Thesis--University of California, Berkeley, 1959. / "Chemistry General" -t.p. "TID-4500 (15th Ed.)" -t.p. Includes bibliographical references (p. 38-39).

This thesis deals with the development of high performance liquid chromatography method (HPLC) for the determination of propionic acid in bakery products. This work is resulting from the requirements and conditions of Czech Agriculture and Food Inspection Authority (CAFIA) laboratory in Brno. The theoretical part of the thesis describes properties, production, metabolism, toxicity and preservative effect of propionic acid. Furthermore it is treating about HPLC, validation of some analytical method and methods of propionic acid determination. Experimental part is focused on the propionic acid determination in the major part of available products with this preservative on the Czech market. Propionic acid was extracted from the sample with water, filtered and the filtrate was analyzed directly by HPLC. Separation was performed on a XBridge C18 column (3 x 150 mm, 3,5 µm) with a mobile phase of phosphate buffer (pH adjusted to 2,8) and UV detection at 210 nm. Used method of propionic acid isolation was compared with repeated extraction method, extraction in the mobile phase solution and steam destilation both in commercial samples and in laboratory baked breads with known addition of propionic acid. HPLC with water extraction technique was evaluated as a suitable method for propionic acid determination in bakery products.

No description available.

No description available.

The arid conditions found in the west allow for the production of high quality hay for export. However, hay production in this region is highly dependent upon irrigation. There is significant interest in developing a hay export market in the eastern U.S. Therefore, a greater understanding of the challenges and opportunities with containerizing hay in high humidity environments is needed. The objective of this study was to evaluate the impact of hay preservatives on the stability of containerized hay. Treatments included 1) propionic acid at baling, 2) propiopnic acid at baling + surface applied propionic acid at container loading, 3) propionic acid at baling + ammonization of the container after loading, and 4) no preservatives. Propionic acid was applied at a rate of 2.5 kg Mg-1 of hay at baling to all treatments except the control. Hay was then stored for 5 weeks before compressing to a density of 320.0 kg m-3. Immediately before containerizing hay, treatment 2 received a surface application of propionic acid at a rate of 3.4 g bale-1. After loading hay into containers, treatment 3 was ammoniated at a rate of 1.5 kg NH3 Mg-1 DM. Temperature and relative humidity in the containers were monitored for the 45-day storage period. Hay was sampled at compression and immediately after opening the containers. There were no treatment effects on nutritive value parameters after containerization (P > 0.05). Neither propionic acid at harvest, nor treatments at containerization had an effect on mold development in this study (P > 0.05). / Master of Science

Clinical studies reported side effects of muscular spasms and muscle stiffness following the administration of clofibrate, a drug once used to treat hyperlipidaemia in patients. Experiments with clofibrate and its analogues in animal models showed it produced these myotonic symptoms in muscle by reducing the chloride conductance of the muscle membrane. The effects of 2-(4-chlorophenoxy)propionic acid, an analogue of clofibric acid, was assessed on the rat ClC-1 channel (rClC-1). Racemic 2-(4-chlorophenoxy)propionic acid shifted the voltage dependence of rClC-1 activation to more depolarising potentials, a mechanism accounting for myotonic symptoms previously reported. Experiments with resolved enantiomers revealed that the effects recorded were due exclusively to S-(–) 2-(4- chlorophenoxy)propionic acid. The R-(+) enantiomer was ineffective at the concentrations tested. Further experiments with the compound at differing Cl- concentrations in the extracellular solution suggested that S-(–) 2-(4-chlorophenoxy)propionic acid altered the gating of ClC-1 by decreasing the affinity of the binding site where Cl- normally acts to ‘gate’ the channel. Similarities in the effects reported for most dominant mutations in the CLCN1 gene that lead to myotonia congenita and 2-(4-chlorophenoxy)propionic acid prompted experiments that introduced these point mutations in the human ClC-1 (hClC-1) gene to compare their mode of action to that of the drug. These mutations, F307S and A313T, predominantly altered the slow, or common, gate of the channel. Conversely, the effect of 2-(4-chlorophenoxy)propionic acid was predominantly on the fast gating process of hClC-1. A macroscopically similar effect therefore, can be produced by two different modes of action. Results suggested that both drug and mutations exert their action by affecting the transition of the channel from its closed to open state subsequent to Cl- binding. Investigation of the interaction between rClC-1 gating and a further 25 compounds structurally related to clofibric acid identified a number of compounds effective at shifting the open probability of fast gating to depolarising potentials. Fewer were identified that influence slow gating. Some compounds affected both gating processes, however, none were identified which influenced slow gating alone. Ability to displace the voltage dependent activation of the fast gate appeared to depend largely on the lipophilicity of the molecules tested, indicating the importance of hydrophobic interactions between drug and channel protein. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1474724 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2009

