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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.
21

The Effects of 8 Weeks of Low Dose Supplementation of Creatine and Sodium Bicarbonate on Exercise Performance

Morris, Amanda Jessica 01 December 2013 (has links) (PDF)
Short-term (3-7 days), high doses of creatine (20g/d) and/or sodium bicarbonate (0.5g/kg body weight) supplementation increase exercise performance during short term high intensity activities; however, it remains unclear whether long-term, low doses of these supplements have a positive impact on exercise performance. The purpose of this study was to determine the effects of long-term (8 weeks), low dose creatine supplementation on exercise performance, and whether combining creatine and sodium bicarbonate supplementation has an additive effect. Sixty-three healthy, habitually active, adults (28 M, 35 W; 22+2 years; 23+ 3 BMI) were randomly assigned by sex to one of three supplement groups: placebo (PL), creatine only (3g/day; Cr), or creatine plus sodium bicarbonate (3g creatine plus 1g sodium bicarbonate; Cr+Sb) for 8 weeks. Before and after supplementation subjects completed two exercise performance tests on separate days. Subjects completed repeated Wingate sprint tests (6 x 10 second sprints) and changes in the slope across the 6 sprints (rate of decline) was analyzed between groups. We also collected 5 km time-trial and the data were analyzed using repeated measures ANOVA. In the repeated sprint test, peak power output slope was significantly decreased (P=0.04) in PL (-83%) and Cr+Sb (-82%) but did not change in Cr alone and was significantly better (P=0.03) than Pl and Cr+Sb. Similarly, mean power output slope significantly decreased (P0.05) in time to completion. However, Cr alone significantly improved time to completion (-3%; P=0.01). Taken together, these data suggest that long-term, low dose creatine supplementation increases exercise performance but adding sodium bicarbonate supplementation has no beneficial impact on exercise performance.
22

Optimization of Peracetic Acid as an Antimicrobial Agent in Postharvest Processing Wash Water

Ghostlaw, Tiah 25 October 2018 (has links) (PDF)
The Food Safety Modernization Act (FSMA) has a regulation stating that there can be no detectable generic Escherichia coli in agricultural water. The objective of this study was to optimize the use of peracetic acid (PAA) as a mitigating strategy in postharvest processing. This project began by investigating the impact of storage temperatures on stability of a commercially available PAA sanitizer. Regression analysis showed a quadratic relationship in the concentration of PAA over 12 weeks when storing the product at 4, 20 and 37°C. Stability of the product was also investigated in the presence of organic load over time at 60ppm PAA. PAA significantly decreased at an organic load level of 750COD. From this, the impact of various ratios of hydrogen peroxide (H2O2) and PAA were investigated further to see the efficacy against E. coli O157:H7 over three hours with reinoculation of bacteria after 3 hours. A higher level of PAA in the solution had a greater inactivation efficacy against E. coli O157:H7. The impact of concentration, organic load, temperature and pH on the efficacy against E. coli O157:H7 and stability of PAA over four hours was then investigated. All of the conditions tested showed a significant decrease in H2O2 and PAA concentrations over time, except at concentration of 80ppm, with varying rates of depletion under each condition tested. This study will help to create guidance on optimizing the use of PAA. With this knowledge growers can understand how changes in their post-harvest processing water can affect sanitizer performance.
23

Cofermentation, Post-Alcoholic, And Post-Malolactic Fermentation Blending Of Malbec, Merlot And Petite Sirah Wines

Vega-Osorno, Armando Arturo 01 September 2022 (has links) (PDF)
A two-year study was conducted to assess the effects of cofermentation on red wine varietals. During the winemaking process, wines can be made from two or more varieties by picking, crushing and fermenting them together, a practice known as cofermentation. They can also be blended either after the completion of alcoholic fermentation or after malolactic fermentation. In the first year of the study, two grape varieties, Merlot (Mer), and Malbec (Mal) were cofermented. On the second year, a third varietal, Petite Sirah (PS) was also studied. Cofermented wines containing every possible binomial combination of the varietals was made and one trinomial on 2019. The cofermented wines were compared to monovarietal wines and also to wines that were produced by blending either after alcoholic fermentation or after malolactic fermentation. The phenolic profile of the wines was followed from the onset of fermentation up to 36 months of bottle aging for the 2018 vintage and in the case of the 2019 vintage, up until 250 days after crushing. In 2018, cofermented wines and wines that were blended after malolactic fermentation had an anthocyanin profile that was more similar to Malbec than to Merlot, while the tannin profile was more resemblant of Merlot. In 2019 cofermentation improved the anthocyanin content when compared to post alcoholic and post malolactic blend only when the three varietals were cofermented. A sensory analysis with 10 trained individuals was conducted on the 2018 vintage. It was demonstrated that Malbec wines had a higher amount of red fruit aromas while Merlot wines were perceived as being more astringent. Cofermented and post malolactic fermentation blended wines were indistinguishable to panelists and blending after alcoholic fermentation produced wines that highlighted the individual varietal character.
24

