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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.
221

Estudo da vida útil de cortes suínos com osso (bisteca e costela) acondicionados em atmosfera modificada / Shelf life studies on pork cuts with bone in (chops and ribs) packed under different modified atmosphere gas composition

Boldrin, Melissa Cássia Favaro 28 January 2008 (has links)
Atualmente os supermercados vêm utilizando para a exposição de carnes frescas, bandejas rígidas revestidas de filmes plásticos permeáveis a gases. Esse sistema protege a superfície da carne de possíveis contaminações e permite a seleção dos cortes pelo consumidor. No entanto, essa forma de acondicionamento limita a vida útil da carne, especialmente dos cortes com osso. Dessa maneira, o presente trabalho de pesquisa objetivou estudar a interação entre as diferentes tecnologias - embalagem com atmosfera modificada, ácidos orgânicos e antioxidante - aplicando-se diferentes concentrações de dióxido de carbono (CO2) combinado com o nitrogênio (N2) e monóxido de carbono (CO) (composições gasosas: C1: 99,6%CO2/0,4CO; C2: 19,6%N2/80%CO2/0,4%CO; C3: 49,6%N2/50%CO2/0,4%CO e C4: 50%CO2/50%N2;) e seus efeitos nas características físico-químicas, sensoriais e microbiológicas de bisteca e de costela suína, armazenadas a temperatura de 2+ 2 ºC por um período de 32 dias. Após a obtenção dos referidos cortes na sala de desossa, metade foram pulverizados com a solução de ácidos orgânicos (1% de ácido acético, 1% de ácido lático e 1% de ácido cítrico) e antioxidante (0,8% de ácido ascórbico), e a outra metade não foi pulverizada. A seguir, as amostras pulverizadas ou não, foram colocadas em bandejas plásticas rígidas dentro de saco-filme impermeável a gases. O conjunto, produto mais bandeja foi submetido a três diferentes misturas gasosas, sendo C1, C2 e C3 para costela e C2, C3 e C4 para bisteca. Foram realizadas avaliações físico-químicas, microbiológicas e sensoriais nos 0 (caracterização da matéria-prima), 1º, 5º, 13º, 19º, 25º e 32º dias. Concluiu-se que o uso das composições gasosas: 19,6%N2/80%CO2/0,4%CO e 49,6%N2/50%CO2/0,4%CO, para a bisteca, e a três composições para costela, mantiveram a estabilidade da cor visual e instrumental da carne, do osso e da gordura durante todo o período de estudo. O odor foi predominantemente ácido em todas as amostras desde o primeiro dia de análise. As concentrações de CO2 usadas não foram efetivas na redução das contagens microbianas devido a elevada carga microbiana inicial da matéria-prima. Houve prevalência de bactérias láticas em todas as amostras após o 19º dia, e a vida útil foi de no mínimo 13 dias para todos os tratamentos. / Supermarkets have been using rigid trays covered with gas permeable films to expose fresh meat. This system keeps the meat surface free from contamination and allows the consumer choice, although this type of packaging shortens the meat shelf life, especially cuts with bone in. Thus, the aim of the present was to evaluate the interaction among the followed different technologies: modified atmosphere and spraying of organic acids with antioxidants solution in the meat surface. The effect of four types of modified atmosphere containing different carbon dioxide concentrations combined with nitrogen (N2) and carbon monoxide (CO) (C1: 99,6%CO2/0,4CO; C2: 19,6%N2/80%CO2/0,4%CO; C3: 49,6%N2/50%CO2/0,4%CO e C4: 50%CO2/50%N2) on physical, chemical, sensory and microbiological characteristics were evaluated in portioned pork chops and pork ribs stored during 32 days in a cooling chamber at 2+ 2 ºC. Half of the cuts obtained from the carcasses deboned at CTC were randomly assigned for spraying with a solution containing acetic acid (1%), lactic acid (1%), citric acid (1%) and ascorbic acid (0,8%) while the rest was not sprayed. Following, the samples were packaged in rigid plastic trays covered with impermeable film/bag and subjected to three different atmospheres (pork chops - C1, C2 and C3 and pork ribs - C2, C3 and C4). During storage the physical, chemical, microbiological and sensory evaluations were conducted in the following periods: 0 (raw material), 1, 5, 13, 19, 25 e 32 days. It was concluded that the use of following gas composition: 19,6%N2/80%CO2/0,4%CO and 49,6%N2/50%CO2/0,4%CO kept the color stability for pork chops and the three compositions for pork ribs, either subjective or objective, of the meat, bone and fat during all the period of the experiment. The odor was acid in all samples from the first day of analysis. The percentages of CO2 used in the experiment were not effective to reduce bacterial count because the raw material had high initial count. There was prevalence of lactic acid bacteria in all samples after the 19º day and shelf life was at least 13 days for all treatments.
222

