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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.
211

Production And Processing of a Functional Yogurt Fortified With Microencapsulated Omega-3 and Vitamin E

Estrada Andino, Jose Daniel 30 June 2011 (has links)
Market and nutritional values of fermented milks can be enhanced by adding microencapsulated polyunsaturated fish oil and vitamin E. Polyunsaturated fatty acids (PUFAs) lower the risk of heart disease and vitamin E is an important lipophilic antioxidant that protects cell membranes from oxidation. This study aimed to develop functional yogurts YMSO and YMMO fortified with á-tocopherol and microencapsulated salmon oil (MSO) or microencapsulated menhaden oil (MMO), respectively and to evaluate their physicochemical properties during 1-mo of storage. Stable emulsions were prepared with 7% red salmon oil (SO) or menhaden oil (MO), 22% arabic gum, 11% maltodextrin, 0.83% á-tocopherol and 59.17% water. The emulsions were spray dried and MSO or MMO were produced. Plain yogurt (PY) was produced and 2% of MSO or MMO were added to three batches of yogurt to produce YMSO or YMMO. PY and yogurt with 22% arabic gum and 11% maltodextrin (YPAM) were used as controls. Yogurts were analyzed for syneresis, pH, color, lactic acid bacteria (LAB), thiobarbituric acid (TBA) value, fatty acid methyl esters composition, á-tocopherol content, rheological properties and microstructure. Triplicate experiments were conducted and data was analyzed at á=0.05. After 1-mo storage, the yogurts pH decreased and syneresis slightly increased regardless of the treatment and all yogurts had a similar reduction in LAB counts from 8 Log CFU/g to 6 Log CFU/g. á-Tocopherol contents of YMMO and YMSO were significantly (P<0.05) higher than those of PY and YPAM during the 4 week storage study. Initial PY, YPAM, YMMO and YMSO á-tocopherol contents were 37.65 ± 3.17, 43.03 ± 0.71, 75.61 ± 0.98, and 72.09 ± 0.18 µg/g yogurt, respectively. All yogurts had low TBA values and YMMO and YMSO had significantly higher (P<0.05) total ù-3 content than the controls. All yogurts were described as pseudoplastic fluids and showed viscoelastic characteristics during 1 month storage. The study demonstrated that PY can be fortified with fish oil and á-tocopherol.
212

Comparison of Thermally Pasteurized and Ultrasonically Pasteurized Blueberry Juice (Vaccinium corymbosum) and an Investigation of Blueberry Juice Effect on Lipid Oxidation During Microencapsulation of Polyunsaturated Fish Oils

Mohideen, Fathima Waheeda 07 July 2011 (has links)
Blueberries have received considerable attention due to their content of health promoting compounds such as polyphenols and anthocyanins. Thermal pasteurization (TP) is known to cause degradation of anthocyanins and juice color. Microencapsulation, particularly with incorporation of blueberry antioxidants, can improve the stability of menhaden (MO) and salmon (SO) fish oils rich in omega-3 fatty acids. The objectives of this research were to study the effect of TP and continuous ultrasonication processing on the microbiological, chemical and physical properties of blueberry juice (BJ) and to determine the effect of BJ on MO and SO lipid oxidation during microencapsulation. Fresh blueberries were blanched, blended and then centrifuged to obtain the juice. BJ samples were pasteurized at 80, 85 and at 90°C for 1, 2, 3, 4 and for 5 min. Unpasteurized BJ was pumped at 24 mL/min and at 93.5 mL/min to the continuous flow cell of an ultrasonic processor, where it was sonicated at three treatment levels (40, 80 and 100% amplitude). Sonicated (non-TP) and unsonicated (TP) juices were analyzed for coliforms, total aerobes, yeasts and molds. Total anthocyanin content, total phenol content, antioxidant activity, ◦Brix, titratable acidity, pH and color were also determined for both sonicated and unsonicated juices. Emulsions prepared with each type of fish oil having 0, 5 and 10% BJ were separately spray dried and microencapsulated powders were produced. All the powders were evaluated for microencapsulation efficiency (ME), color, peroxide value, anisidine value, and fatty acid methyl ester profile. Sonication at higher intensities reduced microbial counts equivalent to TP. Sonication did not affect BJ color or anthocyanins content while TP showed reduction of anthocyanins and change in juice color with increased temperature and time. Furthermore TP juices showed signs of Maillard browning with increased temperature and time. All microencapsulated MO and SO powders had high ME with low surface oil content. All powders containing 10% BJ showed less lipid oxidation during emulsification and spray drying than powders containing 5% BJ and 0% BJ. This study demonstrated that ultrasonication can be an alternative pasteurization treatment to TP and that BJ reduced lipid oxidation in fish oils during microencapsulation.
213