Spray Fabrication of Layer-by-Layer Antimicrobial N-Halamine Coatings

Denis-Rohr, Anna 17 July 2015 (has links) (PDF)
Antimicrobial coatings in which the active agent (e.g. N-halamine) can regenerate activity represent a promising way to prevent microbial cross-contamination. A reported method for applying coatings containing antimicrobial N-halamines is layer-by-layer (LbL) application of polyelectrolytes, which form N-halamines upon cross-linking. Prior reports on dip layer-by-layer (LbL) fabrication have demonstrated the potential of this coating technology; however, spray LbL fabrication would enable more rapid coating and represents a more commercially translatable application technique. In this work, dip and spray LbL methods were used to coat polypropylene (PP) with N-halamine containing bilayers consisting of cross-linked polyethylenimine (PEI) and poly(acrylic acid) (PAA). Further experimentation with spray LbL fabrication used naturally occurring polyelectrolytes, chitosan and alginate. Materials were characterized using atomic force microscopy (AFM), ellipsometry, contact angle, fourier transform infrared spectroscopy, a chlorine content assay, and a dye assay for amine quantification. All methods of coating application exhibited a 99.999% (5-log) reduction against Listeria monocytogenes with application time for spray LbL taking less than 10% of the time required for dip LbL. Spray LbL fabrication of N-halamines is a rapid and inexpensive method to fabricate rechargeable antimicrobial surfaces.
25

DIETARY ANTIOXIDANT SUPPLEMENTATION (ECONOMASE–BIOPLEX) TO ALLEVIATE ADVERSE IMPACTS OF OXIDIZED OIL ON BROILER MEAT QUALITY: A CHEMICAL, TEXTURAL, ENZYMATIC, AND PROTEOMIC STUDY

Delles, Rebecca 01 January 2013 (has links)
This study investigated the influence of dietary antioxidants and quality of oil on the oxidative and enzymatic properties of chicken broiler meat stored in an oxygen-enriched package (HiOx: 80% O2/20% CO2) in comparison with air-permeable polyvinylchloride (PVC) or skin (SK) packaging systems during retail display 2–4 °C for up to 14, 7, and 21 d, respectively. Broilers were fed a diet either with a low-oxidized oil (peroxide vale POV 23 meq O2/kg) or with a high-oxidized oil (POV 121 meq O2/kg), supplemented with an antioxidant pack (200 ppm EconomasE and organic minerals Se, Zn, Cu, Mn, and Fe as in Bioplex) in substitution for vitamin E and inorganic minerals for 42 d. In all packaging systems, lipid oxidation and protein oxidation were inhibited by up to 65% with an antioxidant-supplemented diet when compared to diets without antioxidant supplements. Antioxidant enzyme activities were significantly higher (P < 0.05) in the antioxidant-supplemented diets compared with control diets, regardless of oil quality. Meat samples from the antioxidant-supplemented group, irrespective of oil quality, has less purge and cooking loss compared to control diets. In all packaging systems, meat shear force was higher (P < 0.05) for broilers fed high-oxidized diets than the low-oxidized groups. Comparison between muscle types (breast as white vs. thigh as red) showed a similar trend in muscle susceptibility to oxidized oil in the diet but greater protection of antioxidant supplements for thigh meat in both physiochemical and textural properties. Dietary regimen influenced protein expression in broiler breast meat. Three protein spots from 2-dimensional gel electrophoresis, identified by mass spectrometry as glyceraldehyde 3-phosphate dehydrogenase, creatine kinase, and heat shock protein beta-1 were over-abundant in muscle from low-oxidized diets. The differential proteomes that suggested down regulation of the genes encoding antioxidative proteins upon feeding oxidized oil may be implicated in the broiler meat quality deterioration during storage. In summary, feeding diets with poor oil quality increased the vulnerability of lipids and proteins to oxidation in broiler breast and thigh meat during refrigerated and / or frozen storage in various packaging conditions, yet these effects were alleviated upon dietary supplementation with antioxidants.
26

