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Effects of Capture and Return on Chardonnay (Vitis vinifera L.) Fermentation VolatilesHodson, Emily 22 October 2004 (has links)
Effectiveness of a capture and return system for the partial retention of fermentation volatiles, as a means of improving white wine quality, was evaluated. Twenty-three aroma-active volatiles including ethyl esters, acetate esters, fusel alcohols, and fatty acids, were quantified using head-space solid phase microextraction with GC/MS. Volatile analysis of fermentations maintained at 15ºC demonstrated a trend of increased concentrations of ethanol, esters and ethyl esters of fatty acids and decreased concentrations of fusel alcohol acetates, fatty acids and higher alcohols in treatment wines. When fermentation temperature was maintained at 15ºC there was increased concentration and retention of fusel alcohols, fatty acids and higher alcohols compared to 15ºC. Sensory analysis of wines fermented at 15°C, using triangle difference testing, indicated variable differences in aroma among treatments. / Master of Science
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Yogurt as a Vehicle for Omega-3 Fatty Acid EnrichmentRognlien, Marnie 19 May 2010 (has links)
Consumer interest in supplementation with healthy omega-3 fatty acids (Ï 3 FA) has led to increased research in fortification of popular foods with these healthy fats. Yogurt, which is already popular, offers a functional food matrix to fortify with Ï 3 FA. Fish oil, a major source of two important long chain Ï 3 FA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is an excellent source of Ï 3 FA enrichment into foods but brings problems of oxidation and off-flavors or odors when added to foods. Encapsulation, deodorized fish oil, and flavoring have been investigated to reduce these off-flavors and odors in food products while producing a fish oil-fortified yogurt.
Discrimination of butter, fish or oxidized fish oil at 0.5% (wt/wt) levels was investigated in unflavored low-fat (1%) yogurt using untrained panelists (n=31) and sensory triangle tests. Five sensory attributes (lime, sweet, heat, acid, oxidized) were analyzed by experienced sensory panelists (n=12) in chile-lime flavored yogurts with butter, fish or oxidized fish oils added at low (0.43%) and high (1% wt/wt) levels. Analytical analysis for composition, fatty acid profile, and volatile chemistry of the yogurts was conducted. Consumer acceptance of a low-fat (1.5%) chile-lime flavored yogurt enriched with fish oil was investigated using a 9-point hedonic scale (1="dislike extremely", 9="like extremely").
Untrained panelists (n=31) were unable to differentiate 0.5% (wt/wt) levels of fish and butter oils in unflavored yogurts but were able to detect oxidized fish oil compared to butter or fish oil under in the same conditions. Experienced panelists (n=12) found significant differences (p<0.05) in lime and acid attributes in chile-lime flavored yogurts containing 1% (wt/wt) oxidized fish oil compared with 0.43 and 1% (wt/wt) butter and fish oil yogurts and 0.43% (wt/wt) oxidized fish oil yogurts. Oxidized attributes were determined as significantly different (p<0.05) by experienced panelists in chile-lime yogurts with 1% (wt/wt) fish oil, 0.43 and 1% (wt/wt) oxidized fish oil added. The acceptance of a fish oil-enriched chile-lime flavored yogurt was neutral ("neither liked nor disliked") by consumers (n=100) but 44% rated the product "like slightly" (6 of 9) or greater. A successful chile-lime flavored yogurt offering a novel savory flavor was formulated from pre-pasteurization addition of fish oil to deliver more than 145 mg DHA+EPA/170 g serving of yogurt. / Master of Science
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Chemical Identification and Flavor Profile Analysis of Iodinated Phenols Produced From Disinfection of Spacecraft Drinking WaterMirlohi, Susan 16 January 1998 (has links)
The National Aeronautics and Space Administration (NASA) is considering the use of iodine for disinfection of recycled wastewater and potable water in the International Space Station (ISS). Like Chlorine and other halogen compounds, iodine can form disinfection by-products (DBPs) in the presence of organic compounds. Recycled wastewater sources proposed for reuse in the space station include laundry, urine, and humidity condensate. These contain large concentrations of iodine-demanding compounds, including phenol (Barkely et al., 1992). Therefore, the potential for the formation of iodine disinfection by-products (IDBPs) is of concern.