Estudo da elasticidade-renda da demanda de carne bovina, suína e de frango no Brasil / Study of income-elasticity of beef, pork and poultry meat\'s demand in Brazil

Carvalho, Thiago Bernardino de 20 April 2007 (has links)
O Brasil possui um mercado interno potencial para o consumo de alimentos, principalmente para as carnes. A carne já faz parte da alimentação dos brasileiros e sua demanda está ligada a vários fatores, como preços, qualidade, aspectos nutricionais, preferência, gosto e, principalmente, a restrição orçamentária, ou seja, a renda. A fim de determinar o quanto a renda impacta o consumo de carnes, buscou-se no presente estudo estimar as elasticidades-renda da demanda de carne bovina, suína e de frango, no Brasil e suas regiões. As elasticidades foram obtidas por meio do ajustamento de uma poligonal com três segmentos. Os coeficientes de elasticidade-renda do dispêndio, calculados para as carnes de forma geral, foram sempre menores do que 1, sendo a carne bovina, responsável pelos valores extremos: a de primeira, próxima de 1 e a de segunda, próxima de zero. As altas elasticidades obtidas para a carne bovina de primeira e também para a carne suína indicam que há maiores aumentos nas despesas de ambas as carnes, quando há uma variação positiva na renda da população. Para a carne bovina de segunda e para a carne de frango o impacto é menor. Por fim, pode-se inferir, tendo-se observado em muitos casos elasticidades decrescentes de acordo com o aumento de renda, que uma redistribuição desta poderia levar a um aumento significativo do consumo de carnes. Este estudo pode fundamentar as estratégicas de mercado de empresas do setor de carnes, tanto industrial como varejistas. Verifica-se expansão na produção e exportação nos três mercados estudados e as elasticidades estimadas servem de base para análises prospectivas sobre o consumo doméstico. / Brazil has a potencial domestic market for food consumption, mainly for meat. Meat is already a part of the Brazilian eating habit and its demand is connected to several factors, like prices, quality, nutritional aspects, preferences, taste and, mainly, to budget restriction, that is, the income. To determine how much the income impacts on the meat consumption, this work estimated the income-elasticities of beef, pork and poultry meat demand in Brazil and its regions. The elasticities were obtained by fitting a three-segment polygonal curve. The income elasticities coefficients, calculated for meat, were always below 1, being beef responsible to extreme values: the beef of first quality is near 1 and the beef of second quality, near zero. The high elasticities for beef first and also for pork indicates that there are bigger increases in the expenditures of both kinds of meat, when there is a positive variation in the population income. To the beef of second quality and to the poultry meat the impact is smaller. Finally, the study infers, noticing in many cases decreasing elasticities according to the increasing income, that a redistribution of this could get a significative increase of the meat consumption. This study can base market?s strategies of meat companies, as industrial as retailer. It also shows expansion in the production and export in the three studied markets and the obtained elasticities can be used to the previous analysis about domestic consumption.
223