Urban Farm and Community Garden Hybrid Models: A Case Study of the Huerta del Valle Community Garden

Hochberg, Leah 17 May 2014 (has links)
This study examines models of community gardens and urban farms and determined a successful hybrid model for future implementation at the Huerta del Valle Community Garden. This was accomplished through analyzing the unique benefits and drawbacks of community gardens and urban farms as defined by the author, and then determining the components of each model that would maximize Huerta del Valle’s social and economic potential. Community gardens are defined in this thesis as places where community members can grow their own food in individual plots, and these spaces often contribute to community building, hands-on gardening education, and improved food access. Urban farms are defined as business models that produce food to sell to the community both to support the business and to improve community food access. Through research of existing community garden, urban farm, and hybrid models, the author determined that the most effective hybrid model includes intensive crop production, crop sales onsite as well as in farmers’ markets and delivery methods, a large community garden, and education programs for the community. The author then offered Huerta del Valle a potential model that includes these components as well as a store front, cooking lessons, value-added products, a Community Supported Agriculture program, and specific themed gardening classes. This complete model will potentially increase Huerta del Valle’s scope so it is able to improve healthy food access throughout Ontario while creating an enduring economic model.
27

Effect of Poor Sanitation Procedures on Cross-Contamination of Animal Species in Ground Meat Products

Chung, Sunjung 28 May 2019 (has links)
While the presence of ≥1% of an undeclared species in ground meat generally used as an indicator of intentional mislabeling as opposed to cross-contamination, the actual percent of undeclared species resulting from cross-contamination has not been experimentally determined. The objective of this study was to quantify the effect of sanitation procedures on the crosscontamination of animal species in ground meat products, using undeclared pork in ground beef. Pork (13.6 kg) was processed using a commercial grinder, then one of three sanitation treatments was completed (“no cleaning”, “partial cleaning”, or “complete cleaning”). Next, beef (13.6 kg) was ground using the same equipment. For “no cleaning,” beef was ground immediately after pork without any cleaning step; for “partial cleaning,” the hopper tray was wiped, and excess meat was taken out from the auger; for “complete cleaning,” all parts of the grinder were disassembled and thoroughly cleaned with water and soap. A 100-g sample was collected for each 0.91 kg (2 lb) of beef processed with the grinder and each sanitation treatment was tested twice. Real-time polymerase chain reaction (PCR) was used to quantify pork in ground beef. For “no cleaning,” the first 100-g sample of ground beef run through the grinder contained 24.42 ± 10.41% pork, while subsequent samples contained
28

The application of food-grade chitosan and another food-grade compound in coatings to control Tyrophagus putrescentiae (Schrank, Family: Acaridae) growth on dry-cured hams and their impact on dry-cured ham quality

Shao, Wenjie 11 May 2022 (has links)
The objective of this research was to evaluate if chitosan and another food-grade compound can be incorporated into food-grade coatings in conjunction with propylene glycol and polysaccharides to control Tyrophagus putrescentiae growth without affecting sensory attributes, water activity, and moisture content of dry-cured hams. Each coating solution was coated on ham cubes (2.5 × 2.5 × 2.5 cm3, n = 5/treatment) or infused in ham nets, and dry-cured ham cubes were wrapped in the ham nets prior to inoculation with 20 mixed-sex adult mites. Randomized complete block designs with two replications were utilized to evaluate the efficacy of treatments at controlling mite growth on dry-cured ham cubes. When CH was mixed with XG and infused into a net, fewer mites (15.7 and 21.0 mites) were on ham cubes (P < 0.05) in comparison to the control (211.2 mites). Results indicated that CH contributed to controlling mite growth since 1% XG alone did not control mite growth. Difference from control test results indicated that no sensory differences existed (NS) between CH-treated and control ham slices. The addition of a food-grade compound (SP or 24P) to the XG coatings enhanced mite control efficacy. When 1% SP was added to 1% XG, it effectively controlled mite growth in both coating and netting treatments. Increasing 1% SP to 2% SP did not significantly (NS) control mite growth in the coating solution but did control mite growth when infused in the net. Both coating and netting treatments with 2% 24P + 1% XG controlled mite growth. When 24P was the only ingredient in the treatment, both 1% and 2% 24P controlled mites when infused in the net. The addition of SP did not (NS) impact the sensory attributes of the dry-cured ham. The 2% 24P + 1% XG treatment differed in moistness (P < 0.05) when compared to the blind control, but the rating was still less than 2 (moderately different). Overall, results from these studies indicate that chitosan can potentially be added in coatings or ham nets as tools to control mites in an integrated pest management program for dry-cured hams.
29