Based on the characteristics of the ISS recycled wastewater sources and potable water treatment system, a series of experiments was designed to evaluate the formation of IDBPs under different experimental conditions. Studies were conducted by reacting various concentrations of iodine with phenol at pH 5.5 and 8.0.Iodine concentrations of 10 and 50 mg/L and phenol concentrations of 5 and 50 mg/L were used. Reactions were monitored for up to 32 days for the formation of IDBPs. All reactions were maintained at 20 C in dark. High Performance Liquid Chromatography (HPLC) and Gas Chromatography/Mass Spectrometry (GC/MS) were used for identification and quantitative analysis of phenolic compounds. Spectrophotometry was used to monitor the iodine concentrations. Falvor Profile analysis (FPA) method was used to evaluate the odor characteristics of the phenolic compounds.
Reactions of iodine with phenol resulted in the formation of the following by-products: 2-iodophenol, 4-iodophenol, diiodophenols, and 2,4,6-triiodophenol. Most reaction conditions studied resulted in the formation of all or some of the specified iodophenols. The initial mass ratio of iodine to phenol was the major determining factor in the concentrations and types of by-products formed. The IDBPs were formed within one hour after initiation of the reactions. Extended reaction times did not lead to significant increases in the concentration of IDBPs. Under most reaction conditions, mono-subsituted phenols were detected at significantly higher concentrations than di-substituted phenolic compounds; triiodophenol was the major by-product when iodine:phenol mass ratio was 10:1. The greatest number of IDBPs were formed when reaction solutions consisted of 1:1 mass ratio of iodine to phenol. FPA panel indicated the odor threshold concentrations for phenol, 2-iodophenol, and 4-iodophenol were 5 mg/L, less than 1 ug/L, and 1 mg/L respectively. The most common odor descriptions for all these compounds were "chemical", "phenolic", and "medicinal". / Master of Science
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Using Flavor Chemistry, Sensory, and Texture to Determine Domestic Edamame QualityMiller, Rebekah Jane 23 May 2024 (has links)
Persistent interest in edamame, vegetable soybean (Glycine max (L.) Merr.), by U.S. consumers has continued to fuel the development of a domestic edamame supply chain. Studies have shown edamame to be a nutritious specialty crop with potential to provide economic benefit to local growers. Domestically bred and grown edamame has shown to be preferred by growers and consumers with competitive agronomic traits. While domestic varieties of edamame will encourage growers to produce a product catered towards the domestic market, additional considerations of final product quality are necessary to positively influence the market success.
Domestically grown and store-bought edamame samples were utilized to research quality attributes including flavor, taste, and texture of edamame representative of domestic market and supply chain. Solid phase microextraction was utilized for aroma extraction prior to gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) analyses to obtain (1) impactful volatile compounds present, (2) changes in these compounds by stink bug feeding injury, and (3) volatile contributions to sensory characteristics. Sensory methods were utilized to (1) evaluate differences in perception of edamame with and without stink bug feeding injury, and (2) understand important sensory characteristics for domestic edamame.
Volatile analysis recognized 16 volatile compounds when investigating edamame genotypes with 14 compounds having significant differences in contents by genotype. Only 10 compounds were consistently detected through GC-O by panelists, so called aroma-active compounds, and only one compound (E)-2-octenal was significantly different in odor intensities across genotypes. Stink bug injured samples showed dramatic differences in volatile profile compared with the not injured counterpart, from mass chromatogram; however, no noticeable differences were perceived by GC-O or sensory difference testing. An instrumental texture analysis method was proven to be sensitive enough to detect the textural differences of edamame beans after processing. The multi-dimensional sensory characteristics including taste, aroma, and texture, were established showing significant differences by edamame variety and growing location. Domestically bred edamame was found to be sweeter, as is preferred by domestic consumers, confirming encouraging breeding outcome. Despite significant differences in edamame volatile profiles by genotype and stink bug feeding injury, sensory discrimination of these differences seems to be less noticeable than changes from taste and texture. Utilizing our findings toward future research and product development will support the domestic edamame supply chain by providing a foundational understanding of quality attributes and their impacts. / Doctor of Philosophy / Edamame, or vegetable soybean (Glycine max (L.) Merr.), has been gaining popularity in the U.S. as plant based and alternative proteins continue to see increased attention. Research has shown edamame to be a nutritious specialty crop with potential to provide economic benefit to local growers. Edamame developed and grown in the U.S. has been shown to be preferred by growers and consumers. Understanding the quality of these products is important for a positive and lasting presence in the market.
