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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Extractable And Non-Extractable Polyphenols From Mango

Ma, Yuchao 21 March 2018 (has links) (PDF)
Polyphenol from fruits and vegetables have been proved that can lower the risk of many chronic disease. However, most studies are only focus on the extractable polyphenols right now. Non-extractable polyphenols may also have many important biological effects. The objective of this study was to find the difference between the extractable polyphenol and non-extractable by alkaline hydrolysis, acid hydrolysis and enzyme hydrolysis, compare the total phenolic content, flavonoid content and tannin content, and study their anti-inflammation effect, anti-cancer effect and antioxidant effect. The results showed that NEP alkaline hydrolysis was the best way to extract mango polyphenol. It had the highest total phenolic content and tannin content. The ORAC data also showed NEP alkaline hydrolysis had the best antioxidant effect. NEP alkaline also showed the dose-dependent inhibition manner. The extractable polyphenol showed better anti-inflammation effect then non-extractable polyphenol. Overall, we can conclude the secondary extraction did in fact yield more polyphenol from residue and non-extractable polyphenol have very similar effects as the extractable polyphenol.
2

Development of Nanoemulsion-based Delivery Systems for Evaluation of Triglycerides Bioactivity in Caernohabditis Elegans

Colmenares, Jose D 23 November 2015 (has links)
Digestion and absorption of bioactive free fatty acids have been studied using the nematode Caernohabditis elegans (C. elegans). However, fatty acids mostly occur in foods in the form of triglycerides, which are highly hydrophobic molecules with low water-solubility, thereby making it difficult to study the fate of ingested fatty acids in C. elegans. The purpose of this research was to develop a method to deliver hydrophobic bioactives, including triglycerides, into C. elegans. Nanoemulsions containing triglyceride nanoparticles were prepared by sonication, and nanoparticle ingestion was confirmed by optical and confocal microscopy, and quantified by spectrometry. Changes in fatty acid composition were measured to confirm the absorption of triglycerides delivered as nanoparticles. Nanoparticles with a wide range of particle diameters (40 to 500 nm) were ingested by C. elegans. The ingested triglyceride amount was dependent on the size and concentration of the nanoparticles, but the fatty acid composition of C. elegans was not significantly changed by dietary triglycerides. Nanoemulsion based-delivery systems enable C. elegans to be used for evaluation of hydrophobic bioactives and may provide a useful tool for testing their biological activities.
3

Effect of frying oil consumption on colon tumorigenesis in mice

Yang, Ran 20 August 2019 (has links)
Deep-frying is now a popular cooking method all over the world due to its low cost and time-saving property. It also provides special and likeable flavor, helps prolong shelf lives of commercial products, and offering food products of stable quality. However, by- products formed during the frying process, such as malonaldehyde, were shown to be harmful to human health. Such compounds can be taken in when having fried foods, potentially inducing or promoting some diseases. However, there is limited research studying the direct effects of frying oil consumption on cancer. In order to have a better understanding of the effects on cancer by frying oil, we used a well-established AOM/DSS- induced colon cancer animal model to study the impact by frying oil. After 10-week treatment with diet containing deep-frying oil (3.8% in diet) or with un-oxidized oil (10% in diet), the mice showed enhanced tumorigenesis in colon, where the total tumor burden significantly increased (4.5 ± 1.9 mm2 for the treatment group, compared with 0.5 ± 0.5 mm2 for the control group, P < 0.05). Also, the expression of pro-inflammatory and pro- tumorigenic cytokines (Mcp-1, Inf-γ, Il-6, Il-1β, Myc, Axin2 and Vegf) were increased in the mice treated with frying oil diets. Together the results showed that consumption of deep-frying oil promoted the colorectal cancer in mice, providing more detailed information for health instruction.
4

The Effects of Roasting Time and Temperature on the Antioxidant Capacity of Cocoa Beans from Dominican Republic, Ecuador, Haiti, Indonesia, and Ivory Coast

Harrington, Whitney Leigh 01 August 2011 (has links)
Roasting is an important processing step for developing cocoa flavor, color, and aroma. Cocoa beans contain polyphenolic compounds, which can be desirable antioxidants. Oxygen Radical Absorbance Capacity (ORAC) values can be used as an indicator of health benefits of antioxidants in foods. ORAC values measure total antioxidant capacity of different foods by measuring antioxidant scavenging activity against peroxyl radical induced by 2,2’-azobis (2-amidinopropane) dihydrochloride (AAPH). This measurement of total antioxidant capacity gives a complete assessment during which the inhibition time and inhibition degree are measured as the reaction comes to a completion. ORAC values were determined as Trolox Equivalents (TE). Cocoa beans were also measured for antioxidants using Total Phenolics assay and DPPH assay and measured as gallic acid equivalents (GAE). Cocoa beans from the Ivory Coast were roasted at varying times (10-40 minutes) and temperatures (100ºC -190ºC). It was determined that cocoa beans from the Ivory Coast, roasted at 130ºC for 30 minutes resulted in an ORAC value of 522,789 μmol (micromoles) TE/g, GAE value of 2.46 mg/L as determined by Total Phenolics, and GAE value of 1.48 mg/L as determined by DPPH assay. The analyzed values tended to decrease at the highest temperatures and times of roasting. Cocoa beans from different countries were roasted at 130ºC for 30 minutes and antioxidants were analyzed. It was determined that Dominican Republic and Ecuador had the highest TE values (487,913 and 463958 μmol (micromoles) TE/g respectively). GAE differed and Total Phenolic assay found Haiti had the highest GAE (3.26 mg/L) and DPPH assay found Ivory Coast and Dominican Republic had the highest (0.623 and 0.610 mg/L respectively). If an acceptable flavor, color, and aroma of cocoa can be developed at a roasting temperature closer to 130ºC than to 160ºC, then a greater antioxidant content should occur in dry cocoa powder.
5