Screening of Commercially Available Chlorine Based Sanitizers and their Efficacy in Reducing Microbial Load Levels of E. coli O157:H7 at High and Low Organic Load Environments

Martinez-Ramos, Paola 25 October 2018 (has links) (PDF)
The presence of postharvest sanitizers has shown to be an effective approach to reducing microbial cross contamination in agricultural washing operations. However, choosing an appropriate sanitizer can be challenging due to produce commodity, processing conditions and interference with organic load. Current research shows a wide variety of methods to mimic the organic load of vegetable processing conditions, with paddle mixing and blender as the most commonly used. Controlling and understanding the physiochemical properties of wash water is key in maintaining sanitizer efficacy. The effects of simulated wash water preparation method on the physiochemical properties were tested at 0 and 50 COD(mg/L) and no significant difference was observed. However, at high levels of organic load results showed a significant difference between turbidity values at 1,500 COD. Free residual chlorine titration methods were compared, using DPD-titrimetric and Iodometric method. Results showed a significant difference between titration methods in organic load heavy environments. Commercially available chlorine based sanitizers, Pure Bright™ Germicidal Bleach and Clorox® Germicidal Bleach, were compared to a concentrated solution of sodium hypochlorite. Pure Bright™ Germicidal Bleach showed to perform the best by reducing 7 log CFU/ml of E. coli O157:H7 after 30 seconds in no organic load environments, whereas Clorox Germicidal bleach was able to reduce 7 log CFU/ml of E. coli O157:H7 after 30 minutes. These studies aim to provide best management practices for small in medium growers in the implementation of antimicrobial solutions for the maintenance of water quality in postharvest washing solutions.
30

Identification of Species in Ground Meat Products Sold on the U.S. Commercial Market Using DNA-Based Methods

Kane, Dawn 01 May 2015 (has links)
Mislabeling of ground meat products is a form of food fraud that can lead to economic deception and interfere with dietary restrictions related to allergens or religious beliefs. In various parts of the world, including Ireland, Mexico and Turkey, high levels of meat mislabeling have been reported between 2000-2015. However, there is currently a lack of information regarding this practice in the United States. Therefore, the objective of this study was to test a variety of ground meat products sold on the U.S. commercial market for the presence of potential mislabeling. Forty-eight ground meat samples were purchased from online and local retail sources, including both supermarkets and specialty meat retailers. DNA was extracted from each sample in duplicate and tested using DNA barcoding of the cytochrome c oxidase subunit I (COI) gene. The resulting sequences were identified at the species level using the Barcode of Life Database (BOLD). Any samples that failed DNA barcoding went through repeat extraction and sequencing. Due to the possibility of a species mixture, these samples were also tested with real-time polymerase chain reaction (PCR) targeting beef, chicken, lamb, turkey, pork and horse. Of the 48 products analyzed in this study, 10 were found to be mislabeled, with nine containing multiple meat species. Meat samples purchased from online specialty meat distributors had a higher rate of being mislabeled (35%) compared to samples purchased from a local butcher (18%) and samples purchased at local vii supermarkets (5.8%). Horsemeat, which is illegal to sell on the U.S. commercial market, was detected in two of the samples acquired from online specialty meat distributors. Overall, the mislabeling detected in this study appears to be due to reasons such as intentional mixing of lower-cost meat species into higher cost products or unintentional mixing of meat species due to cross-contamination during processing.

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