In this work, locally grown edamame as well as storebought edamame were investigated for flavor and texture. Chemistry methods to research volatile compounds were used to determine impactful flavor compounds, changes in these compounds caused by stink bug injury, and specific aroma of these compounds in edamame. Sensory methods were used to determine differences in edamame injured by stink bugs and to determine taste, flavor, and texture terms related to local edamame.
This work identified 16 volatile compounds consistently in edamame samples with 14 being found to vary in amount by edamame genotype. Only 10 volatile compounds were detected through human sniffing results with only one being found to vary in amount of aroma detected by edamame genotype. Edamame showing visual signs of stink bug feeding injury showed different amounts of chemical compounds compared to the uninjured edamame, but aroma detected by human sniffing and sensory evaluation did not show differences. A method using a texture instrument was proven to be sensitive enough to detect even minor differences of edamame beans by texture. Sensory qualities including taste, aroma, and texture, were found to have differences in edamame based on edamame variety and growing location of the edamame. Locally bred and grown edamame was found to be sweeter than comparable edamame, as is preferred by consumer in the U.S. Despite differences in volatile compounds in edamame as identified in volatile analysis by differences in stink bug feeding injury, edamame genotype, and growing location, detection of these differences through aroma and taste by human panelists is not seen in this work. Providing these understanding of sensory qualities and their impact on the edamame will help support the local edamame supply in decision making and product development.
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The effect of two reheating methods and storage on the development of warmed-over flavor in precooked chicken partsGiuffrida, Michelle L. January 1993 (has links)
This study was conducted to determine the effect of heating methods (conventional and microwave), heating temperatures, and refrigerated storage on the flavor deterioration in precooked chicken parts. Chicken breasts and legs were evaluated by chemical analyses and sensory evaluation. Data was analyzed by Fisher's least significant difference (LSD) and Duncan's test.
Results of the thiobarbituric acid test (TBA) indicated that heating temperature, regardless of heating method had a significant influence on oxidative deterioration. When the legs were heated for a longer time at a lower temperature, the TBA values significantly increased indicating heightened warmed-over flavor (WOF). Two-day refrigerated storage had no measurable influence on the TBA numbers. The legs generally had a higher degree of lipid oxidation reflected by higher TBA values.
Heating method and 2-day refrigerated storage did not have a significant effect on the nonheme iron content of breasts or legs. The effects of heating temperature were inconsistent for the legs and breasts which was attributed to the different initial iron content of the legs, and the release of nonheme iron during the initial processing of the legs. The nonheme iron values of the legs were greater relative to the breasts.
Heating and storage in general increased the area of peak 3 in legs, but had no effect on the breasts. A significant increase in the hexanal (peak 8) content of legs occurred upon 2-day storage, but not for breasts. Peak 7 significantly decreased when the breasts were heated, stored, and reheated. This was not the case for the legs. Sensory panelists could not differentiate between heating methods or temperatures for either part. / Master of Science
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Economics and risk of catfish production strategiesCheatham, Morgan Christine 10 May 2024 (has links) (PDF)
US catfish producers, seeking to reduce production costs, adopted technologies and production systems with the potential to increase the catfish pond productivity. Catfish pond intensification was accompanied by increased operating risk due to increased reliance on operating inputs. Split ponds were one adopted production system. The US catfish industry has adopted four split-pond variants differentiated by water circulation mechanism. Variants include the slow-rotating paddlewheel, the modified paddlewheel aerator, the screw pump, and the axial-flow turbine pump. Initial investment ranged from $54,400/4-ha ponds to $71,150/4-ha pond. Mean annual gross fish yield ranged from 12,876 kg/ha to 16,984 kg/ha. Net returns were positive for all designs under current economic conditions. The modified paddlewheel aerator and slow-rotating paddlewheel designs show the most promise for adoption. US catfish producers use multiple production strategies of varying intensity level, species produced, and pond design. Commercial farm data were used to quantify the economic risk of six commonly used catfish production strategies. Second order stochastic dominance (SOSD) was exhibited by multiple-batch and intensively aerated production of channel catfish over low intensity culture of channel catfish. Higher intensity hybrid catfish production strategies exhibited SOSD over medium intensity culture of hybrid catfish. Variations in fish yield, feed price, and feed conversion ratio were the primary contributors to variations in production cost. Hybrid catfish production strategies were dominated by yield (production) risk and channel catfish production strategies were dominated by price (market) risk. Off-flavor has been a persistent problem in the US catfish industry and contributes to economic risk. The cost of off-flavor was quantified at the farm level. A survey of catfish producers carried out in 2022 (n=54) revealed that farms representing 85% of the foodfish production area followed management practices for curbing off-flavor. The average annual off-flavor prevalence and the associated processing plant sample rejection rate was 27%. Off-flavor caused harvest delays averaged 23 days. Copper sulfate and diuron were used for managing off-flavor with diuron being the most popular choice used on 78% of the surveyed area. Direct annual cost associated with off-flavor management on catfish farms amounted to $39.9 million ($2,325/ha or $0.272/kg) in 2022.