Changes in Select Phenolic Compounds During Ethanol Fermentation and Acetification of Raspberry, Blueberry and Persimmon

Tan, Yen-Ping 07 July 2011 (has links)
Polyphenols are major dietary components in fruits and vegetables. Many research and epidemiological studies have reported that phenolic compounds, such as anthocyanins, may have a protective effect against various degenerative diseases. Phenolics in grape wine have been extensively studied but information on changes of phenolics in wine and vinegar made from other fruit crops is limited, however. This research started with the objective of determining the effect of proteases in preventing phenolic and, specifically, anthocyanin degradation in the ethanolic fermentation of black raspberries to reduce sugar content. The results of this study led to investigations of changes of other polyphenols in persimmons and blueberries during both ethanolic (vinification) and vinegar (acetification) fermentations. Initial results showed that a 1% neutral bacterial protease could retain anthocyanin in open vinification of black raspberries but the protease treatment provided no benefit when a closed fermentation was used. Additional research using closed vinification followed by acetification of persimmons indicated that phenolics were significantly affected by these fermentations. Phenolics in astringent persimmons were significantly degraded during both vinification and acetification while phenolics in non-astringent persimmons actually increased during vinification but decreased during acetification. In blueberries, anthocyanin and epicatechin were increased during vinification but decreased during acetification. The lipid-protective properties of fruit wine and vinegar was also investigated. In this study of antioxidant properties, blueberry vinegar was more effective than blueberry juice or blueberry wine in preventing EPA and DHA degradation in salmon oil-in-water emulsion model system. This thesis research provides informative insights concerning changes in polyphenols, such as anthocyanin, during vinification and acetification of some fruit crops. The information is especially beneficial to the juice, wine and vinegar industries since polyphenols are one of the major health promoting constituents in fruit juices, wines and vinegars.
214

Production of Spray-Dried Honey Powder and its Application in Bread

Kosal Ram, Ahalya 06 July 2011 (has links)
Honey is a natural sweetener with various beneficial properties including anti-oxidant and anti-microbial activity. Retrograded starch is known to have hypocholesterolemic effects and act to inhibit fat accumulation. Honey powder produced using retrograded starch can be used as an alternative to sucrose in many bakery products like bread. The objectives of this study were to produce a honey powder containing retrograded starch, characterize the powder and use it as an alternative to sucrose in bread formulations. The honey powder was produced by spray drying honey using retrograded starch as a drying agent. The spray dried honey powder was characterized for moisture and sugar contents and color. Three bread formulations were prepared with (1) 100% liquid honey (HNY), (2) 50% substitution of sugar with honey powder (SHP) and (3) 100% honey powder (HP). A bread formulation prepared with only sugar was used as a control (S). Breads produced from all four formulations were analyzed for loaf volume, weight loss, density, specific volume, moisture content, texture, and freezable water. Triplicate experiments were conducted and data were statistically analyzed at á = 0.05. The dried honey powders contained glucose between 10.39±0.35 and 11.58±0.29 g/100g, fructose 12.07±0.49 and 15.14±0.29g/100g, sucrose 0.05±0.01 and 0.21±0.13g/100g and maltose 0.60±0.08 and 1.27±0.62g/100g. Among the bread samples HP showed highest loaf volume (mL) at 1462±45 while SHP, HNY and control showed decreasing loaf volumes at 1303±199, 1155±91 and 1100±66, respectively. All bread samples showed an increase in firmness and HP had a lower rate of staling than the other bread samples during storage. Control bread samples contained more freezable water (g/g solid) at 0.21±0.003 than HNY, SHP, and HP which had 0.20±0.003, 0.19±0.01 and 0.13±0.01, respectively. The study demonstrated that spray dried honey powder with retrograded starch could be used as a substitute for sucrose in baking bread.
215

Inhibitory Effects of Berry Anthocyanins on Palmitic Acid- or Lipopolysaccharide-Induced Inflammation in Human Preadipocytes