Uticaj procesa osmotske dehidratacije na prenos mase i kvalitet mesa svinja / The Effect of the Osmotic DehydrationProcess on Mass Transfer and Pork MeatQuality

Filipović Vladimir 23 May 2013 (has links)
<p>Ispitivan je proces osmotske dehidratacije mesa<br />svinja u tri osmotska rastvora (vodeni rastvor<br />natrijum hlorida i saharoze, kombinacija<br />vodenog rastvora natrijum hlorida i saharoze i<br />melase i melasa &scaron;ećerne repe) različitih<br />koncentracija, na tri temperature (20&deg;C, 35&deg;C i<br />50&deg;C) i pri tri vremena trajanja procesa (1, 3 i<br />5h). Mereni i računati odzivi procesa osmotske<br />dehidratacije bili su: sadržaj suve materije,<br />gubitak vode, prirast suve materije, indeks<br />efiksanosti procesa, vrednost aktivnosti vode.<br />Rezultati ispitivanja pokazuju da povećanje<br />tehnolo&scaron;kih parametara temperature i vremena<br />procesa, kao i koncentracije osmotskih rastvora<br />dovode do intenziviranja prenosa mase u<br />procesu i povećanja vrednosti odzivnih<br />parametara procesa, u oba slučaja, istostrujne i<br />protivstrujne osmotske dehidratacije.<br />Na osnovu dobijenih rezultata razvijeni su<br />modeli zavisnosti odziva procesa od<br />primenjenih tehnolo&scaron;kih parametara za<br />istostrujne i protivstrujne procese osmotske<br />dehidratacije. &ldquo;Score&rdquo; analizom određene su<br />vrednosti tehnolo&scaron;kih parametara koje su za<br />rezultat dale optimalnu efiksanost procesa.<br />U radu je ispitan enegetski bilans procesa<br />osmotske dehidratacije i upoređen sa<br />konvektivnim su&scaron;enjem, gde su se kao<br />energentski najefikasniji pokazali procesi na<br />temperaturi od 20&deg;C.<br />Karakteristike osmotski dehidriranog svinjskog<br />mesa su pokazale da dolazi do pobolj&scaron;anja<br />mikrobiolo&scaron;kog, hemijskog i nutritivnog profila<br />mesa nakon procesa, kao i promene boje i<br />teksture, gde je melasa &scaron;ećerne repe kao<br />osmotski rastvor, iskazala najbolje uticaje na<br />promene karakteristika dehidiranog mesa.<br />Na osnovu svih ispitanih uticaja variranih<br />parametara kao optimalni parametri procesa<br />mogu da se defini&scaron;u: protivstrujni proces, u<br />trajanju od 5 časova na temperaturi od 20&deg;C, u<br />melasi kao osmotskom rastvoru. Ovakav proces<br />dovodi do sveukupnog pobolj&scaron;anja<br />karakteristika svinjskog mesa uvodeći nutritivna<br />pobolj&scaron;anja iz hemijskog sastava melase u<br />ljudsku ishranu.</p> / <p>Process of osmotic dehydration of pork meat in<br />three different osmotic solutions (sodium<br />chloride and sucrose dissolved in water, mixture<br />of sodium chloride, sucrose dissolved in water<br />and molasses and sugar beet molasses) of<br />different concentrations, at three temperatures<br />(20&deg;C, 35&deg;C &amp; 50&deg;C) and three different times<br />of duration of the process (1, 3 &amp; 5h) was<br />investigated.<br />Measured and calculated responses of the<br />osmotic dehydration process were: dry matter<br />content, water loss, solid gain, dehydration<br />efficiency index and value of water activity.<br />The results showed that the increase of<br />technological parameters: time and temperature<br />of the process, as well as the concentration of<br />the osmotic solutions led to the intensified mass<br />transfer in the process and increased values of<br />process responses, in either co-counter or<br />current processes of osmotic solutions.<br />Based on obtained results mathematical models<br />of dependence of process responses from<br />applied technological parameters for co- and<br />counter-current processes of osmotic<br />dehydrations were developed. By the means of<br />&ldquo;Score&rdquo; analyses the values of technological<br />parameters which produced optimal efficiency<br />of the process were calculated.<br />In this research process energy balance was<br />investigated by comparison to the convective<br />drying, where the highest energy efficiency was<br />determined in the processes at the temperature<br />of 20&deg;C.<br />Characteristics of osmo-dehydrated pork meat<br />were also investigated, pointing at the<br />improvement of microbiological, chemical and<br />nutritive profile of the meat after the process, as<br />well as the change of color and texture, where<br />sugar beet molasses, as an osmotic solution, had<br />shown the best effects on changes of dehydrated<br />meat characteristics.<br />Based on all investigated effects of varied<br />parameters, the optimal process parameters can<br />be defined as: counter-current process, of 5<br />hours duration, at 20&deg;C, in molasses as an<br />osmotic solution. Process like that leads to the<br />total improvement of pork meat characteristics<br />introducing nutritive benefit from molasses<br />chemical composition into human nutrition.</p>
224

