Nutrition & Food Science Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2798
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Item Chemical Compositions of the Selected Cold-pressed Seed Flours and Their Free Radical Scavenging and Anti-proliferative Capacities(2019) Song, Zhangyi; Yu, Liangli (Lucy); Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The cold-pressed blackberry, broccoli, carrot, cucumber, and milk thistle seed flours were extracted with 100% ethanol and examined for their phytochemical compositions, total phenolic contents, ABTS•+ and relative DPPH• scavenging capacities, and anti-proliferative activities in HCT116 and SW480 colon cancer cells. Eleven, eight, ten, and thirteen compounds were tentatively identified in the blackberry, broccoli, carrot, and milk thistle seed flour extracts, with ellagic acid, glucoraphanin, kaempferol-3-O-rutinoside, and silychristin isomers being the primary components in each, respectively. Milk thistle seed flour extract had the greatest total phenolic content. Blackberry seed flour extract possessed the strongest free radical scavenging capacities against both DPPH• and ABTS•+. Milk thistle seed flour extract was the only extract capable of significantly suppressing the growth of SW480 colon cancer cells, but not HCT116 cells.Item DESIGN, IMPLEMENTATION, AND EVALUATION OF A MINDFULNESS FOCUSED NUTRITION PROMOTION PROGRAM TO BALANCE USDA SCHOOL NUTRITION GOALS WITH FOOD WASTE REDUCTION IN ELEMENTARY SCHOOLS(2019) Schachtner-Appel, Amy Elizabeth; Song, Hee-Jung; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Healthy school meals offer numerous benefits for elementary school students, but low produce intake and high rates of waste prevent students from experiencing these benefits. This research aimed to create a mindful and sustainable eating intervention to encourage reduced waste and increased produce intake during lunch. The study was conducted using a mixed-methods triangulation approach for formative research, creation of a behavioral model to design a theory based intervention, and pilot test of the resulting program using a quasi-experimental controlled design. Formative findings, gathered from 50 3rd-5th grade focus group participants, 15 in-depth interviews with school staff, and 9 cafeteria observations supported the use of social cognitive theory (SCT) to explain eating behaviors and emphasized the importance of involving student leaders and creating environmental reinforcements. Pilot intervention approaches included delivery of an education curriculum, dissemination of messages by student leaders, cafeteria environment changes, and creation of a food recovery program. Measurements included observation of kindergarten – 5th grade lunches at baseline and follow-up (n = 162) to estimate foods selected, consumed, and wasted, survey of 3rd – 5th grade students at baseline and follow-up (n = 169) to measure psychosocial changes related to mindful and sustainable eating, and periodic food waste audits (n = 8) to monitor school-level plate waste. Baseline results showed students consumed only 36-42% of vegetables selected and 64-67% of fruit selected. At follow-up, intervention students selected more produce than controls (1.09 vs. 0.64 servings of vegetables; 1.32 vs. 1.06 servings of fruit). Similarly, they consumed more produce (0.51 vs. 0.33 servings of vegetables; 0.94 vs. 0.70 servings of fruit) than controls. Intervention students trended toward reduced vegetable waste while maintaining selection, whereas controls decreased selection substantially. Intervention students experienced significant increase in self-efficacy to base lunch choices on body cues. Higher produce consumption and lower waste were predicted by improved intentions to eat healthfully. Overall, the program successfully improved intake and trends indicate potential to reduce waste. Findings support expansion of the program, with potential to improve nutritional status of students and reduce the environmental impact of school meals.Item The Development of a Qualitative Risk Assessment and Targeted Storage Decline Kinetics Data as Critical Components for Developing a Full Quantitative Risk Assessment of Salmonella Contamination in Milk Chocolate(2019) Oni, Ruth Adeola; Buchanan, Robert L; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Salmonella enterica infections and outbreaks have been associated with chocolate consumption over the last four decades. The source of contamination for these occasional salmonellosis outbreaks are often unidentified, and typically the level of contamination is only a few salmonellae per serving. The main goals of this dissertation were to collate relevant scientific information regarding microbial safety of milk chocolate, conduct a qualitative assessment of risk factors for Salmonella contamination encountered during the complex processes of cocoa bean cultivation and the subsequent process of milk chocolate manufacturing, and to generate targeted data and survival models for kinetics of Salmonella stored in milk chocolate crumb; all components critical to the development of a stochastic quantitative microbial risk assessment. The farm-to-packaging qualitative assessment provided categorizations of risk for relevant activities and ingredients, identified critical data gaps and “risk spots” and