Gao, Chenfei 07 July 2011 (has links)
Obesity is an inflammatory disease associated with the development and progression of chronic degenerative diseases including insulin resistance, cardiovascular disease (CVD), type 2 diabetes mellitus (T2DM), and cancer. Circulating free fatty acid (FFA) are known risk factors promoting inflammation that can lead to CVD. Pre/adipocytes are known storage of low grade inflammatory biomarkers associated with obesity. However, the effects of dietary anthocyanins on inflammatory biomarkers in preadipocytes have not been reported. Berries are rich sources of naturally occurring antioxidant polyphenolics. There is increasing interest in the ability of berry anthocyanins to provide health benefits against obesity. Anthocyanins were isolated from blueberry, blackberry, cranberry and black currant and analyzed by spectrophotometry and liquid chromatography. The objective of this study was to test the effect of berry anthocyanins on palmitic acid (PA)-induced inflammatory biomarkers in human preadipocytes. Comparison was made with the effect of berry anthocyanins on lipopolysaccharide (LPS)-induced inflammation in similar human preadipocytes. Preadipocytes from obese women were incubated with different concentrations (10-40ìM) of berry anthocyanins for 24 h followed by addition of 100 ìM PA and additional incubation for 24h or 100ng/ml of LPS for 8 h. In another treatment, preadipocytes were incubated with 100 ìM PA for 24h or 100ng/ml of LPS for 8 h and then incubated with 10-40ìM anthocyanins for 24h. All incubations were performed at 37 °C in a 5% CO2 humidified incubator. Pro-inflammatory cytokines IL-6, IL-8 and MCP-1 were analyzed in conditioned preadipocyte media by ELISA. NF-êB and COX-2 from preadipocyte lysates were analyzed by Western Blot. PA or LPS induced up-regulation of the pro-inflammatory biomarkers. Berry anthocyanins significantly inhibited PA- or LPS-induced inflammation when anthocyanins were added to the preadipocytes prior to PA or LPS addition. However, the same anthocyanins were weak inhibitors of PA- or LPS-induced inflammation when preadipocytes were first incubated with LPS or PA. The results of our investigation show that berry anthocyanins may be effective in preventing PA- or LPS-induced low-grade inflammation in preadipocytes.
216

Inhibitory Activity of Ginger Oil Against Breast Cancer Cells

Karki, Namrata 08 July 2011 (has links)
Breast cancer is the leading cause of cancer related mortality in women. The estimated new cases and death for 2010 in the US for females were 207,090 and 39,840 and for men were 1,970 and 390 respectively. Breast cancer cells contain cancer stem cells (CSCs), which represent less than 5% of the total cancer cell population, but accounts for continuous proliferation and growth. Breast cancer is highly metastatic and can spread to various parts of the body. Signaling through cell surface markers, including CD44/CD24/ALDH1 in breast cancer, pro-survival factors, including Hsp90 and other client proteins, angiogenic biomarkers and telomerase activity are essential for cancer cell renewal and could represent putative targets for inhibiting breast cancer cell development. The aim of this research was to determine the in vitro anti-carcinogenic property of ginger oil against breast cancer cells (MDA-MB-231). We investigated the inhibitory activity of ginger oil against the biomarkers that are essential for breast cancer cell viability or proliferation. Cells were incubated with vehicle (DMSO), or ginger oil at concentrations, 0.05% to 0.2% of the volume of the media for 72 h at 37 °C and 5% CO2. Ginger oil dose-dependently inhibited the viability and proliferation of breast cancer cells in vitro. The mechanism of breast cancer cell inhibition included induction of caspase-mediated apoptosis, cell cycle arrest, inhibition of Hsp90 and some of its client proteins, down-regulation of cell surface biomarkers, CD44/ALDH1 in breast cancer cells, inhibition of the biomarkers of angiogenesis, and down-regulation of the activity of telomerase.
217

In Vitro Inhibitory Activity of Black Seed Oil and Potassium Chloride against the Biomarkers of Triple Negative Breast Cancer