Click Chemistry Approach to Analyze Curcumin-Protein Interactions in vitro and in vivo

Zhou, Jingyi 20 August 2019 (has links)
Over the past decades, numerous studies shown curcumin, a dietary compound derived from turmeric, has a variety of health-promoting actions, such as anti-oxidant, anti-microbial, anti-inflammatory, and anti-cancer effects, making curcumin the most promising dietary compound for disease prevention. However, the underlying mechanisms by which curcumin has these health-promoting effects are not well understood. A better understanding of the molecular mechanism of curcumin could help to develop novel strategies to reduce the risks of some human diseases. Protein thiols play important roles in cell signaling, and recent studies showed that curcumin could covalently react with protein thiols, supporting that curcumin-protein interactions could contribute to the health-promoting effects of curcumin. However, the curcumin-protein interactions are under-studied. Notably, it remains unknown whether oral intake of curcumin could covalently interact with protein in vivo. In this project, we synthesized a click chemistry probe of curcumin (Di-Cur), and used this probe to characterize curcumin-protein interactions both in vitro and in vivo using a click chemistry-based imaging approach. Our results demonstrate that orally administrated curcumin could form curcumin-protein adducts in specific tissues of the mice, which may contribute to the potent biological effects and poor pharmacokinetics of curcumin.
6

Factors Affecting Sensory Acceptance of Thickened Liquids Used in Dysphagia Management

Cox, Allison N 20 October 2021 (has links) (PDF)
Between 4-16% of adults in the United States have experienced difficulty swallowing at some point during their lives. Difficulty swallowing, or clinically referred to as dysphagia, poses increased concern when drinking beverages. While no treatment is currently available, it is often recommended that liquids be thickened to improve the safety of swallowing and prevent liquids from being aspirated in the lungs. However, thickened liquids are poorly accepted by individuals with dysphagia. Taste and flavor suppression has been shown in various thickened liquid matrices, but the mechanisms for understanding these changes in perception are quite complex. Additionally, literature focused on dysphagic patients’ experiences with different types of beverages and clinicians’ experiences with thickening beverages is minimal. The study had two main goals: 1) explore how sensory properties including texture, taste, and flavor affect acceptance of specific thickened liquids and 2) determine challenges clinicians experience with thickening different beverages. This was achieved through a quantitative and qualitative online survey administered to clinicians (n=83; 96% speech-language pathologist) in the United States who work with dysphagia patients. Free-response questions related to thickening issues highlighted challenges with carbonation, temperature, and dairy products. Coffee, water, soda, milk, and oral nutritional supplements were the most complained about thickened beverages, respectively. Disliking of texture was a common complaint for each beverage likely due to the dissimilarity to the unthickened version and challenges associated with thickening. Off-flavors were reported for each beverage and were the most present in water. Additionally, clinicians noted the thickened version of the beverage typically has less flavor. To increase the acceptance of thickened liquids, clinicians believe the texture and flavor need significant improvements. Interdisciplinary work in the field of food science is needed to create a smoother consistency, more stable thickness across time and temperature, and improved flavor/taste to develop more enjoyable beverages for dysphagic patients.
7

Fat Lowering Effects of Fisetin in Caenorhabditis elegans

Rodriguez, Nikolas J 09 July 2021 (has links) (PDF)
Fisetin, a flavanol with anti-inflammatory, anti-cancer, and anti-aging properties, has shown promise for reducing fat accumulation in tissue culture and animal models. This plant sourced compound has limited studies supporting its effects on fat accumulation. Therefore, this study was completed to determine fisetin’s role in fat reduction along with its mechanism of action using Caenorhabditis elegans. C. elegans is a small roundworm with roughly 65% of its genes being conserved in humans related to disease. In this study, 100 and 200 µM fisetin has shown to reduce fat accumulation in wild-type worms. Body size, locomotion, and pumping rate were assessed in wild-type worms to determine if fisetin modified worm size, speed, and feed behavior, respectively. Mutant strains were tested to elucidate a potential pathway, of which tub-1 knockout mutants failed to reduce fat accumulation after fisetin treatment, suggesting this gene’s involvement. Gene expression of tub-1 was not altered by fisetin treatment, suggesting potential post-transcriptional regulation of fisetin. This study serves as an introduction to fisetin’s fat reducing effects via a tub-1 dependent mechanism.
8

