and sensitively detect the presence and viability of E. coli 0157:H7 following phage infection. This method has the potential to allow for rapid detection o f viable E. coli 0157:H7 in irrigation water against a high background o f non-target microorganisms if coupled with selective enrichment.
Open Access
The HEROs Self-Care Program: targeting maternal self-care in obesity prevention
(Colorado State University. Libraries, 2021) Hobbs, Savannah, author; Bellows, Laura, advisor; Johnson, Susan L., committee member; Coatsworth, Doug, committee member; Faw, Meara, committee member
Background: Obesity has continued to be a major health concern for adults and children in the United States, and maternal mindful self-care behaviors related to healthy eating, physical activity (PA), and stress management play an important role in child weight status, especially in early, formative years. Rural mothers, however, face unique barriers to these health behaviors. Objective: To design a mindful self-care intervention and investigate its feasibility and acceptability for mothers of preschoolers living in rural Colorado with limited resources. Methods: The Healthy EnviROnments (HEROs) Self-Care program was designed using Intervention Mapping and the Plan-Do-Study-Act (PDSA) model to integrate Social Cognitive Theory, effective behavior change strategies, and tailor the intervention to the audience contexts. The resulting program included 2 group workshops and 4 individual health coaching sessions via videoconferencing with topics on healthy eating, PA, stress management, and goal setting for health. Baseline health measures (weight status, cardiovascular disease (CVD) risk factors, and health behaviors) were gathered on participants (n = 23) at 3 health fairs to provide information on the health status of the target audience, and the intervention was piloted with a subsample (n = 6) to inform program feasibility (e.g., feasibility of data collection and program implementation). Post-intervention interviews informed program acceptability (e.g., components that functioned well and areas for further refinement). Results: Audience input informed the development of the HEROs Self-Care program, resulting in a theory-based intervention integrating best practices and consideration for audience-specific barriers to behavior change. The pilot outlined effective intervention strategies such as videoconferencing technology and individual health coaching sessions as well as future areas for refinement like additional healthy eating content and improved integration of mindfulness and digital supports. Baseline health measures did not meet recommendations, further indicating a need for a program to address maternal health. Conclusion: The HEROs Self-Care program was designed systematically to target maternal self-care as an approach for childhood obesity prevention efforts. Audience feedback and baseline health data supported the need for a maternal self-care intervention within childhood obesity interventions, and the intervention pilot revealed the program to be feasible and acceptable.
Open Access
Using participatory action research methods to create nutrition education that sustainably improves diet diversity through women's empowerment
(Colorado State University. Libraries, 2021) Sly, Brittney Catherine, author; Weir, Tiffany, advisor; Melby, Chris, advisor; Cunningham-Sabo, Leslie, committee member; Leisz, Stephen, committee member
Malnutrition is a major cause of morbidity and mortality for vulnerable sub-Saharan African populations, and despite decades-long efforts from global and regional organizations, the prevalence of malnutrition is not improving. Many programs fail to address the underlying causes of malnutrition within specific cultural and community contexts, particularly issues that contribute to malnutrition such as hygiene, agriculture, education, and poverty reduction. Therefore, there is a need for more sustainable, culturally inclusive, and targeted malnutrition remediation interventions that address the multifaceted issues involved with the rising numbers of malnourished people in sub-Saharan Africa. The purpose of this research was to develop a nutrition-sensitive agriculture intervention, aimed at sustainably increasing diet diversity and food security at the household level, in a rural Rwandan community, using Participatory Action Research (PAR) methods to empower women as peer educators. Small groups of women (n=42), divided into 6 groups of 7, collectively received agriculture trainings and nutrition education over the course of 16 weeks, along with the tools and support to start and maintain kitchen gardens. A large group session, using PAR methodology, was conducted to guide self-reflection and knowledge-assessment, while empowering women educators to spread information throughout their community. By coupling the intention of nutrition-sensitive agriculture with the empowering and inclusive methods of PAR, the goal was to provide the framework for establishing more sustainable nutrition-sensitive agriculture interventions, while encouraging the dissemination of information to the larger community. Collaborative community-based nutrition-sensitive agricultural interventions in rural, poor Rwandan populations can increase household diet diversity to encourage sustained change in dietary patterns for nutritional adequacy. Using kitchen gardens as the conduit for change, households can increase their consumption of home-grown vegetables, as well as other nutrient-dense foods. Additionally, employing PAR methods within the intervention design to enable participants to serve as active contributors and peer educators, enhanced women's empowerment and contributed to increased agency, as well as widespread information dissemination. However, more research concerning the systems that affect food availability and agricultural markets is needed to enact changes in food security, as well as more investigation into the ways in which empowerment influences the spread of information throughout a community.
Open Access
High elevation food preparation: consumer assessment and toolkit development
(Colorado State University. Libraries, 2021) Engelhardt, Heidi, author; Bunning, Marisa, advisor; Van Buiten, Charlene, committee member; Hyatt, Doreene, committee member
At higher elevations, reduced air pressure and dry conditions impact food preparation in a multitude of ways. The boiling point of water decreases, the rate of evaporation is higher, and the functionality of leavening agents can be altered. Cooks, bakers, and food scientists alike face challenges in adjusting processing methods and ingredients to ensure desirable results of recipes at various elevations. Current information on food preparation at high elevations lacks consistency and accessibility and often requires using multiple sources that may not be reliable. This leaves the home cook vulnerable to failed recipes and in some cases, foodborne illness. An assessment of consumer cooking, baking, and food preserving practices was needed to identify and prioritize information that could contribute to successful and safe food preparation at higher elevations. To assess these needs, a survey was developed, conducted, and results were analyzed to guide resource development for a high elevation food preparation toolkit. The purpose of the project was to construct useful materials as part of a set of tools to empower home cooks to apply research-based knowledge in Colorado and other high elevation locations in the United States. Developed resources included eight ingredient information sheets, a troubleshooting guide with suggestions for nine food products or methods. A set of presentation slides and two activities with pre- and post-evaluations to measure behavior change are included for county extension agents to use while engaging with their communities. Expanding awareness related to the impacts that higher elevations have on food preparation connects home cooks with food science as well as food safety. In addition to nutritional needs, food related pastimes often serve a greater purpose providing comfort and a rewarding way to cope with stress, promoting general well-being. Success in a high elevation kitchen would include recipes that do not fail as often, have desired taste and texture, and appropriately address food safety. This toolkit can be utilized in many different ways with the goal of helping consumers become more knowledgeable and successful when safely preparing foods at high elevation. We expect these materials to have national usefulness and aid in the development of skills that can be routinely incorporated in food preparation at higher elevations.