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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.
131

Desenvolvimento do produto de conveniência Quenelle de tilápia (Oreochromis niloticus) / Product development of convenience quenelle tilapia (Oreochromis niloticus)

Maria Fernanda Calil Angelini 17 November 2010 (has links)
Para o desenvolvimento de um novo produto, busca-se atender a necessidade da indústria, do mercado e do consumidor, nos parâmetros qualidade, conveniência e com valor nutritivo que remeta à boa saúde. Com o objetivo de desenvolver o coproduto Quenelle de tilápia iniciou-se a etapa criativa de elaboração e a seguir, estabeleceu-se o processo do estudo de vida útil, a fim de definir a validade do produto, com base nos parâmetros físico-químico, microbiológico e sensorial. Na primeira etapa, 11 formulações foram testadas e a partir da avaliação destas, outras 4 formulações foram desenvolvidas e avaliadas através de análise sensorial de preferência por ordenação, resultando na formulação eleita composta dos seguintes ingredientes: Minced, gordura vegetal, cebola desidratada, proteína isolada de soja, tempero Hondashi, salsa desidratada, urucum e sal. O teste de vida útil foi realizado no período de 120 dias, sendo as análises físico-químicas, microbiológicas e sensoriais realizadas a cada 30 dias. O produto Quenelle contém, em média, 69,63 g/100g de umidade, 2,46 g/100g de cinza, 8,51 g/100g de lipídeos,15,18 g/100g de proteína e 4,23 g/100g de carboidrato, apresentando valor de TBARS de 1,12 mg malonaldeído/kg e pH de 6,5. Quanto às análises microbiológicas os valores foram os seguintes: para psicrotróficos 3,24 log UFC/g; coliformes termotolerantes, <3,0 NMP/g; coliformes totais, 3,6 NMP/g; Staphylococcus aureus, <10 NMP/g e ausência de Salmonella em 25/g. O produto foi embalado em dois tipos de embalagem, pouche de polietileno com zíper (QA) e embalagem de polietileno complementada com caixa de cartão parafinado (QB). A rotulagem, para a porção de 40g de Quenelle, mostrou os seguintes valores: 59 kcal, 2,1g de carboidrato, 5,64g de proteína, 2,84g de gorduras totais, 1,53g de gordura monoinsaturada, 0,64g de poliinsaturada, 0,04g de ômega 3 e 0,56g de ômega 6, 1,06g de gordura saturada, 0,39 de gordura trans, 0,63 mg de ferro, 271 mg de sódio, 10 UI de vitamina A, 3,03 mcg de retinol. A análise sensorial foi realizada através de um teste de avaliação de atributos, aparência (úmida, homogênea, impressão global), aroma (característico de peixe, característico do produto), textura (maciez, suculência, elasticidade), gosto (sal) e sabor (característico de peixe, condimento, off flavor de barro, off flavor de geladeira). Os valores médios dos atributos avaliados de Quenelles de tilápia em diferentes embalagens (QA e QB), durante o armazenamento, não apresentaram diferença significativa (p>0,05), bem como a interação tratamento versus provador. Quando se avaliou as médias dos atributos sensoriais nos dias de armazenamento e para as diferentes embalagens, pôde-se notar que houve diferença significativa (p<0,05) para todos os atributos, com exceção da maciez. Os provadores tiveram procedimento considerado significativo, para alguns atributos, como aparência úmida, aroma característico de peixe e do produto, e sabor de barro e de geladeira; com isso, algumas interações dias versus provador foram significativas, tais como aparência úmida, aroma característico de peixe e do