culminated in an Excel-based risk rating tool used to illustrate the usability of the qualitative assessment. Results indicate an overall low residual risk of Salmonella contamination of a packaged milk chocolate product for a base model, provided dictates of process control measures are rigorously adhered to, and the risk rating tool enables the assessment of what-if scenarios for deviations from optimal practices. One of the data gaps identified in the qualitative risk assessment led to investigation into the use of milk chocolate crumb, an intermediate product during milk chocolate processing, and its potential association with Salmonella risk. Evaluation of the survival kinetics of S. enterica in milk crumb showed a significant (p<0.05) dependence of survival on storage temperature, strain and crumb type. Due to the manner in which crumb is generally utilized during milk chocolate processing, findings from this study are the first to link the use of crumb and Salmonella risk, and presents promising opportunities for risk reduction which can be explored through further research into optimization of crumb storage parameters. This study serves as a valuable resource to food safety stakeholders in the chocolate industry as it builds the foundation and provides much-needed data for a quantitative microbial risk assessment model that can be used to optimize food safety control programs.Item Identification of ESE-1 as a novel molecular target of chemopreventive agents for colon cancer prevention(2019) Lee, Jihye; Lee, Seong-Ho; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Epithelial specific ETS-1 (ESE-1) is one of the E26 transformation-specific transcription factor superfamily and could be considerable interest as a possible target for regulating diverse types of human cancer. Despite its clinical importance, the reported biological role of ESE-1 on cancer development and progression are still controversial and its underlying mechanisms of tumorigenesis remains unclear. The objectives of this dissertation are to elucidate the role of ESE-1 in tumorigenesis. With the evidence in cancer phenotypes, the underlying mechanisms of ESE-1 in colon cancer was also investigated. ESE-1 knockout mice increased azoxymethane (AOM) -induced and dextran sulfate sodium (DSS)-promoted formation of aberrant crypt foci (ACF) compared to wild type mice. Overexpression of ESE-1 suppressed anchorage-independent growth and migration/invasion in human colon cancer cells and while knockdown of ESE-1 reversed anti-cancer activity. Full length ESE-1 was abundantly found in the nucleus, and internal deletion of nuclear localization sequence 2 (NLS2) decreased the amount of nuclear ESE-1. Three lysine residues (318KKK320) in the NLS2 were critical for nuclear localization of ESE-1 and mediates tumor suppressive activity of ESE-1 through reduced beta-catenin transcriptional activity. We identified two anti-cancer natural compounds, epigallocatechin-3-gallate (EGCG) and patchouli alcohol as ESE-1 inducers. Both EGCG and patchouli alcohol increased expression of ESE-1 protein and mRNA in human colon cancer cells. Patchouli alcohol showed reduced the number of tumors and tumor load in Apcmin/+ colon cancer animal model although protein expression level of ESE-1 did not show significant difference. These findings suggest a potential use of ESE-1 as a novel and potential molecular target of natural anti-cancer phytochemicals for colon cancer prevention.Item Enhancement of Thermal Inactivation of Foodborne Pathogenic Bacteria at Mild Heating Temperatures with Inclusion of Butyl Paraben and the Application on Foods(2019) Gao, Zhujun; Buchanan, Robert L.; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Thermal processing is widely used in food industry to ensure the microbial safety, however, there is increasing demand on reducing the processing temperature and duration. This study specifically focused on mild heating temperatures (<60 °C) with inclusion of low level (≤ 125 ppm) of the approved preservative butyl-parahydroxy-benzoate (BPB). In a BHI model matrix, four pathogens were studied with submerged coil apparatus: Cronobacter sakazakii 607, Salmonella enterica serotype Typhimurium, attenuated Escherichia coli O157:H7 and Listeria monocytogenes. The results indicated that low concentrations of BPB combined with temperatures < 60 °C achieved 5 – 6 log reductions in less than 15 minutes with tested gram-negative microorganisms, whereas reductions without BPB were only 1 – 2 logs. We further extended the study to food applications: powdered infant formula, non-fat dry milk, and apple juice. The results indicate BPB will be inhibited by proteins, but apple juice is a suitable application.Item EVALUATION OF PUBLIC HEALTH RISK FOR ESCHERICHIA COLI O157:H7 IN CILANTRO(2019) Horr, Taryn; Pradhan, Albani; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The supply chain of cilantro was modeled for growth and die-off of Escherichia coli (E. coli) O157:H7 from infield and harvesting, transportation and storage and ultimately consumption at home. Using Visual Basic for Applications (VBA) macros and @RISK software, a simulation model was developed for exposure and estimation of illnesses. Test scenarios were modeled to determine the relative importance of different factors on the risk of illness. The developed model