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Freeze-drying and solubility studies.Patel, Suresh Dahyabhai. January 1988 (has links)
The medium offering the greatest resistance to heat transfer from the freeze-drying shelf to the moving and subliming surface is the space between the flat shelf top and the concave vial bottom. The resistance to heat transfer can be greatly reduced by improving the thermal conductivity of the intervening space. Several heat transfer augmentation devices, including a multilayered corrugated aluminum quilt and a conformable fluid cushion device, which fill this gap are described. The devices are inexpensive and easy to use. Experimental data show that the resistance of the intervening space is reduced appreciably and the drying rate is greatly increased. The fluid cushion device is superior to the aluminum quilt as it reduces the consequences of spillage of solution and provides greater intervial uniformity among the same batch of vials. Drying times obtained in experiments with and without the fluid cushion device are compared here for different sizes and different types of vials. Product evaluation is conducted by measuring the reconstitution time and observing the product under a microscope. The solubilities of two univalent electrolytes, sodium chloride and potassium chloride, have been measured in eight cosolvent-water binary systems. The solubility of both the solutes has been found to be adequately described by the log-linear solubility equation, log S(m) = log S(w) + fσ. The rank order of the desolubilization slopes obtained for the electrolyte solutes is compared with the solubilization of nonelectrolyte solutes. These results indicate that a cosolvent which is most effective in solubilizing a nonelectrolyte is also most effective in desolubilizing an electrolyte. The solubility of oxacillin sodium in methanol-water mixtures has been determined at various temperatures ranging from +21 to -26 degrees centigrade. The data has been fitted to the log-linear relationship as proposed by Yalkowsky et. al. The heat of solution is determined using the van't Hoff equation and was found to be nearly constant at 1.2 Kcal/mole. There appears to be no dependency of the slope of the log S(m) vs. fraction cosolvent plot to the temperature. The data suggests that there is a polymorphic or amorphic transition of oxacillin at -14.5 degrees centigrade.
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The breakdown of ascorbic acid at different temperatures and amounts of dissolved oxygen in orange juiceOgsäter, Jens January 2014 (has links)
Vitamin C is an essential water soluble vitamin found mainly in fruits, vegetables and their derivatives. Orange juice is a popular thirst quencher and a convenient way to reach the daily recommended intake of vitamin C. The aim of this thesis was to determine how the vitamin C content in orange juice is affected by storage temperature and oxygen content in the product. Bottles of orange juice were stored at different temperatures. Regular orange juice was compared to juice where dissolved oxygen in product water had been decreased before mixing the juice. One other aim was to determine the efficiency of a stress test room where a higher temperature was supposed to simulate longer storage time. The study showed a larger non-linear loss of vitamin C over time in the bottles stored at the higher temperatures. The samples with less dissolved oxygen showed a higher vitamin C content after five and six months of storage in room temperature. For a storage time up to one week the loss of vitamin C in the stress test does not appear to be equal to the corresponding storage time in room temperature.KeywordsOrange juice, / Vitamin C är en livsnödvändig vattenlöslig vitamin som främst förekommer i grönsaker, frukter och produkter framställda från dessa. Apelsinjuice är en populär törstsläckare och ett enkelt sätt att få i sig sin dagliga dos C-vitamin. Syftet med denna rapport är att undersöka hur halten C-vitamin i apelsinjuice från Kiviks Musteri ändras beroende på lagringstemperatur och syrehalt i produktvatten. Apelsinjuice tillverkad från kranvatten jämfördes med juice tillverkad med vatten där syrehalten minskats genom kokning. Ett annat syfte var att fastställa effektiviteten för ett lagringsrum som simulerade en längre lagringsperiod genom att höja temperaturen. Resultaten visade att det var en större ickelinjär förlust av C-vitamin i flaskor som lagras vid en högre temperatur. Juiceflaskor med mindre mängd löst syre visade en lägre förlust av C-vitamin efter fem respektive sex månaders lagring i rumstemperatur. Förlusten av C-vitamin i juice lagrad en vecka i rummet med högre temperatur var ej den mängd som förutspåddes enligt företagets modell.