produto, maciez, suculência, elasticidade, sabor característico de peixe, de condimento, de barro e de geladeira, e gosto de sal, exceto a aparência homogênea. / To develop a new product, we seek to meet the needs of industry, market and consumer. In questions, quality and convenience, offering food with nutritional value referring to good health. The objective was developing the co-product Quenelle of tilapia and began the creative phase of development. Created formulation, settled the case study of life in order to determine the shelf life of the product, based on physicalchemical, microbiological and sensory parameters. In the first stage, 11 formulations were tested by sensory analysis and preference ordering, resulting in the final formulation containing the following ingredients: minced, vegetable fat, dehydrated onion, soy protein isolate, Hondashi seasoning, salt and annatto. The shelf life test was carried out in 120 days, and the physical-chemical, microbiological and sensory testing performed every 30 days. The results were obtained for moisture 69.63 g.100g-1; ash 2.46 g.100g-1; fat, 8.51 g.100g-1, protein 15.18 g.100g-1and, 4.23 g.100g-1 carbohydrate. The value of TBA was 0.45 mg malonaldehyde / kg and pH was 6.5. As microbiological analysis the values were to psicotrophic 3.24 log CFU.g-1 / g, fecal coliform, <3.0 MPN.g- 1, total coliforms, 3.6 MPN.g-1, Staphylococcus aureus, <10 MPN.g-1and absence of Salmonella 25 / g. The product was packaged in two types of packaging, polyethylene pouch with zipper (QA) and polyethylene packaging more waxed cardboard box (QB). The label for the serving of 40g quenelle was: 59 kcal, 2.1 g of carbohydrate, 5.64 g of protein, 2.84 g of total fat, 1.53 g of monounsaturated fat, 0.64 g of polyunsaturated, 0.04 g of omega 3 and 0.56 g of omega 6, 1.06 g of saturated fat, 0.39g trans fat, 0.63 mg of iron, 271 mg of sodium, 10 IU of vitamin A, 3.03 mcg of retinol. Sensory analysis was performed using a test evaluation of attributes with six trained testers, where the samples showed no significant difference (p> 0.05) during storage. Sensory analysis was performed by an evaluation test attributes of appearance (moisture, homogeneous, general impression), aroma (fish characteristic, typical of product), texture (tenderness, juiciness, elasticity), taste (salt), flavor (fish characteristic, spices, mud off flavor, storage off flavor) with six trained testers. The average values of the attributes evaluated Quenelles tilapia in different packages (QA and QB), during storage, showed no significant difference (p > 0.05). The taster versus treatment interaction was not significant (p> 0.05). When assessing the means of sensory attributes in the days of storage, also considering the average values for all days (0, 30, 60, 90 and 120) of storage, besides the different packages (QA and QB), it was noted that significant differences (p <0.05) for all attributes except tenderness. Tasters procedure were considered significant (p <0.05) for some attributes, such as moisture appearance, aroma of fish and product, and taste of mud and storage; with it, some days versus tester interactions were significant (p <0.05), such moisture, aroma of fish and product, tenderness, juiciness, elasticity, flavor of fish, spices, mud, storage and salt, except the appearance homogeneous. The treatments interaction versus days of storage, just taste of storage showed significant difference (p <0.05).
132

