Theses and Dissertations from UMD
Permanent URI for this communityhttp://hdl.handle.net/1903/2
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
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item Three Clostridium species with Health Imparting Properties: In vitro Screening for Probiotic Potential(2024) Mochama, Victor Moronge; Obanda, Diana; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This research aimed to unlock the probiotic potential of the genus Clostridium, which is often overshadowed by the predominant focus on pathogenic species. The study specifically targeted three promising Clostridium species: C. disporicum, C. celatum, and C. vincentii, which have shown potential in mitigating diet-induced obesity. Despite the challenges presented by the anaerobic growth requirements of Clostridium bacteria, the study capitalized on their capacity to sporulate. This characteristic provides an avenue to use them as probiotics, with resilient and dormant spores capable of surviving food processing and harsh stomach conditions. The resilience of these spores was examined by exposing them to oxygen, heat, gastrointestinal juices, and bile salts. The spores survived oxygen exposure, exhibited resilience to both bile salts and gastric acids, and demonstrated a survival temperature of 70°C. When exposed to suitable germination conditions in vitro, the spores successfully germinated. The study assessed the colonization potential of the bacteria by evaluating their adhesion ability, and all bacteria were found to have the adhesion ability. Furthermore, a safety assessment was conducted by examining hemolytic activity and antibiotic susceptibility to selected antibiotics. The bacteria were found to be susceptible to the antibiotics and did not exhibit hemolytic activity. Bile salt hydrolase (BSH) activity and antibacterial activities were also assessed, and none of the bacteria exhibited BSH activity or antibacterial activity. Antioxidant tests revealed that C. vincentii had the highest antioxidant properties. Assessment of anti-inflammatory properties showed that C. celatum downregulated the gene expression of cytokine inflammation markers IL-6, IL-1, and iNOS while upregulating TGF-β expression. In summary all 3 bacterial species showed good probiotic potential from the in vitro tests. Particularly the formation of resistant spores that later germinated to vegetative cells that produced molecular patterns with antioxidant and anti-inflammatory properties. This necessitates further studies on their probiotic properties.Item FERMENTING KALE VEGETABLE (Brassica oleracea Var Sabella) IMPROVES ITS PROPERTIES AS A FUNCTIONAL FOOD(2023) Subedi, Ujjwol; Obanda, Diana; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The properties of kale as a functional food are well known. Fermentation is a process that has been shown to improve the health impacts of foods. In this study, we sought to determine how fermentation further improves or augments the functional food properties of kale. We tested six different fermentation methods which included traditional practices and inoculation with different bacterial species and compared outcomes to the unfermented control. After 16 days of fermentation, we quantified (i) selected bioactive components and (ii) anti-nutritional factors. We then determined (i) the antioxidant capacity of the whole vegetable, (ii) the microbiota composition of the vegetable, and (iii) the anti-inflammation capacity of the ethanolic extract of the vegetable. Fermentation significantly increased (i) the quantities of total polyphenols from 8.54 to 10.71 mg GAE/g (ii) sulforaphane from 960.8 ± 41.76 to 1777 ± 45.95 μg/g, and (iii) antioxidant capacity from 61.99 to 67.37 % respectively, and antinutritional factors oxalate and tannin content significantly reduced by 49 % and 29.83 % respectively. Fermented kale extract exhibited potent anti-inflammatory effects in macrophages by reducing the iNOS expression by 84.3% and TNF-α, IL-1β, and IL-6 mRNA levels by 62, 68, and 85.5 %, respectively. Fermenting kale changed the surface microbiota by reducing the population of the inflammation-inducing Proteobacteria while increasing health-promoting Firmicutes; including Lactobacillus. All fermentation methods had a beneficial impact compared to the unfermented control, but the mixed culture of L. lactis and L. acidophilus was the most effective. In summary, fermenting enhanced the health benefits of kale by increasing the concentration of total polyphenol, sulforaphane content, antioxidant capacity, anti-inflammation capacity, and reducing the quantity of anti-nutritional factors. Furthermore, it promoted the prebiotic and/or probiotic vehicle properties of the vegetable by changing the proportion of beneficial bacteria and those associated with inflammation.