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Utilization of a liquid smoke fraction as a reactionary, caramel-type flavor in whipped cream applications via Maillard reaction mechanismsSnow, Alison R. January 1900 (has links)
Master of Science / Food Science Institute - Animal Science & Industry / Fadi M. Aramouni / Smoke flavored foods continue to be a popular choice among consumers. In this study, a caramel-type flavor in whipped cream applications via Maillard reaction pathways was evaluated. A highly refined liquid smoke fraction was developed using a delignified pulp wood source, and a patented activated carbon filtration process. To maximize sensory and reactionary capabilities, a liquid smoke fraction with phenol and carbonyl concentrations of 0.07mg/ml and 12.9g/100ml, respectively, was developed. Heavy cream containing a 0.075% addition of the refined liquid smoke fraction was evaluated when reacted at 50, 63, and 72°C for 15 sec prior to chilling at 0°C for 12 h, and whipping for 8 min using a handheld mixer. Sensory analysis showed the addition of liquid smoke increased whipped cream sweetness and caramel flavors, while imparting minimal off-flavors. Probable Maillard pathways were predicted for the reaction taking place between the liquid smoke and the dairy proteins upon thermal processing. This technology can be used to develop other foods which are not traditionally smoke flavored.
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Flavor comparison of ultra high temperature processed milk heated by Ohmic heating and conventional methodsHe, Juan 20 March 2012 (has links)
Ultra high temperature (UHT) processing can extend shelf life of milk to several months without refrigeration, which is more convenient and energy saving than pasteurized milk. However, the poor acceptance caused by "cooked" flavors limits its marketing growth, especially in United States. Ohmic heating, which has a more uniform and rapid heating than conventional UHT process, may minimized the flavor change during the thermal treatment. Flavor composition between Ohmic heated UHT milk and other traditionally processed UHT milk (direct steam injection and indirect plate heating) during 36 weeks storage were investigated in this study. A total of 20 volatile compounds were analyzed based on their importance to UHT milk as well as their representation to different chemical classes including sulfur-containing compounds, ketones, lactones, aldehydes and others. Dimethyl sulfide (DMS) and methyl ketones were significant different among three types of UHT heated milk. δ-lactones showed higher amount in Ohmic heating after stored for four weeks, which might generate creamy, fruity intermediate aroma. Other compounds showed no significant difference among three heating processes. Aroma recombination test revealed that the overall aroma of the ultra pasteurized (UP) milk could be mimicked by recombining 15 important reference odorants in the same concentrations as they occurred in the UHT milk using commercial pasteurized milk as the matrix. / Graduation date: 2012
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Flavor Changing Neutral Current Processes In The Framework Of The Two Higgs Doublet ModelTuran, Ismail 01 January 2003 (has links) (PDF)
It is widely believed that the Standard Model (SM) can not be a fundamental
theory of the basic interactions. Originated from this fact, many new physics
models have been proposed. Among them, the two Higgs doublet model (2HDM),
the SM enlarged by adding one extra scalar doublet, is considered as the simplest extension of the SM.