Efeito do processamento m?nimo sobre a qualidade de cultivares de uvas de mesa / Minimal processing effect on the quality of table grape cultivars

Pereira, Bruna Rodrigues 29 September 2015 (has links)
Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-10-18T10:52:37Z No. of bitstreams: 1 2015 - Bruna Rodrigues Pereira.pdf: 2671756 bytes, checksum: b38e36947fda465d9d78272a81b2e947 (MD5) / Made available in DSpace on 2017-10-18T10:52:37Z (GMT). No. of bitstreams: 1 2015 - Bruna Rodrigues Pereira.pdf: 2671756 bytes, checksum: b38e36947fda465d9d78272a81b2e947 (MD5) Previous issue date: 2015-09-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / This study aimed to evaluate the quality of 'Sweet Celebration' and 'Sweet Globe' grapes, subjected to minimally processing, as well as the effectiveness of three rinsing solutions (water, sodium metabisulfite and chlorine) and pedicel cut intensity (with and without pedicel), in the conservation of these fruits during 12 days refrigerated storage to temperature at 8 ? C . The experiments were performed at Embrapa Agroind?stria de alimentos. For both experiments were applied rinse solutions, with water, sodium metabisulfite (20 mg. L-1) and chlorine (8 mg. L-1), that characterized the treatments, during the rinse step of minimally processing grapes, it being used two pedicel cut intensities:full cut and maintenance of a little fragment about 0,5 cm. Quality analyzes were performed at 0, 3, 6, 9, and 12 days of storage, and it was determined fresh weight loss cumulative , fruit firmness, color analysis, acidity, pH, total soluble solids, SST/ATT rate , sugars (sucrose , fructose and glucose) and enzymatic activity of pectinametilesterase for both cultivars. For Sweet Celebration grapes were also carried out the percentage fruit loss (9th and 12th day of storage) and anthocyanins. In 'Sweet Globe' grapes were realized total carotenoids, chlorophylls (a, b and total) and microbiological analyses. To the cultivate Sweet Celebration was possible identify berries out of commercial standard in the 9? day of storage. In the fresh weight loss cumulative, berries without pedicel had higher loss in the rinse with water from the 6th day of storage. For berries with pedicel the rinse with chlorine had the lowest fresh weight loss cumulative up 9th day of storage. For the firmness , berries without pedicel (4.44 N) had lower firmness compared to berries with pedicel (5.04 N), there wasn't significant difference between the rinsing solutions (p> 0.05). To cultivate Sweet Globe, berries with pedicel and rinsed with water had higher fresh weight loss cumulative from the 9th day of storage. In the berries without pedicel the rinse with water led to lower fresh weight loss cumulative from the 6th day of storage. There was no difference between the isolated factors rinse solutions and pedicel cut intensit to the firmness analysis. All rinse solutions were efficient in the microbiological analysis, so the minimally processed Sweet Globe grapes were in the standard established by law for human consumption / O presente trabalho objetivou avaliar a qualidade de uvas ?Sweet Celebration? e ?Sweet Globe?, submetidas ao processamento m?nimo, assim como a efetividade de tr?s solu??es enxaguantes (?gua, metabissulfito de s?dio e cloro) e da intensidade de corte do pedicelo (com e sem pedicelo), na conserva??o desses frutos, durante 12 dias de armazenamento refrigerado a 8?C. Os experimentos foram realizados na Embrapa agroind?stria de alimentos. Para ambos experimentos, foram aplicadas solu??es de enx?gue, com ?gua, metabissulfito de s?dio (20 mg. L-1) e cloro (8 mg. L-1), que caracterizaram os tratamentos, durante a etapa de enx?gue do processamento m?nimo das uvas, sendo adotadas duas intensidades de corte do pedicelo: retirada total do mesmo e manuten??o de um pequeno fragmento com aproximadamente 0,5 cm. Foram realizadas an?lises de qualidade nos 0, 3, 6, 9, e 12 dias de armazenamento, sendo determinadas a perda acumulada de massa fresca, firmeza dos frutos, an?lise de cor, acidez, pH, s?lidos sol?veis totais, rela??o SST/ATT, a??cares (sacarose, frutose e glicose) e atividade enzim?tica da pectinametilesterase para as duas cultivares. Para as uvas Sweet Celebration, foram tamb?m realizadas a porcentagem de perda de frutos (9? e 12? dia de armazenamento) e antocianinas totais. Para as uvas ?Sweet Globe?, foram realizadas as an?lises de caroten?ides totais, clorofilas (a, b e total) e an?lise microbiol?gica. Para a cultivar Sweet Celebration, foi poss?vel detectar bagas fora de padr?o comercial no 9?dia de armazenamento. Na perda acumulada de massa fresca, bagas sem pedicelo apresentaram maior perda no enx?gue com ?gua a partir do 6? dia de armazenamento. Para bagas com pedicelo o enx?gue com cloro apresentou a menor perda acumulada de massa fresca at? o 9? dia de armazenamento. Para a firmeza das bagas, bagas sem pedicelo (4,44 N) apresentaram menor firmeza, quando comparadas ?s bagas com pedicelo (5,04 N), n?o havendo diferen?a significativa entre as solu??es de enx?gue (p> 0,05). Para a cultivar Sweet Globe, bagas com pedicelo e enxaguadas com ?gua, apresentaram maior perda acumulada de massa fresca , a partir do 9? dia de armazenamento. Para bagas sem pedicelo o enx?gue com ?gua levou a menor perda acumulada de massa fresca a partir do 6? dia de armazenamento. N?o houve diferen?a entre os fatores isolados solu??es de enx?gue e intensidade de corte do pedicelo para a an?lise de firmeza. Todas as solu??es de enx?gue foram eficientes do ponto de vista microbiol?gico, estando as uvas Sweet Globe minimamente processadas dentro do padr?o estabelecido pela legisla??o para consumo humano
133