Superchilling of muscle food : Storage stability and quality aspects of salmon (Salmo salar), cod (Gadus morhua) and pork

Duun, Anne Sissel January 2008 (has links)
<p>Superchilling is a method that can be used to prolong the shelf life of foods by partial freezing. Knowledge of the effects of this method on both the shelf life and quality of foods is important in order to find optimal processing and storage conditions and is of great importance both for the industry and for the consumers. Different raw materials of muscle foods were studied with the purpose of creating a basis for further improvements of both the process and the storage conditions. Products from the commercially important species pork (both roasts and rib steaks), Atlantic salmon (both vacuum packed and wrapped fillets) and Atlantic cod (vacuum packed fillets) were chosen to represent different muscle foods.</p><p>Based on both sensory and microbial evaluations, the superchilled storage improved shelf life of pork roasts from 2 to 16 weeks, and shelf life might even be further prolonged if temperature is kept more constant. The H2S-producing bacteria in superchilled cod fillets did not exceed the limit of consumption during the whole storage period of six weeks, while the microbial shelf life of the ice chilled fillets was estimated to be 8 days after processing.</p><p>Quality changes have been studied with focus on biochemical and physiochemical properties. One of the major goals in meat and fish processing is the ability to retain water and it was observed that drip loss was lower in superchilled samples compared to traditionally chilled samples in all species studied. However, the subsequent liquid loss was higher both in pork roasts and in cod fillets.</p><p>The extractability of protein was used as a tool to monitor protein denaturation. It was found that myofibrillar proteins denatured more easily during superchilled than during traditionally chilled storage both in salmon and in cod fillets. This was confirmed by electrophoresis in salmon. The amount of free amino acids were higher in cod than in salmon and increased more during superchilled storage than during ice chilled storage indicating exoproteolytic activity during storage. Activities of cathepsins B and B + L in salmon fillets were relatively stable during the storage period in all storage groups, demonstrating that these enzymes are not deactivated at the selected storage temperatures and may therefore lead to softening during subsequent chilled storage.</p><p>In superchilled samples of all species studied, white spots emerged on the product surface. However, the appearance of spots did not correspond either to higher drip loss or to higher microbial growth on surface of these samples. On the contrary, the total plate counts of superchilled samples were lower than of the other storage groups. This observation also applied to iron agar counts on cod fillets. These findings are interpreted as a strong indication of that the spots most likely were not of microbial origin.</p><p>The optimal superchilling process and storage conditions remains to be found for the products studied. From the present results it is reasonable to suggest that optimal storage temperature for the vacuum packed salmon fillets is found between the superchilled temperatures in the present experiments. The quality both of the pork roasts and the cod fillets would probably benefit from a storage temperature slightly closer to 0 °C than those studied. It can also be assumed that the control of the superchilling process is more essential to cod than to salmon and pork. In addition, the properties of the raw material are crucial in order to obtain high quality of products after processing and storage.</p> / Paper I-III are reprinted with kind permission from Elsevier, sciencedirect.com
225