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The influence of different calcium levels, irrigation methods and storage temperatures on the yield, quality and growth potential of G0 mini-tubersDe Villiers, Andre Jaco 12 1900 (has links)
University of Stellenbosch. Faculty of Agrisciences. Dept. of Agronomy. / Thesis (MScAgric (Agronomy)--University of Stellenbosch, 2007. / Calcium (Ca) is an important plant nutrient with many functions, such as strengthening of cell walls and maintaining membrane stability and cell integrity. A greenhouse experiment was conducted using an aeroponic production system, to evaluate the influence of different Ca: K & Mg ratios (consisting of a control [100% Ca], and three treatments in which the Ca levels were changed to 33%, 66% and 133% of the control, while the K and Mg levels were adjusted to compensate for the change in Ca) and two different irrigation methods (irrigation on roots only, and irrigation on roots and stolons) on tuber yield and mineral concentration. The treatment that received the highest Ca: K & Mg ratio had significantly more larger tubers than the lowest Ca treatment, although there was no significant difference in total tuber number between treatments. The high Ca treatment also had a significantly higher Ca concentration in the skin than the low Ca treatment. The site of irrigation did not have a significant effect on the total tuber number per plant, or on the Ca content of the tubers that were produced.
The tubers produced in the first experiment were divided into two weight classes, and stored at three different temperatures. The percentage weight loss during storage was determined by weighing the tubers before, and again after storage. The firmness of the tubers was also measured after storage. Tubers were then stored in a dark room at room temperature to allow sprouts to develop. The sprouts of each tuber were counted and weighed. Weight loss was the lowest for tubers stored at 3oC. Firmness of the tubers increased as the Ca: K & Mg ratio of the nutrient solution used during production was increased. Number of sprouts was the highest for tubers stored at 6oC. Sprout number was also significantly higher for the larger tubers compared to the smaller ones. Total sprout weight was the highest for the tubers stored at 6oC, and was also the highest for the larger tubers.
After sprouts started to develop, the tubers were planted again in the greenhouse, in sawdust and irrigated with a complete Steiner nutrient solution at 1.5 mS cm-1. After these plants were harvested, the leaf area and dry weight of the leaves were determined. The first generation tubers were counted and weighed. The only factor that had a significant influence on the growth of the plants, was the size of the seed tubers that were used. The larger seed tubers produced plants that had significantly higher leaf areas, dry weight of leaves, as well as higher yields than that of the plants produced from the smaller seed tubers.
From the results of this study, it can be concluded that Ca has a definite positive effect on the quality of seed potatoes as well as the size of the tubers that are produced. This study also supported that seed tubers should be stored at low temperatures, around 3oC, to maintain the highest quality, while larger tubers proved to out-yield smaller ones.
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Arterial blood gas: an experiment to study the effects of temperature and time delays on the outcome of a blood gas resultBaker, Lynette Margaret 31 January 2008 (has links)
An arterialblood gas analysis which is conducted in critical care areas contributes to the assessment of a patient's ventilatory status and acid
-base balance.
The purpose of this research was to determine the relationship of time delays and temperature on the result of a blood gas analysis. The objective was to either accept or refute the null hypothesis, that there is no relationship between temperature and time delays and an arterial blood gas result
Fifteen subjects were randomly selected. The researcher drew three samples of arterial blood from each subject. Ethical principles were observed.
An inferential non-parametric statistic was used. The chi-squared test was used to test the hypothesis and the Friedman and the Wilcoxon signed ranks test were used to test the differences between the means.