Avaliação das barreiras aplicadas às linguiças cozidas e defumadas como investigação das causas de sua deterioração / Evaluation of the hurdle applied to cooked and smoked sausages as an investigation of the causes of their deterioration

Chinait, Tatiana Maria Nogueira 28 June 2019 (has links)
Linguiças cozidas defumadas armazenadas a temperatura ambiente, é um produto tipicamente brasileiro, no qual são empregadas algumas barreiras para a extensão do shelf life: cozimento, defumação e embalagem à vácuo. Estudos de durabilidade comprovaram que muitas não atendem ao shelf life esperado. Na empresa estudada, somente 23% dos lotes das linguiças em estudo atenderam a 90 dias de armazenamento desejados para a indústria de alimentos e 17% dos lotes não chegaram à 45 dias. Foram realizadas avaliações microbiológicas antes do cozimento (média de 5,03 log UFC/g), após cozimento (média de 1,56 log UFC/g) e após resfriamento (média 1,54 log UFC/g) para os gomos com calibre de 40-44mm; comprimento 23-26cm; com peso variando de 260-300 gramas onde foram submetidos ao processo de cozimento e defumação por, no mínimo, 5 horas, atendendo no mínimo 71,1°C no centro térmico do gomo. Os parâmetros físico-químicos também foram avaliados e atendem a legislação, com valores de aw 0,938 e pH 6,33, favoráveis ao desenvolvimento microbiológico. Também foram realizadas análises sensoriais para avaliação dos atributos sensoriais ao longo do armazenamento a temperatura ambiente. / Smoked sausages stored at room temperature, is a typical Brazilian product, in which some hurdles are used to extend shelf life: cooking, smoking and vacuum packing. Durability studies have proven that many do not achieve the expected shelf life. In the studied company, only 23% of the lots of the sausages under study attended the 90 days of storage desired for the food industry and 17% of the lots did not reach 45 days. Microbiological evaluations were performed before cooking (average of 5.03 log CFU/g) after cooking (mean of 1.56 log CFU/g) and after cooling (mean 1.54 log CFU/g) for the caliber 40-44mm; length 23-26cm; with weight varying from 260-300 grams where they were submitted to the cooking and smoking process for at least 5 hours, attending at least 71.1°C in the thermal center of the oven. The physico-chemical parameters were also evaluated and comply with the legislation, with values of aw 0.938 and pH 6.33, favorable to the microbiological development. Sensory analyzes were also performed to evaluate the sensory attributes along the storage at room temperature.
134

Microbiological and Sensory Effects of Milk Processed for Extended Shelf Life and the Development of Rapid Methods to Quantitate Spores and Lipase Activity