Jombai, Tamaratina 11 July 2011 (has links)
Breast cancer is the leading cause of death among women and is highly heterogeneous in nature. One very aggressive subtype of this disease is Triple Negative Breast Cancer. Triple Negative Breast Cancer (TNBC), is a very aggressive disease characterized by the lack of expression of estrogen receptors (ER), progesterone receptors (PR) and human epidermal growth factor receptor-2 (HER-2). TNBC patients account for approximately 15% of total breast cancer patients. This breast cancer subtype is characterized by high mortality rate, and is typically associated with poor prognosis. Current clinical methods have proven to have low success rates against TNBC, it is proposed that prevention by dietary approach with naturally occurring compounds in foods will be more effective. The objective of this research was to study the inhibitory activity of black seed oil and potassium chloride against the biomarkers of triple negative breast cancer. Hormone-independent MDA-MB-231 breast cancer cells were incubated with black seed oil, potassium chloride, or the combination of black seed oil with potassium chloride and incubated at 37 ºC and 5% CO2 in a humidified incubator for 24, 48, or 72 h. Cell viability was measured by MTS assay. The effect of black seed oil on angiogenesis was determined using in vitro angiogenesis tube formation assay. Cancer cell cycle was analyzed by flow cytometry. The expression levels of biomarkers of TNBC cells were evaluated by Western blots. This study showed that black seed oil and potassium chloride proved efficient in down-regulating TNBC associated biomarkers including ALDH1, CD44, ESA, PI3K/Akt, Erk, COX-2, NFκB, Hsp90, p53, p21, Bax, and Bcl-2. The results indicate that black seed oil or KCl or their combination can attenuate the biomarkers of triple negative breast cancer MDA-MB-231, suggesting a potential preventive role against the disease.
218

Identification of Algal Strains by PCR Amplification and Evaluation of Their Fatty Acid Profiles for Biodiesel Production

Moreno, Reynaldo 24 January 2012 (has links)
Four microalgae, obtained from different brackish and fresh water sources within the state of Louisianas Southeast region, were evaluated for their potential use in the production of biodiesel. The microorganisms were isolated and identified using genomic DNA, and 16S rRNA or 18S rRNA gene amplification followed by sequencing. The resultant sequences were compared with those available on the NCBI website database through the BLAST bioinformatic tool. The results showed high correlation with known nucleotide sequence identities at 99 % with Synechococcus sp., 98 % with Sellaphora pupula, 99 % with Chlorella sorokiniana, 99 % with Scenedesmus abundans, and 99 % with Chlorella vulgaris (control). The fatty acid profiles of the identified organisms grown using 5 % CO2 aeration into the growth media were evaluated and were found to be different to the control group (0.037 % CO2). In Synechococcus sp., total fatty acids (TFA) decreased from 20.63 g kg-1 to 17.62 g kg-1 dry biomass with the appearance of C18:2 and C18:3, which were absent in the control. TFA from Sellaphora pupula decreased from 54.8 g kg-1 to 24.4 g kg-1 dry biomass and contained the greatest C16:1. The extracted TFA from Scenedesmus abundans increased from 14.14 g kg-1 to 31.63 g kg-1 and displayed the highest content of C18:1. For Chlorella vulgaris UTEX 259, TFA content increased from 15.14 g kg-1 to 47.83 g kg-1, and 50 % of that total was C18:3. The TFA content from Chlorella sorokiniana decreased from 29.82 g kg-1 to 23.99 g kg-1; however, it had a lower C18:3 which allowed for a balanced fatty acid profile in terms of cetane number, oxidative stability, viscosity and low temperature conditions. The aforementioned conditions, plus owning the best biomass productivity when using 5 % CO2, deemed Chlorella sorokiniana as the best candidate of the strains evaluated for the production of biodiesel.
219