The results revealed that there was a relationship between time delays, temperature and the arterial blood gas result. The null hypothesis was rejected. / Health Stusies / M.A. (Health Studies)
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Conservação de sementes de Talauma ovata St. Hil. / Talauma ovata St. Hil. seed conservationPupim, Túlio Lourenço 31 October 2008 (has links)
A pesquisa objetivou estudar a influência do grau de umidade da semente e da temperatura de armazenamento sobre a conservação das sementes de Talauma ovata. Para tanto, dois lotes de sementes com teores de água iniciais de 23,5% (lote 1) e 23,8% (lote 2) foram submetidos à secagem para a obtenção de sementes com os demais teores de água, 17,4%, 10,9% e 7,1% para o lote 1 e 15,8%, 13,1% e 10,0% para o lote 2. Em seguida, as sementes foram acondicionadas em sacos de polietileno e armazenadas sob temperaturas controladas de 15ºC e de 20ºC. As sementes foram armazenadas por 180 dias, lote 1, e por 60 dias, lote 2, e avaliadas mensalmente quanto ao teor de água, à emergência da plântula, ao índice de velocidade de emergência da plântula, à velocidade de emergência da plântula, ao comprimento da plântula e à massa da matéria seca da plântula; as sementes do lote 2 foram também avaliadas quanto à sanidade. O potencial fisiológico das sementes de Talauma ovata é favorecido pela secagam das sementes. A qualidade inicial das sementes de T. ovata influencia a longevidade das sementes. A secagem das sementes, para teores de água entre 10,9% e 13,1%, e o armazenamento das sementes a 15°C favorecem a conservação das sementes de T. ovata. / The research aimed to study the influence of the seed moisture content and storage temperature on Talauma ovata seed conservation. Thus, two seed lots with initial moisture content of 23.5% (lot 1) and 23.8% (lot 2) were dried and obtained tree moisture content levels in each lot, and the moisture contents were 17.4 %, 10.9% and 7.1% for lot 1 and 15.8%, 13.1% and 10.0% for lot 2. After obtaining the moisture content, seeds were conditioned in polyethylene bags and stored under controlled temperature at 15°C and 20°C. Seeds were stored for 180 days, lot 1, and 60 days, lot 2, and were monthly evaluated as for moisture content, sand seedling emergence, emergence index, seedling emergence speed, seedling length and seedling dry mass; seeds from lot 2 were also evaluated as health condition. Talauma ovata seeds has the phisiological potencial favored by drying seeds. T. ovata seed longevity has been influenced by initial quality. T. ovata seed conservation is favoured by seed with moisture content between 10,9% and 13,1% and storage temperature at 15°C.
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Conservação de sementes de Talauma ovata St. Hil. / Talauma ovata St. Hil. seed conservationTúlio Lourenço Pupim 31 October 2008 (has links)
A pesquisa objetivou estudar a influência do grau de umidade da semente e da temperatura de armazenamento sobre a conservação das sementes de Talauma ovata. Para tanto, dois lotes de sementes com teores de água iniciais de 23,5% (lote 1) e 23,8% (lote 2) foram submetidos à secagem para a obtenção de sementes com os demais teores de água, 17,4%, 10,9% e 7,1% para o lote 1 e 15,8%, 13,1% e 10,0% para o lote 2. Em seguida, as sementes foram acondicionadas em sacos de polietileno e armazenadas sob temperaturas controladas de 15ºC e de 20ºC. As sementes foram armazenadas por 180 dias, lote 1, e por 60 dias, lote 2, e avaliadas mensalmente quanto ao teor de água, à emergência da plântula, ao índice de velocidade de emergência da plântula, à velocidade de emergência da plântula, ao comprimento da plântula e à massa da matéria seca da plântula; as sementes do lote 2 foram também avaliadas quanto à sanidade. O potencial fisiológico das sementes de Talauma ovata é favorecido pela secagam das sementes. A qualidade inicial das sementes de T. ovata influencia a longevidade das sementes. A secagem das sementes, para teores de água entre 10,9% e 13,1%, e o armazenamento das sementes a 15°C favorecem a conservação das sementes de T. ovata. / The research aimed to study the influence of the seed moisture content and storage temperature on Talauma ovata seed conservation. Thus, two seed lots with initial moisture content of 23.5% (lot 1) and 23.8% (lot 2) were dried and obtained tree moisture content levels in each lot, and the moisture contents were 17.4 %, 10.9% and 7.1% for lot 1 and 15.8%, 13.1% and 10.0% for lot 2. After obtaining the moisture content, seeds were conditioned in polyethylene bags and stored under controlled temperature at 15°C and 20°C. Seeds were stored for 180 days, lot 1, and 60 days, lot 2, and were monthly evaluated as for moisture content, sand seedling emergence, emergence index, seedling emergence speed, seedling length and seedling dry mass; seeds from lot 2 were also evaluated as health condition. Talauma ovata seeds has the phisiological potencial favored by drying seeds. T. ovata seed longevity has been influenced by initial quality. T. ovata seed conservation is favoured by seed with moisture content between 10,9% and 13,1% and storage temperature at 15°C.