Blake, Michael R. 01 May 1996 (has links)
The initial aim of this work was to evaluate processing conditions for extended shelf life (ESL) milk to have a shelf life at refrigeration temperature of 60 d. Milk was processed on a pilot-scale ultra-high-temperature processing plant and evaluated for microbial and sensory quality over 60 d at 7°C storage. Results of this study showed that lower process temperatures were preferable to minimize cooked flavors and that the minimum safe processing temperature was 134°C for 4 s as determined by the destruction of bacterial spores in the processed milk. Consumer preference panel results indicated that consumers preferred milk processed at 134°C for 4 s (those recommended in this study for ESL processing) to commercial UHT milk although there was a slight preference for pasteurized milk. The critical sensory characteristic of the processed milk was a cooked flavor, which decreased with lower processing temperature and shorter storage time; however, a significant increase in flavors that could be associated with lipolytic activity was also noted. This study highlighted deficiencies in existing methods for determining heat-stable bacterial products in thermal-processed foods. No rapid, sensitive assay for detection of heat-stable spores or lipases in milk exists. If such assays were available, it would allow processors to determine Lipase activity and bacterial spore counts before processing and direct raw milk with low spore counts and low lipolytic activity into long-shelf-life products. To this end, assays to rapidly quantitate spores and lipolytic activity in milk were developed. The lipase assay relies on the hydrolysis of p-nitrophenyl caprylate liberating a yellow color that is detected using reflectance colorimetry. The assay is sensitive to 5 mUnits/ml and is linearly correlated to spectrophotometry (r2 = 0.93) and release of titratable free fatty acids (r2 = 0.92 to 0.97). An immunocapture, enzyme-linked immunoassay coupled with a fluorescent detection system was developed for and resulted in a prototype spore assay using Bacillus stearothermophilus spores. This organism was selected because it is extremely heat resistant, is commonly found in milk, and is associated with spoilage of milk and milk products. The assay was able to quantitate spores down to 103 cfu/ml in milk and other products in about 1.5 h. Other detection limits could be set if needed.
135

藥品安定性儲存條件及有效期限之研究

吳林明 Unknown Date (has links)
藥品安定性試驗的目的乃在於確保該藥品具有優良藥品之特性,以保障消費者之權益。而藥品安定性試驗的品質良窳實取決於當地政府機關對其試驗之要求準則而定。近年來,我國不斷的在藥品安定性試驗方面進行研究和推擴,以提升國內市面上藥品之品質。本論文主要探討兩個主題:一是有關台灣在進行藥品安定性研究時,所規定藥品存放環境的溫度及溼度,以擬定出適合台灣環境之藥品儲存的溫溼度存放標準。二是針對藥品長期安定性試驗有效期限估算之軟體開發,使藥廠對藥品安定性試驗有效期限估算之研究分析更加便利。
136

Application of high pressure processing for extending the shelf-life of fresh lactic curd cheese

Daryaei, Hossein, s3088498@student.rmit.edu.au January 2008 (has links)
Outgrowth of spoilage yeasts and moulds and post-processing acidification can limit the shelf-life of some fermented dairy products including fresh lactic curd cheeses. The possibility of using high pressure processing (HPP) for controlling these problems was investigated in a commercially manufactured fresh lactic curd cheese (pH 4.3-4.4) and fermented milk models (pH 4.3-6.5). The effects of HPP at 300 and 600 MPa on inactivation of glycolytic enzymes of lactic acid bacteria were also evaluated. Fresh cheeses made from pasteurised bovine milk using a commercial Lactococcus starter preparation were treated with high pressures ranging from 200 to 600 MPa (less than or equal to 22°C, 5 min) under vacuum packaging conditions and subsequently stored at 4°C for 8 weeks. Treatment at greater than or equal to 300 MPa substantially reduced the viable count of Lactococcus and effectively prevented the outgrowth of yeasts and moulds for 6 to 8 weeks without adversely affecting the sensory and textural attributes of the product. However, it had no significant effects (p less than 0.01) on variation of titratable acidity during storage. Fermented milk models were prepared by individually growing Lactococcus lactis subsp. lactis C10, Lactococcus lactis subsp. cremoris BK5, Streptococcus thermophilus TS1, Lactobacillus acidophilus 2400 and Lactobacillus delbrueckii subsp. bulgaricus 2517 in UHT skim milk and diluting the resulting fermented milk with UHT skim milk up to pH 6.5. Pressure treatment of the milk models at pH 5.2 resulted in substantial inhibition of post-processing acidification during storage and markedly reduced the viable count of Lactococcus at both 300 and 600 MPa and other bacteria only at 600 MPa. Treatment of the milk model at 600 MPa decreased the viable counts of Candida zeylanoides and Candida lipolytica (wildtype spoilage yeasts of lactic curd cheese, added as challenge cultures) from 105 CFU mL-1 to below the detection limit (log 0 CFU mL-1) at all pH levels tested (pH 4.3-6.5) and effectively controlled their outgrowth for 8 weeks. Treatment of milk model at 300 MPa had a similar effect only on C. zeylanoides. The viable count of C. lipolytica was reduced by 2.6, 2.4 and 2.3 logs by treatment at 300 MPa at pH levels of 4.3, 5.2 and 6.5, respectively, which subsequently recovered by 2.9, 2.8 and 3.2 logs within 3 weeks. Glycolytic enzymes of various starter bacteria showed different responses to pressure treatment. The lactate dehydrogenase in L. lactis subsp. lactis and Lb. acidophilus was quite resistant to pressures up to 600 MPa, but it was almost completely inactivated in S. thermophilus at pressure levels as low as 300 MPa. The â-galactosidase in Lb. acidophilus was more pressure stable than â-galactosidase in S. thermophilus and Phospho-â-galactosidase in L. lactis subsp. lactis. The findings of this study suggests HPP at 300-600 MPa as an effective method for controlling the outgrowth of some spoilage yeasts and moulds in fresh lactic curd cheeses. The results obtained with selected lactic acid bacteria in fermented milk models can be used to assist in establishing HPP operating parameters for development of new generation cultured dairy products, of reduced acidity and extended shelf-life.
137