was simulated using Monte Carlo technique and Latin Hypercube sampling for 100,000 iterations. Results showed an increase in the mean E. coli O157:H7 concentration along the supply chain for cilantro grown in both winter and summer weather conditions. In the winter, the mean pathogen concentration increased from 5.6×10-5 CFU/g to 24.7 CFU/g from after harvest to after home storage, respectively. In summer conditions, the mean pathogen concentration increased from 3.2×10-4 CFU/g to 5.2×10-2 CFU/g. The inner quartile ranges (IQRs) for the same model conditions showed a decrease in E. coli O157:H7 concentration along the supply chain for cilantro grown in both winter and summer weather conditions. This indicates a majority of situations result in a decrease in E. coli O157:H7 concentration along the supply chain however rare situations can occur where the concentration will increase greatly. With a prevalence of 0.1% E. coli O157:H7 contamination for cilantro post-harvest used for illustration, the model predicted the mean number of illnesses per year due to the consumption of E. coli O157:H7 contaminated cilantro in the United States as 86 and 164 for cilantro grown during winter and summer conditions, respectively. Sensitivity analysis results indicated that transportation temperatures and quality of irrigation water had the largest impact on the number of illnesses per year. Scenario testing results for different risk factors demonstrated the importance of limiting and reducing cross contamination along the production chain, especially at higher initial prevalence levels and preventing temperature abuse during transportation from farm to retail, when reducing overall risk of illness. The developed risk model can be used to estimate the microbiological risks associated with E. coli O157:H7 in cilantro and determine areas along the supply chain with the most effect on the final concentration per serving for future mitigation strategies.Item Flavonoids, Cardiovascular Disease, and Diabetes(2019) Gahche, Jaime; Sahyoun, Nadine R; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Background: Flavonoids have been shown to have anti-inflammatory, antioxidant, and vasodilatory properties; mechanisms that may lead to cardio-protective benefits. Results from observational studies assessing the associations between flavonoid intake and cardiovascular disease (CVD) and type 2 diabetes mellitus have been largely equivocal. Earlier studies were limited due to lack of complete flavonoid composition databases. With the development of more complete databases, total flavonoid intake can be more accurately estimated, but the associations between them and CVD and diabetes have not been assessed in a nationally representative sample of the U.S. population. Aims: The objective of this study was to assess the relationship between dietary intake of flavonoids and risk of: 1) CVD outcomes, and 2) diabetes. Methods: Baseline data from the Third National Health and Nutrition Examination Survey (NHANES III) were collected from participants in 1988-1994 and linked with administrative records to identify CVD and diabetes outcomes. The National Death Index was used for mortality and CMS Medicare Claims and Medicare enrollment data to identify initial events. Flavonoid intake was assessed with up to four 24-hour dietary recalls and the USDA’s flavonoid databases were used to assign flavonoid values to reported food and beverage consumption. Usual intakes of flavonoids and flavonoid sub-classes were estimated using the NCI method. Hazard ratios and 95% confidence intervals were estimated using Cox proportional hazards regression modeling. Results: In this nationally representative sample of adults, from a 1988-1994 constructed cohort and followed passively for over 20 years, significant inverse associations between total flavonoids or sub-classes and CVD outcomes or diabetes were not evident. However, there was a marginal association between flavanones and CVD mortality, for males only (HR =0.93, 95 % CI 0.87, 1.00, p-value<0.04). Conclusions: In this population-based sample of individuals, associations between intakes of flavonoid and CVD mortality (with the exception of flavanone intake for men only), CVD morbidity or diabetes were not evident after 20 years of follow-up. This may be due to their low levels of usual intake, to errors in measurement of flavonoid intake, or misclassification over time of flavonoid intakes, or relatively small sample sizes.Item Effect of the kashering process on the safety and quality of meat(2019) Sherman-Wood, Robert Michael; Tikekar, Rohan V; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The process of making meat kosher, or “kashering,” involves soaking the meat, covering it in salt for at least one hour, and several rinses after. This study evaluates the effect this process has on the survivability and thermal resistance of Escherichia coli O157:H7 and Salmonella enterica serovar Newport on fresh chicken and beef, as well as the effect on quality and acceptability of both meats. The process yielded a minor reduction of both pathogens at ~1 log CFU/g. Surviving Salmonella from kashered chicken displayed an increase in thermal resistance (p<0.05). A sensory analysis panel rated salted chicken and beef higher quality and saltier than not kosher meat (p<0.05). The