Superchilling of muscle food : Storage stability and quality aspects of salmon (Salmo salar), cod (Gadus morhua) and pork

Duun, Anne Sissel January 2008 (has links)
Superchilling is a method that can be used to prolong the shelf life of foods by partial freezing. Knowledge of the effects of this method on both the shelf life and quality of foods is important in order to find optimal processing and storage conditions and is of great importance both for the industry and for the consumers. Different raw materials of muscle foods were studied with the purpose of creating a basis for further improvements of both the process and the storage conditions. Products from the commercially important species pork (both roasts and rib steaks), Atlantic salmon (both vacuum packed and wrapped fillets) and Atlantic cod (vacuum packed fillets) were chosen to represent different muscle foods. Based on both sensory and microbial evaluations, the superchilled storage improved shelf life of pork roasts from 2 to 16 weeks, and shelf life might even be further prolonged if temperature is kept more constant. The H2S-producing bacteria in superchilled cod fillets did not exceed the limit of consumption during the whole storage period of six weeks, while the microbial shelf life of the ice chilled fillets was estimated to be 8 days after processing. Quality changes have been studied with focus on biochemical and physiochemical properties. One of the major goals in meat and fish processing is the ability to retain water and it was observed that drip loss was lower in superchilled samples compared to traditionally chilled samples in all species studied. However, the subsequent liquid loss was higher both in pork roasts and in cod fillets. The extractability of protein was used as a tool to monitor protein denaturation. It was found that myofibrillar proteins denatured more easily during superchilled than during traditionally chilled storage both in salmon and in cod fillets. This was confirmed by electrophoresis in salmon. The amount of free amino acids were higher in cod than in salmon and increased more during superchilled storage than during ice chilled storage indicating exoproteolytic activity during storage. Activities of cathepsins B and B + L in salmon fillets were relatively stable during the storage period in all storage groups, demonstrating that these enzymes are not deactivated at the selected storage temperatures and may therefore lead to softening during subsequent chilled storage. In superchilled samples of all species studied, white spots emerged on the product surface. However, the appearance of spots did not correspond either to higher drip loss or to higher microbial growth on surface of these samples. On the contrary, the total plate counts of superchilled samples were lower than of the other storage groups. This observation also applied to iron agar counts on cod fillets. These findings are interpreted as a strong indication of that the spots most likely were not of microbial origin. The optimal superchilling process and storage conditions remains to be found for the products studied. From the present results it is reasonable to suggest that optimal storage temperature for the vacuum packed salmon fillets is found between the superchilled temperatures in the present experiments. The quality both of the pork roasts and the cod fillets would probably benefit from a storage temperature slightly closer to 0 °C than those studied. It can also be assumed that the control of the superchilling process is more essential to cod than to salmon and pork. In addition, the properties of the raw material are crucial in order to obtain high quality of products after processing and storage. / Paper I-III are reprinted with kind permission from Elsevier, sciencedirect.com
226

The Japanese pork market facing international trade : introducing a spatial equilibrium model of international trade under consideration of a differential tariff system /

Bergen, Martina. January 2006 (has links) (PDF)
Univ., Diss.--Hohenheim, 2006.
227

Articulating the realm of the possible: two farm marketing boards and the legal administrative field