Effect Of High Hydrostatic Pressure On Quality Factors And Shelf Life Of Atlantic Mackerel (scomber Scombrus) And Red Mullet (mullus Barbatus)

Senturk, Tugce 01 September 2011 (has links) (PDF)
The ability of high hydrostatic pressure (HHP) to extend the shelf life of Atlantic mackerel (Scomber scombrus) and red mullet (Mullus barbatus) was assessed in this study. For that purpose, fillets of both atlantic mackerel and red mullet were subjected to pressure treatments at 200, 300, 400 MPa at 5, 10, 15&deg / C for 5 and 15 minutes. The influence of the treatments on Trimethylamine Nitrogen (TMA-N) level, lipid oxidation stability (Thiobarbituric Acid, TBA level) was investigated as well as color changes. The suitable combinations for Atlantic mackerel were determined as 200 MPa, 15&deg / C for 5 min and 400 MPa, 5&deg / C for 5 min / and for red mullet 200 MPa, 15&deg / C for 5 min. In the second stage, the shelf life of fish samples, which were treated with these conditions and stored at 4&deg / C, were studied by measurement of pH, color, sensorial features (appearance and odor), TMA-N, TBA, Total Volatile Basic Nitrogen (TVB-N), Histamine and Total Mesophilic Aerobic Count (TMAC) formations. Based on these analyses, the unpressurised mackerel samples were acceptable up to only 7 days compared to 17 and 19 days after 200 and 400 MPa treatments / respectively. For red mullet samples pressurization at 200 MPa extended the shelf life an additional 3 days (from 1 week to 10 days). HHP treatment in combination with chilled storage can improve the shelf life and quality of fish.
138

Investigating the impact of retail and household practices on the quality and safety of ready-to-eat and ready-to-cook foods