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N?veis de ?cidos graxos e qualidade de ovos comerciais convencionais e enriquecidos com ?mega-3. / Fatty acid levels and quality of conventional and enriched omega-3 eggs.Cedro, Thaiz Marinho Magalh?es 29 August 2008 (has links)
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Previous issue date: 2008-08-29 / 1160 eggs were utilized in four experiments were conducted in Eggs Analyses Laboratory of
the Institute of Animal Science of the Rural Federal University of Rio de Janeiro (UFRRJ)
using commercial eggs produced by two groups of laying hens line Isa Brown with 33 weekold.
In group 1, the birds were fed throughout their productive life with a basic diet of corn
and soybean meal, while in group 2, since 22? weeks-old of the hens, was added to the basic
diet 1.5% of marine algae substrate and 1.8% fish oil (production of enriched ω-3 eggs). In
experiment 1, whose aim was to evaluate the internal and external quality of conventional and
enriched ω-3 eggs stored at different temperatures, it was found that both types of eggs
studied had similar characteristics of internal and external quality. Eggs stored for 21 days at
25?C had lower averages for Haugh unit and yolk index and higher averages of albumen pH
and yolk pH when compared to other treatments related to temperature and period of storage.
There were no significant differences in egg shell thickness, shell weight and shell percentage
between the two types of eggs stored for 21 days, regardless of the temperature of storage. In
experiment 2 was assessed the influence of the season on the quality of enriched ω-3 eggs
stored in refrigerated environment. In this second issue was verify that the eggs collected in
the summer showed eggs weight and internal and external quality aspects lower than those
collected in winter. In this second issue was verify that the eggs collected in the summer
showed eggs weight and internal and external quality aspects lower than those collected in
winter. In this second issue was verify that the eggs collected in the summer showed eggs
weight and internal and external quality aspects lower than those collected in winter. The
storage affected negatively the eggs weight, Haugh unit and yolk index, but there was no
effect on the shell thickness. In experiment 3 was compared the fatty acids levels and
relationships in conventional and enriched ω-3 eggs. The enriched ω-3 eggs showed total
levels of ω-3 polyunsaturated (1839 mg/100g of yolk) and monounsaturated fatty acids
(10,744 mg/100g of yolk) higher than those of conventional eggs (927 and 7997 mg/100g of
yolk, respectively). Relations between polyunsaturated/saturated fatty acids (P/S) and between
ω-6/ω-3 of enriched eggs were close to the ideal estimated for human consumption (1.10 and
3.00, respectively). The conventional eggs had total levels of saturated (8740 mg/100g of
yolk) and ω-6 polyunsaturated fatty acids (9600 mg/100g of yolk) significantly higher than
the enriched ω-3 eggs (6640 and 5510 mg/100g of yolk, respectively). In Experiment 4, three
people individually assessed the intensity of yolk pigmentation with a color range. It was
found that conventional eggs had the yolk less pigmented enriched ω-3 ones. The storage at
different temperatures caused the appearance of dark spots in the egg yolks enriched. Based
on the results obtained in experimental conditions used it was found that enriched ω-3 eggs