Jardine, David Neil 05 1900 (has links)
This thesis suggests that it is impossible to consider any administrative agency in the abstract without losing important elements of the nature of the legal environment within which the agency operates. There is a large gap between the theories of formal administrative law and the experience of practice in particular administrative settings. Drawing upon the work of sociologist Pierre Bourdieu, the thesis develops the concept of the legal administrative field as a means to approach this issue. The use of Bourdieu's concepts of field, habitus and capital help to articulate and give a theoretical structure to a process and series of practices that are otherwise hard to identify or study. Two Alberta farm marketing boards, and certain specific legal issues faced by each board, are examined in detail and analyzed in terms of the concept of the legal administrative field. It is shown that for each board, the realm of what was 'legally possible' shifted despite the fact that there were no changes in the formal administrative law and that legal practice in these fields involves far more than the application of the principles of formal administrative law. The intersection of the principles and habitus of formal administrative law, the structure provided by the legislative and regulatory framework, and the respective capital and habitus of all the individuals, agents and agencies within the field all interact and these complex interactions are what structure the legal administrative fields and shape the shifts which occur within them. In the struggles of interpretation which occur in these fields an attempt to make a clear demarcation between the practice of law by lawyers and the administration of the system by administrators is inadequate; it simplifies and renders invisible much of the complex series of interactions in which the legal practitioner is a participant and which create the field in which he or she practices. The conclusion is that the heuristic value of the legal administrative field in relation to the legal issues faced by the two marketing boards, and in relation to legal practice in the farm marketing area has been established and that this concept provides a useful perspective and a valuable supplement to a more traditional approach.
228

Cholesterolio kiekis skirtingų veislių kiaulių mėsoje / Cholesterol amount in the meat of different pig breeds

Puskunigytė, Jolanta 13 May 2005 (has links)
The aim of work – to determine the amount of cholesterol in the meat of different pig breeds. The task of research: 1. To analyse the literature about the effect of cholesterol on the human organism and also the peculiarity of concentration in the humans and animals. 2. To determine the amount of cholesterol in the Lithuanian White, Large White, Landrace and Yorkshire meat. Methodology. The samples were used from four different pig breeds: Lithuanian White, Large White, Landrace and Yorkshire of boars (castrates) and gilts. 20 samples were taken from each breed: 10 samples of bears and 10 samples of gilts. Pigs were fattened up at the State Pig Breeding Station in Baisiogala. The amount of cholesterol in pork was determined by using R–Biopharm GmbH company’s „Cholesterin–Testkontroll–Lösung“cholesterol assay control solution made in Germany and in spectrophometrical way, also. Conclusions: 1. The biggest amount of cholesterol was determined in the meat of Yorkshire pigs – 54.3 mg/100g P<0.01 and the smallest amount of cholesterol was found in the meat of Large White pigs–51.0 mg/100 g P<0.01. 2. Almost in all pig breeds the bigger amount of cholesterol was found in the meat of boars 0.1 – 3.7 mg/100 g or 0.2-7 % P>0.05, except Landrace pig breed. 3. According to the data of dispersive analysis breed had more influence P<0.05 than sex P>0.05 on the amount of cholesterol, but however it was dependent on the individual features of animal most.
229

Quebec hog producers' willingness to accept carbon credit revenue for adopting management practices that reduce greenhouse gas emissions

Guo, Yi, 1977- January 2007 (has links)
Canada's commitment to the Kyoto Protocol provides agricultural producers with an opportunity to supply carbon offset credits to a domestic carbon market and receive revenue from the sale of these credits. This study employed the multiple bounded discrete choice method to estimate Quebec hog producers' willingness to accept compensation to adopt two management practices that reduce carbon emissions; i.e. reduced protein feeding and adopting a manure storage cover. The average willingness to accept compensation for reduced protein feeding was $46.71 per tonne of CO2 equivalent and for the manure storage cover was $40.40 per tonne of CO2 equivalent. In addition, hog producers were asked what cost they would be willing to bear if they received $20 per animal unit in carbon offset credit revenue. The average cost they were willing to bear was $11.88. Key factors that influenced producers' decisions were identified. Results can be used to improve the institutional rules and public policy associated with developing a domestic carbon emission trading mechanism. Starting-point and sequencing bias were tested for with the convolution approach. Starting-point bias was found in all the hypothetical situations; while sequencing bias was not found.
230

The influence of feeding and aging on pork quality /

Tikk, Kaja, January 2007 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 5 uppsatser.

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