Characterization of a sample population of dental hygiene patients with and without periodontal disease as determined through fatty acid and fruit and vegetable intake

Jackson, Caitlin R 01 May 2015 (has links)
This study was designed to compare the fatty acid and fruit and vegetable intake of people with and without periodontal disease. Periodontal disease affects approximately 15 percent of the developed world population. Participants filled out a food frequency questionnaire (FFQ) for both fruit and vegetable and fat intake. A sample of whole blood (EDTA) was collected to determine the fatty acid profile of participants’ red blood cell (RBC) membrane. This analytical procedure determines the average fatty acid intake of the participant over the previous 90 to 120 days. Participants were classified as case (n=10, patients diagnosed with periodontal disease) or control group (n=10, patients without periodontal disease). Our hypothesis was that the case group would have higher fat intake and lower fruit and vegetable intake, with lower levels of omega-3 fatty acids and higher levels of omega-6 fatty acids in the RBC membrane. FFQ results indicated that case participants consumed significantly higher amounts of total fat (109.02 vs. 94.46g/d; p= .05), saturated fat (35.102 vs. 28.242g/d; p= .033) and their diets had a higher percentage of total dietary fat (38.73% vs. 34.99%; p=.044). FFQ for fruit and vegetable intake showed no significance between the case and control groups (4.41 vs. 4.56 servings/d; p=.871). For the most part, there were no significant differences between the percent composition of the individual fatty acids isolated from the RBC membrane or in ratios of omega-3 to omega-6 fatty acid groups as determined by RBC fatty acid analysis. Results indicated a numerically lower intake of omega-3 fatty acids in the case than in the control group. Likewise, there was a numerically higher intake of omega-6 fatty acids in the case group. These numbers demonstrate a trend towards the hypothesis being correct and patients with periodontal disease consuming more omega-6 fatty acids and less omega-3 fatty acids.
9

Real-Time PCR Combined with DNA Barcoding for the Authentication of Red Snapper (Lutjanus campechanus) Fillets

Isaacs, Rachel 01 August 2019 (has links)
Seafood substitution is a worldwide problem due to factors such as limited monitoring coupled with complex supply chains. Red snapper (Lutjanus campechanus) is a highly valued and overfished species that is commonly substituted with other fish, such as tilapia, rockfish, and other snapper species. DNA barcoding is typically used by regulatory agencies to detect seafood substitution; however, it is expensive and time-consuming. A rapid, real-time PCR assay targeting red snapper was developed previously for use in fisheries management; however, it has not been tested for its ability to detect red snapper species substitution. The objective of this study was to assess the ability of the real-time PCR assay to identify red snapper fillets and differentiate red snapper from common substitute fish species in combination with DNA barcoding. A total of 21 fresh/frozen fillets labeled as “red snapper” were tested with real-time PCR, along with 57 fresh/frozen fillets representing 15 of the most common categories of fish mislabeled as red snapper. All samples were tested with DNA barcoding to confirm the identity of fish species. Real-time PCR parameters were optimized to reduce background signals associated with cross-reactivity. Overall, real-time PCR identified 4 samples as red snapper: 3 were authenticated as red snapper with DNA barcoding and 1 was identified as mahi-mahi. Overall, 40% of all samples and 91% of “red snapper” samples were considered mislabeled according to DNA barcoding. Red snapper was substituted with other snapper species (e.g., Lutjanus malabaricus, Lutjanus peru, Ocyurus chrysurus, and Rhomboplites aurorubens), rockfish (Sebastes flavidus and Sebastes brevispinis), sea bream (Pagrus major/Pagrus auratus), and mahi-mahi (Coryphaena hippurus). The real-time PCR assay tested in this study can serve as a rapid screening test for the detection of mislabeled species, which can then be confirmed with sequencing techniques. This species identification technique has the potential to be used by regulatory agencies to rapidly determine the authenticity of red snapper on-site.
10

Developing, Refining, and Validating a Survey to Measure Adolescent Food Safety Self-Efficacy

Brandon, Monica K 01 December 2010 (has links)
Self-efficacy is a proven indicator of predicting risky behaviors, but without a baseline level of adolescent food safety self-efficacy to develop targeted interventions it is difficult to produce meaningful behavior change. The research question around which this study was designed is: To what extent can a validated instrument accurately capture adolescent beliefs of food safety self-efficacy. Through rigorous field testing and statistical analysis we hypothesize a valid and reliable instrument can be created for measuring adolescents’ food safety self-efficacy. The purposes of this study included: (a) development of a high quality, food safety self-efficacy instrument, (b) validation of the instrument through expert review, and (c) field testing of the instrument to measure adolescent food safety self-efficacy. A field test of the instrument was conducted with adolescent students (n=91) using expert review and the following analyses: a) the normality, (b) the validity, and (c) the reliability. The final instrument yielded 16 items that were within the boundaries of normality, passed expert review, and/or had strong validity and reliability results. The results of this study indicate that an instrument accurately measuring and capturing adolescent food safety self-efficacy is possible to create by using proven valid and reliable methods.

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