Consumer and Processor Methods to Control Salmonella and Listeria in Shrimp

Edwards, Genevieve Anne 03 January 2012 (has links)
A common method used by consumers to determine if shrimp are thoroughly cooked when boiling, is to wait until the shrimp float to the top of the water and are pink in color. The purpose of this study was to determine whether the current floating and color cooking method is adequate to ensure the elimination of Listeria and Salmonella species. Furthermore, to determine if processing and storage methods reduce the effectiveness of this method. Shrimp samples were submerged into bacterial suspensions for 30 min then allowed to air dry for 1 hr and color parameters were measured using a colorimeter. Shrimp samples were separated into three groups; day 0, 1, or 2, and stored at 4ºC. The shrimp samples were then treated by placing into boiling water (100°C) on days 0 (inoculation day), 1 and 2. The shrimp were immediately removed from the boiling water once they started floating and color parameters were measured. Bacterial counts were determined by making serial dilutions, spread plating, incubating plates at 37°C for 24 h and calculating Log CFU/g. Typical storage conditions, the use of the additive sodium tripolyphosphate and freezing methods were then tested for their effect on the control of these pathogens in boiled shrimp. Initial bacterial counts ranged from 3.0 to 5.4 Log CFU/g of shrimp. On day 0, 1, and 2 all bacterial counts were reduced to non-detectable levels for shrimp samples that floated in the boiling water. The bacterial counts remained at non-detectable levels during refrigerated (4°C) storage. The redness (a*), yellowness (b*) and lightness (L*) were significantly higher (p<0.0001) in the cooked shrimp compared to uncooked for all days tested. However, the standard deviation for the redness (a*) in the cooked shrimp was large indicating a wide range of pink coloration for all days tested. The flash freezing method led to development of heat resistance in Listeria monocytogenes. Brine freezing was determined to be a better method for microbial reduction. Our results suggest that boiling shrimp until they float will significantly reduce Listeria species and Salmonella species but color change will not and color variation can occur.
220

Commercial Household Disinfectant Inactivation of Bacillus cereus Spores on Fruit and Vegetable Surfaces

Kerr, Helen 01 August 2009 (has links)
Studies were conducted to test the efficacy of several common household products containing antimicrobial compounds for inactivating spores of Bacillus cereus, as a surrogate for B. anthracis, on fresh fruit or vegetables. Additionally, the effect of storage time on hypochlorite activity of household products was determined. Bacillus cereus ATCC 33018 and ATCC 49064 were used in a cocktail for all tests. Household disinfectant and/or cleaning products with potential for sanitization were purchased in a retail market and were selected based upon efficacy against B. cereus in previous tests in milk. The active components were NaOCl, HCl or H2O2. For produce, cantaloupe melons and spinach were obtained from a local retail market and rinsed with sterile deionized (DI) water. Cantaloupe rinds were removed, trimmed to remove the mesocarp, cut into 25 cm2 sections and placed in sterile Petri dishes. Sections of melon and spinach leaves were spot inoculated with 0.1 ml of B. cereus and allowed to dry for 30 min at 25oC. Sanitizing products were sprayed onto the surface of the produce and the produce was allowed to stand for various times. Produce was then placed in neutralizer buffer to arrest the activity of sanitizing compounds and survivors were enumerated on non-selective media. To determine the effect of product age on activity, three commercial NaOCl-containing products that were past, at and 6 mo from the expiration dates were evaluated. Spinach and cantaloupe were tested as described previously. For the cantaloupe melon rind the control population mean was 7.15 + 0.07 log CFU/cm2. The log reduction was > 5.15 for undiluted NaOCl (Clorox®, 6.00% NaOCl) and inactivation took 120 min though the greatest reduction was observed in the first 10 min. For products containing 1.84%-2.40% NaOCl, log reductions were 2.75 to 3.40 over 180 min. For spinach, the control population mean was 7.37 + 0.01 log CFU/leaf. A > 5.84 log reduction in B. cereus spores was found for both undiluted NaOCl (Clorox®) and HCl (The Works Drain Opener, 20.00% HCl). However, the former reduced the viable spore population to the lowest detection level in 10 to 60 min while the latter took approximately 3 h. A 4.23-4.60 log reduction occurred with the 1.84%-2.40% NaOCl-containing products after 180 min. Hydrogen peroxide had the least effective sporicidal capabilities of the solutions tested reducing the population by less than 1 log. With respect to effect of storage on sporicidal activity of HOCl-containing products, samples stored up to 1 year past expiration were compared with those stored for 6 months prior to expiration and purchased fresh. There was no significant difference in the in vitro inactivation of B. cereus spores among the products. B. cereus spores were inactivated to below detectable levels after 1 min in 50% and 25% commercial strength solutions (>4.0 log CFU/ml). These findings were confirmed utilizing cantaloupe rind and spinach leaves treated with HOCl-containing products of the same storage times. B. cereus spores were inactivated to below the level of detection (>5.84 log CFU/cm2, >5.15 log CFU/cm2) in 10 min and 60 min for spinach and cantaloupe respectively, regardless of compound age.

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