showed high levels of ω-3 polyunsaturated fatty acids, appropriate balance of the relations
between P/S and between ω-6/ω-3 and good characteristics of internal and external quality,
thus those eggs can be considered an excellent alternative food for those consumers concerned
about eating healthy diets. / Foram utilizados 1160 ovos comerciais em quatro experimentos realizados no Laborat?rio de
An?lises de Ovos do Instituto de Zootecnia da Universidade Federal Rural do Rio de Janeiro
(UFRRJ) produzidos por dois grupos de poedeiras da linhagem Isa Brown com 33 semanas de
idade. No grupo 1, as aves foram alimentadas durante toda vida produtiva com ra??o a base
de milho e farelo de soja (produ??o de ovos convencionais), enquanto que no grupo 2, ? partir
da 22? semana de idade das aves, foi acrescentado a ra??o b?sica 1,5% de substrato de algas
marinhas e 1,8% de ?leo de peixe (produ??o de ovos enriquecidos com ω-3). No experimento
1, cujo objetivo foi avaliar a qualidade interna e externa de ovos comerciais convencionais e
enriquecidos com ω-3 armazenados em diferentes temperaturas, foi verificado que os dois
tipos de ovos estudados apresentaram caracter?sticas de qualidade interna e externa
semelhantes. Os ovos armazenados por vinte e um dias a 25?C apresentaram menores m?dias
para unidade Haugh e ?ndice de gema e maiores para pH do alb?men e da gema quando
comparado aos demais tratamentos relacionados a temperatura e per?odo de armazenamento.
N?o foram observadas diferen?as significativas para espessura, percentual e peso da casca
entre os dois tipos de ovos estocados por vinte e um dias, independentemente da temperatura
de armazenamento. No experimento 2 foi avaliada a influ?ncia da esta??o do ano sobre a
qualidade de ovos enriquecidos com ω-3 armazenados em ambiente refrigerado. Neste
segundo ensaio foi observado que os ovos coletados no ver?o apresentaram peso, qualidade
interna e externa inferior ao daqueles coletados no inverno. Com rela??o ao armazenamento,
foi verificado efeito negativo sobre o peso, unidade Haugh e ?ndice de gema, mas n?o houve
efeito sobre a espessura da casca destes ovos. No experimento 3, comparou-se os n?veis de
?cidos graxos e suas rela??es em ovos comerciais convencionais e enriquecidos com ω-3 e foi
verificado que os ovos enriquecidos com ω-3 apresentaram teores totais de ?cidos graxos
(AG) poliinsaturados da s?rie ω-3 (1839 mg/100g de gema) e de AG monoinsaturados (10744
mg/100g de gema) significativamente superiores aos dos ovos convencionais (927 e 7997
mg/100g de gema, respectivamente). As rela??es entre os ?cidos graxos
poliinsaturados/saturados (P/S) e entre ω-6/ω-3 dos ovos enriquecidos foram pr?ximas ao
ideal estimado para o consumo humano (1,10 e 3,00; respectivamente). Os ovos
convencionais apresentaram teores totais de AG saturados (8740 mg/100g de gema) e de AG
poliinsaturados da s?rie ω-6 (9600 mg/100g de gema) significativamente superiores aos dos
ovos enriquecidos ω-3 (6640 e 5510 mg/100g de gema, respectivamente). No experimento 4,
tr?s pessoas individualmente avaliaram a intensidade de pigmenta??o da gema com o aux?lio
de um leque colorim?trico. Foi verificado que os ovos convencionais apresentaram gema
menos pigmentada que os ovos enriquecidos com ω-3. O armazenamento em diferentes
temperaturas provocou o aparecimento de manchas escuras nas gemas dos ovos enriquecidos.