In this work, within the framework of the model III version of the 2HDM,
the exclusive decay the branching ratio is calculated and discussed in various physical regions determined by model parameters. It is
observed that it is possible to reach present experimental upper limits in model Finally, the
avor changing top quark decay,
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Characterizing cosmic neutrino sources / a measurement of the energy spectrum and flavor composition of the cosmic neutrino flux observed with the IceCube Neutrino ObservatoryMohrmann, Lars 30 November 2015 (has links)
Das IceCube Neutrino Observatorium ist ein km^3-großes Neutrinoteleskop und befindet sich am geographischen Südpol. Das Ziel des Experiments ist es, kosmische Neutrinos nachzuweisen. Es wird erwartet, dass solche Neutrinos in Wechselwirkungen von hochenergetischer kosmischer Strahlung mit Materie oder Photonen in der Nähe ihrer Beschleunigungsumgebung entstehen. Der erste Nachweis für einen Fluss von kosmischen Neutrinos wurde von der IceCube-Kollaboration erbracht. Der Ursprung des Flusses ist noch nicht bekannt, dennoch können die Eigenschaften der Quellen durch eine Messung des Energiespektrums und der Zusammensetzung aus Elektron-, Muon-, und Tau-Neutrinos des Flusses eingeschränkt werden. Die vorliegende Arbeit stellt die erste umfassende Analyse von Daten des IceCube-Experiments im Hinblick auf diese Eigenschaften des Flusses dar. Hierfür wurden mehrere Datensätze kombiniert und gemeinsam analysiert. Es wurden experimentell beobachtete Verteilungen von rekonstruierter Energie, Zenithwinkel und Teilchen-Signatur mit Modellverteilungen angepasst. Unter der Annahme, dass der Fluss isotrop ist und zu gleichen Teilen aus allen Neutrino-Flavors besteht, wird das Spektrum durch ein Potenzgesetz mit Normalisierung (6.7_{-1.2}^{+1.1})x10^{-18}GeV^{-1}s^{-1}sr^{-1}cm^{-2} bei 100 TeV und spektralem Index -2.50+-0.09 zwischen Neutrino-Energien von 25 TeV und 2.8 PeV gut beschrieben. Ein spektraler Index von -2 kann mit einer Signifikanz von 3.8 Standardabweichungen ausgeschlossen werden. Die Flavor-Zusammensetzung ist kompatibel mit Erwartungen für Standard-Prozesse der Neutrino-Produktion. Die ausschließliche Produktion von Elektron-Neutrinos kann hingegen mit einer Signifikanz von 3.6 Standardabweichungen ausgeschlossen werden. Unter der Annahme, dass die Neutrino-Flavor während der Propagation von den Quellen zur Erde durch Standard-Neutrino-Oszillationen transformiert werden, beträgt der gemessene Anteil an Elektron-Neutrinos an der Erde (18+-11)%. / The IceCube Neutrino Observatory is a km^3-sized neutrino telescope located at the geographical South Pole. Its primary purpose is the detection of high-energy cosmic neutrinos. Such neutrinos are expected to be produced in interactions of high-energy cosmic rays with ambient matter or photons close to their acceleration sites. The IceCube Collaboration has reported the first evidence for a flux of high-energy cosmic neutrinos. While the origin of the flux remains unknown so far, the properties of its sources can be constrained by measuring its energy spectrum and its composition of electron, muon, and tau neutrinos. The present work constitutes the first comprehensive analysis of IceCube data with respect to these principal characteristics of the flux. Several data sets were assembled and simultaneously studied in a combined analysis. Experimentally observed distributions of reconstructed energy, zenith angle and particle signature were fitted with model distributions. Assuming the cosmic neutrino flux to be isotropic and to consist of equal flavors at Earth, the all-flavor spectrum is well described by a power law with normalization (6.7_{-1.2}^{+1.1})x10^{-18}GeV^{-1}s^{-1}sr^{-1}cm^{-2} at 100 TeV and spectral index -2.50+-0.09 for neutrino energies between 25 TeV and 2.8 PeV. A spectral index of -2 is disfavored with a significance of 3.8 standard deviations. The flavor composition is compatible with that expected for standard neutrino production processes at the sources. However, a scenario in which only electron neutrinos are produced is disfavored with a significance of 3.6 standard deviations. Assuming that standard neutrino oscillations transform the neutrino flavors during propagation from the sources to the Earth, the measured fraction of electron neutrinos at Earth is (18+-11)%.
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