No description available.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Made available in DSpace on 2014-06-11T19:26:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-08-27Bitstream added on 2014-06-13T20:07:31Z : No. of bitstreams: 1 nogueira_m_me_jabo.pdf: 312466 bytes, checksum: 35911aabc16eaed3bdb8cdcf9639b954 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Foram realizados dois experimentos com o objetivo de avaliar o efeito da ureia e do ácido propiônico na fenação e ensilagem do capim – tifton 85. No primeiro experimento foram confeccionados três tratamentos das silagens emurchecidas: controle não aditivada (SEC), aditivada com ácido propiônico (SEAP) e aditivada com ureia (SEU), bem como três tratamentos de feno: controle (FC), feno de alta umidade aditivado com ácido propiônico (FAUAP); feno de alta umidade aditivado com ureia (FAUU). Foi avaliada a composição bromatológica dos fenos e das silagens pré secadas no momento após a aplicação dos aditivos e após 60 dias de armazenamento. A utilização da ureia como aditivo nas silagens pré secadas e fenos alterou a composição bromatológica destes por meio da redução dos constituintes da parede celular e preservação dos teores de proteína bruta. No segundo experimento objetivou-se avaliar os efeitos da aplicação de aditivos químicos nos fenos de capim - tifton 85 sobre a alimentação de ovinos. Foram avaliados três tratamentos: Feno controle (FC), feno aditivado com ácido propiônico (FAP) e feno aditivado com ureia (FU). Foram utilizados 30 cordeiros, machos, não castrados, mestiços Santa Inês x Dorper, sendo avaliados a composição bromatológica dos fenos, o consumo de matéria seca e de nutrientes, o ganho de peso e as características da carcaça dos ovinos confinados. As dietas compostas com os diferentes fenos não diferiram (P>0,05) quanto à digestibilidade in vivo, consumo de nutrientes, ganho de peso, os valores de rendimento verdadeiro, porcentagens dos cortes comerciais da meia carcaça esquerda, pH, temperatura, área de olho de lombo e espessura de gordura dos cordeiros. A adição dos aditivos não trouxe benefícios ao feno de Tifton 85 / Two experiments were conducted in order to evaluate the effect of urea and propionic acid in Tifton 85 hay and silage. In the first experiment was evaluated three haylages: control- without additives (SEC), treated with propionic acid (SEAP) and treated with urea (SEU) and three high dry matter hays: control (FC), treated with propionic acid (FAUAP) and treated with urea (FAUU). Chemical composition of the haylage and hay were evaluated at the time after the additives application, and after 60 days of storage. The use of urea as an additive in haylage and hay changed the chemical composition of these through the reduction of cell wall constituents and preservation of crude protein. The second experiment aimed to evaluate the effects of application of chemical additives in Tifton 85 hay on the feeding of sheep. Three treatments were evaluated: control (FC), treatment with propionic acid (FAP) and treatment with urea (FU). In the trial 30 lambs, male, not castrated, crossbred Dorper x Santa Inês, were used to evaluate the dry matter and nutrients intake, digestibility, daily weight gain and carcass characteristics of feedlot sheep. The diets with different hay did not affect (P>0,05) the in vivo digestibility, nutrient intake, weight gain, and the values of real income, percentage of retail cuts from the left half carcass, pH, temperature, loin eye area and fat content. Chemical additives did not bring benefits to Tifton 85 haylage or hay

Orientador: Gustavo Rezende Siqueira / Banca: Ana Claudia Ruggieri / Banca: Thiago Fernandes Bernardes / Resumo: Foram realizados dois experimentos com o objetivo de avaliar o efeito da ureia e do ácido propiônico na fenação e ensilagem do capim - tifton 85. No primeiro experimento foram confeccionados três tratamentos das silagens emurchecidas: controle não aditivada (SEC), aditivada com ácido propiônico (SEAP) e aditivada com ureia (SEU), bem como três tratamentos de feno: controle (FC), feno de alta umidade aditivado com ácido propiônico (FAUAP); feno de alta umidade aditivado com ureia (FAUU). Foi avaliada a composição bromatológica dos fenos e das silagens pré secadas no momento após a aplicação dos aditivos e após 60 dias de armazenamento. A utilização da ureia como aditivo nas silagens pré secadas e fenos alterou a composição bromatológica destes por meio da redução dos constituintes da parede celular e preservação dos teores de proteína bruta. No segundo experimento objetivou-se avaliar os efeitos da aplicação de aditivos químicos nos fenos de capim - tifton 85 sobre a alimentação de ovinos. Foram avaliados três tratamentos: Feno controle (FC), feno aditivado com ácido propiônico (FAP) e feno aditivado com ureia (FU). Foram utilizados 30 cordeiros, machos, não castrados, mestiços Santa Inês x Dorper, sendo avaliados a composição bromatológica dos fenos, o consumo de matéria seca e de nutrientes, o ganho de peso e as características da carcaça dos ovinos confinados. As dietas compostas com os diferentes fenos não diferiram (P>0,05) quanto à digestibilidade in vivo, consumo de nutrientes, ganho de peso, os valores de rendimento verdadeiro, porcentagens dos cortes comerciais da meia carcaça esquerda, pH, temperatura, área de olho de lombo e espessura de gordura dos cordeiros. A adição dos aditivos não trouxe benefícios ao feno de Tifton 85 / Abstract: Two experiments were conducted in order to evaluate the effect of urea and propionic acid in Tifton 85 hay and silage. In the first experiment was evaluated three haylages: control- without additives (SEC), treated with propionic acid (SEAP) and treated with urea (SEU) and three high dry matter hays: control (FC), treated with propionic acid (FAUAP) and treated with urea (FAUU). Chemical composition of the haylage and hay were evaluated at the time after the additives application, and after 60 days of storage. The use of urea as an additive in haylage and hay changed the chemical composition of these through the reduction of cell wall constituents and preservation of crude protein. The second experiment aimed to evaluate the effects of application of chemical additives in Tifton 85 hay on the feeding of sheep. Three treatments were evaluated: control (FC), treatment with propionic acid (FAP) and treatment with urea (FU). In the trial 30 lambs, male, not castrated, crossbred Dorper x Santa Inês, were used to evaluate the dry matter and nutrients intake, digestibility, daily weight gain and carcass characteristics of feedlot sheep. The diets with different hay did not affect (P>0,05) the in vivo digestibility, nutrient intake, weight gain, and the values of real income, percentage of retail cuts from the left half carcass, pH, temperature, loin eye area and fat content. Chemical additives did not bring benefits to Tifton 85 haylage or hay / Mestre