Com base nos resultados obtidos nas condi??es experimentais utilizadas concluiu-se que os
ovos enriquecidos com ω-3 apresentaram elevados n?veis de AG poliinsaturados da s?rie ω-3,
balan?o adequado das rela??es entre ω-6/ω-3 e P/S e boas caracter?sticas de qualidade interna
e externa, sendo desta forma, considerados uma excelente alternativa de alimento para aqueles
consumidores preocupados em ingerir dietas mais saud?veis.
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Arterial blood gas: an experiment to study the effects of temperature and time delays on the outcome of a blood gas resultBaker, Lynette Margaret 31 January 2008 (has links)
An arterialblood gas analysis which is conducted in critical care areas contributes to the assessment of a patient's ventilatory status and acid
-base balance.
The purpose of this research was to determine the relationship of time delays and temperature on the result of a blood gas analysis. The objective was to either accept or refute the null hypothesis, that there is no relationship between temperature and time delays and an arterial blood gas result
Fifteen subjects were randomly selected. The researcher drew three samples of arterial blood from each subject. Ethical principles were observed.
An inferential non-parametric statistic was used. The chi-squared test was used to test the hypothesis and the Friedman and the Wilcoxon signed ranks test were used to test the differences between the means.
The results revealed that there was a relationship between time delays, temperature and the arterial blood gas result. The null hypothesis was rejected. / Health Stusies / M.A. (Health Studies)
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Avaliação da temperatura de armazenamento e uso de antimicrobianos na qualidade de doses seminais de suínos / Evaluation of storage temperature and use of antibiotics in boar semen dose qualityMenezes, Tila de Alcantara January 2018 (has links)
A bacteriospermia pode prejudicar a qualidade das doses de sêmen suíno. Desta forma, a adição de antimicrobianos (ATM) aos diluentes de sêmen é imprescindível para a manutenção da qualidade das doses inseminantes. Contudo, a crescente ocorrência de resistência bacteriana tem impulsionado a redução do uso de ATM na suinocultura. Nesse sentido, o armazenamento das doses inseminantes em baixas temperaturas pode ser uma alternativa para a remoção dos ATM dos diluentes comerciais. Sendo assim, no presente estudo, foram realizados dois experimentos para avaliar a qualidade espermática e a contagem de unidades formadoras de colônias (UFC/mL) de doses de sêmen suíno submetidas a baixas temperaturas de armazenamento, na ausência ou presença de ATM. No experimento 1, as motilidades (total e progressiva) das doses com ATM foram maiores conforme aumentou a temperatura de armazenamento (P<0,01). Nas doses sem ATM, as motilidades foram inferiores nas mantidas a 5 °C do que nas demais (P<0,05). O número de UFC/mL foi menor nas doses sem ATM mantidas a 5 e 10 °C do que a 17 °C (P<0,05), mas não houve diferença entre as temperaturas de armazenamento nas doses com ATM (P>0,05). As integridades de acrossoma e de membrana plasmática não foram afetadas (P>0,05) pelo uso de ATM, mas foram influenciadas pela temperatura de armazenamento (P<0,0001) No experimento 2, os machos foram categorizados em BONS e RUINS de acordo com a motilidade progressiva das doses com ATM armazenadas a 5 °C nas 120 h, sendo investigado o efeito dessas categorias sobre as variáveis estudadas. A motilidade total das doses armazenadas a 17 °C foi superior à das mantidas a 5 °C diluídas sem ATM (P<0,05). Os percentuais de motilidade progressiva e de acrossomas normais foram superiores nas doses mantidas a 17 °C do que nas mantidas a 5 °C, com ou sem ATM (P<0,05). O número de UFC/ml foi maior nas doses diluídas sem ATM do que nas demais (P<0,05). Após a categorização dos machos, as motilidades (total e progressiva) foram maiores nos machos BONS do que nos RUINS (P<0,05), sem diferença significativa (P>0,05) nas integridades (acrossomal e de membrana plasmática). Apesar de a qualidade espermática ter sido afetada negativamente pelas baixas temperaturas, o armazenamento das doses de sêmen suíno a 5 °C é possível, uma vez que foi mantida