kashering process did change the color of both meats (p<0.05), attributable to the significant increase in salt content of the meats (p<0.05), but did not affect the texture of the meat (p>0.05).Item Relative impacts of determinants of childhood stunting in Malawi(2019) Kaur, Jasbir; Mehta, Mira; Desai, Sonalde B; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Background: High rates of stunting have persisted in Malawi for several decades. There is a need to better understand trends and determinants of childhood stunting in the population to inform effective policies and programmatic interventions. Objective: To analyze levels, trends, and distribution of stunting in a nationally-representative population of Malawian children under age five, and to analyze determinants and micronutrient levels associated with stunting in a subset of children under age two. Design: The study analyzes data from the Malawi Demographic and Health Surveys in 2000, 2004, 2010 and 2015–16 and the Malawi Micronutrient Survey in 2015–16. Stunting in children is defined as height-for-age index more than two standard deviations below the reference medium. Bivariate and multivariate analyses are used to estimate the change in stunting by socio-demographic variables, and impact of environmental enteropathy, water sanitation and hygiene, access to food, infant and young child feeding practices, women’s empowerment, domestic violence, and biomarkers of nutrition, specifically iron- deficiency anemia and vitamin A deficiency controlled for inflammation in children ages 0–59 months, adjusted for sampling design effects. Setting: Malawi is a landlocked country, divided into three regions: the northern, central, and southern regions. Subjects: Children ages 0–59 months with data on anthropometric measurements from the MDHS survey in 2000 (n=9,188), 2004 (n=8,090), 2010 (n=4,586), and 2016 (n=5,149), and from the MNS survey in 2015¬–16 (n=2,018). Results: The prevalence of stunting decreased in children from 54.3 percent in 2000 to 36.6 percent in 2016. Child’s household structure (a finished roof), child’s age, gender, birth order and birth interval, household wealth, land ownership, mother’s education, mother’s stature and BMI, and mother’s age appear to be the strongest determinants of childhood stunting. With addition of biomarkers of nutrition, inflammation, and inherited disorders, age of the child, birth order, and mother’s report of child’s size at birth and household hunger are major determinants of childhood stunting. At the cellular level, serum ferritin, retinol binding protein, and sickle cell disease and alpha-thalassemia are strongly associated with stunting in children.Item Novel Antimicrobial Treatments Based on the Interaction of Gallic Acid and UV Light: Characterization, Investigation of Antimicrobial Mechanism, and Application on Fresh Produce(2018) Wang, Qingyang; Tikekar, Rohan V; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Produce safety continues to be a challenge because produce undergoes minimal processing prior to consumption and existing sanitizers are not effective in inactivating pathogens. Novel decontamination technologies for produce are required as alternatives to traditional methods. In this project, two non-thermal process techniques were developed based on the interaction of UV light and gallic acid (GA) to enhance the safety of fresh produce. The first technique is the simultaneous application of UV-A light and GA (UVA+GA). UVA+GA treatment was effective against E. coli O157:H7, and the mechanism behind the synergistic antimicrobial effect was associated with the cellular uptake of GA, generation of reactive oxidative species (ROS), inactivation of enzymes superoxide dismutase, and damage to the bacterial membrane. In the second technique, the antimicrobial activity of GA was enhanced by its prior UV-C exposure (UVC-GA) against E. coli O157:H7 and was persistent for at least 4 weeks. The antimicrobial activity was affected by solution pH and the wavelength of UV-C exposure. The generation of ROS during UV light exposure and photo-oxidized compounds of GA such as quinone contributed to the antimicrobial activity of the UVC-GA solution. Both UVA+GA and UVC-GA treatments can enhance the inactivation of inoculated E. coli O157:H7 on produce such as spinach leaves and tomatoes without affecting the color and firmness. Common environmental stresses could confer complex cross-stress response in E. coli O157:H7 towards UVA+GA and UVC-GA treatments in that both resistance and sensitization can be induced depending on the stress applied and the technology studied. Repeated exposure to moderate UVA+GA or UVC-GA treatment can also select for sub-population that demonstrates higher resistance towards these treatments as well as cross-resistance to other lethal stress such as heat and acid. ROS scavenging enzymes and alternative sigma factor RpoS are highly likely to be associated with the adaptive response process. In conclusion, both UVA+GA and UVC-GA treatments are promising novel non-thermal techniques that are potential alternative methods for fresh produce disinfection. For future work, a better understanding of the inactivation mechanisms, optimizing of processing parameters, and the development of adaptive response associated with the two treatments need to be explored.