a viabilidade espermática in vitro, por até 5 dias, acima do nível mínimo considerado adequado para a inseminação artificial. Contudo, o uso de doses sem antimicrobianos ainda precisa de otimização, posto que que as baixas temperaturas de armazenamento reduzem, mas não inibem por completo o crescimento bacteriano. / Bacteriospermia can impair boar semen dose quality. Thus, the addition of antibiotics (ATB) is indispensable for maintaining semen doses quality. Nevertheless, growing bacterial resistance occurrence have had driven to a reduction in use of ATB in pig industry. In this sense, storage of semen doses at low temperature may be an alternative to removal ATB of commercial semen extenders. Therefore, the aim of the present study was to assess sperm quality and number of colony-forming units (CFU mL-1) in boar semen doses stored at low storage temperatures with or without ATB, in two experiments. In experiment 1, in semen doses with ATB, total and progressive motility increased as the storage temperature increased (P<0.01). In semen doses without ATB, total and progressive motility were observed to be lower when stored at 5 °C than at 10 and 17 °C (P<0.05). The number of CFU mL-1 was lower in semen doses without ATB stored at 5 and 10 °C than at 17 °C (P<0.05), but there was no difference among storage temperatures in doses with ATB (P>0.05). Acrosome and sperm membrane integrity were not influenced (P>0.05) by using ATB, but they were influenced by storage temperature (P<0,0001) In experiment 2, boars were grouped in GOOD and POOR according to progressive motility in doses stored for up to 120 h at 5 °C. So, the effect of this classification on assessed variables, was investigated. Total motility was higher in doses stored at 17 °C than in doses without ATB stored at 5 °C (P<0.05). The percentages of progressive motility and normal acrosomes were higher in doses stored at 17 °C than in doses stored at 5 °C, with or without ATB (P<0.05). The number of CFU mL-1 was higher in doses without ATB than in remaining ones (P<0.05). Total and progressive motility were observed to be higher in GOOD than in POOR boars (P<0.05). There was no difference between groups of boars in acrosome and membrane integrity (P>0.05). Despite sperm quality was negatively affected by low temperatures, the storage of boar semen doses at 5 °C is possible, since sperm viability in vitro was maintained for up to 5 days, fulfilling the requirements of semen quality to be used in artificial insemination. Nevertheless, the use of semen doses without ATB will need optimization, since low storage temperatures decreased bacterial growth, but not completely inhibit it.
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Effects of Potassium Lactate, Encapsulated Citric Acid and Storage Temperature on Microbial Growth and Shelf Life of Pork SticksSu, Yen-Kan 01 May 1992 (has links)
A new product, pork sticks, was developed. Optimum shelf life and safety were major concerns associated with this product. Potassium lactate (3%) or citric acid (0.5%, 0.56%, 0.60% or 0.66%) was added to pork sticks to determine their effects on microbial growth, sensory evaluation, and shelf life when stored frozen (-20°C), refrigerated (2°C), or at room temperature (22°C). Two raw materials, pork blade meat (shoulder meat; 91% lean, 9% fat) and regular 80:20 pork trim (80% lean, 20% fat) were used. The consumer panel preferred lean pork sticks made from blade meat over high-fat pork sticks made from regular 80:20 pork trim, regardless of the addition of potassium lactate (3%) or citric acid (0.5%). Pork sticks vacuum-packaged and held at 2°C or -20°C did not develop bacterial spoilage during six months storage. However, bacterial spoilage and oxidative rancidity occurred in the unpackaged control samples held at 22°C for one month. Incorporation of potassium lactate (3%) or citric acid (0.5%) decreased the color uniformity and red color intensity and increased the brown color intensity of the pork sticks made from blade meat. Vacuum-packaged pork sticks with added citric acid (0.56%, 0.60% and 0.66%) stored at 22°C did not develop bacterial spoilage, but discoloration occurred after one month storage.
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