Manios, Stavros G. January 2012 (has links)
Bacterial responses to environmental stresses may be easily observed and predicted under controlled laboratory conditions. However, realistic conditions encountered during manufacturing, in retail or in households may cause unpredicted responses of spoilage or pathogenic bacteria. Therefore it is essential to identify and understand the microbial dynamics under such conditions. The overall aim of the present study was to simulate the most common environmental conditions and consumer-style practices during storage or preparation of Ready-to-Eat (RTE) and Ready-to-Cook (RTC) products in the domestic environment, and predict the microbial dynamics which may deteriorate the quality or compromise the safety of these foods. Aiming to develop a unified mathematical model for the prediction of the growth of the specific spoilage microorganisms (SSOs), the spoilage pattern of three RTE acidic spreads of low pH was described in relation to microbial, physicochemical and molecular changes during storage. Results showed that the spoilage profile of the products was primarily affected by the initial pH and the storage temperature, despite the differences in their formulation. These findings enabled the assessment of two unified models (polynomial and Ratkowsky) for the prediction of the growth of lactic acid bacteria (LAB; SSOs) in such acidic spreads, using only the initial pH, the concentration of undissociated acetic acid and the storage temperature. The models were validated under realistic conditions in household refrigerators. Despite the abrupt fluctuations of the temperature during validation procedure, they both were able to adequately predict the growth of LAB in the spreads. However, the initial contamination level was proved to be necessary and crucial for the accurate prediction of microbial dynamics. The time-temperature profiles of the validation procedure revealed that the suggested storage conditions were not followed promptly and, therefore, concerns were raised on the effect of such consumer mishandlings on the safety of foods. Therefore, the responses of Salmonella spp. and Escherichia coli O157:H7 to the stresses encountered during frozen storage, thawing and cooking of ground beef, simulating typical scenarios followed by the consumers, were evaluated. The results revealed that the guidelines issued by the food safety authorities lack of some specific points that may affect the safety of the final product, such as the duration of frozen storage and the method of cooking. In particular, it was found that the heat resistance of E. coli O157:H7 was likely increased after long term frozen storage, while cooking in pan-grill did not ensure the safety of the final product, even when cooked at the suggested temperature. As shown in the first study, the initial contamination level played a significant role on the predictions of the models and further on the shelf-life of the products. Therefore, the dynamics of realistically low initial populations of Listeria monocytogenes and Salmonella Typhimurium versus higher levels of the pathogens (such those used during in vitro trials) in RTE fresh-cut salads were compared. In addition, any potential uncertainty sources for the growth potential of the pathogens in broth-based simulations were investigated. Results showed that the growth variability of low inocula is highly affected by the marginal storage temperatures, the indigenous microflora and the availability of nutrients. Because of this, growth from low populations showed the likelihood to exceed the growth derived from unrealistically high inocula, suggesting that ―fail-dangerous‖ implications may derive from such challenge tests. Data derived from this part were compared with broth-based simulations and the results showed that high uncertainty should be expected when extrapolating such predictions from low initial populations in fresh-cut salads, due to the various factors affecting the microbial growth on a real food, which are (inevitably) ignored by broth-based models. Overall, the present Thesis highlights the significant impact of consumer mishandlings on the food safety and quality of foods and contributes to the identification of unpredicted potential risk origins in the domestic environment.
139

Avaliação da vida de prateleira de peito de frango sem pele sob refrigeração

Moura, Marcio Fernando Ducat 31 August 2011 (has links)
Made available in DSpace on 2015-04-17T14:49:21Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 939298 bytes, checksum: 4db0a28a49a01afe330ae2fff4b91cc0 (MD5) Previous issue date: 2011-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The shelf life of foods is the time allowed for food to be consumed safely on the microbiological aspects, physicochemical and sensory characteristics, and is a determining factor in production logistics, trade and consumption, considered in the cost of the product, especially when it comes to perishable foods, for the presence and growth of micro-organisms during production to consumption are inevitable and their study is essential for the development of conservation technologies as well as determining with regard to the risk which consumers are exposed to. In this work we simulated the conditions of time (fifteen days) and temperature (<2.0 ° C) as indicated by the manufacturer shelf life of the product analyzed and the evaluations performed microbiological and physico-chemical properties during times of 0, 5, 10 and 15 days for raw and under cooling (1.4 ± 0.6 ° C) chicken breast without skin. The samples were analyzed for the presence / absence of the microorganism Salmonella spp., quantification of mesophilic microorganisms, MPN- most probable number for the group of coliform bacteria, the presence / absence of the Escherichia coli and pH analysis. None of the samples showed the presence of Salmonella spp. during the study , however, 10 days time was the limit for guaranteeing the quality of the microorganism Fecal samples at 45 ° C, and 70% of samples unfit for human consumption and at odds with the precepts of sanitary legislation in force. It was found that the microbiological quality of chicken flesh had flaws, as demonstrated by the high number of mesophilic aerobic bacteria, coliforms at 35 ° C and the confirmed presence of E. coli in 20% of the samples, which may therefore be a potential risk for the occurrence of foodborne illnesses DVA. / A vida de prateleira dos alimentos é o tempo estabelecido para que o alimento seja consumido com segurança quanto aos aspectos microbiológicos, físico-químicos e sensoriais, sendo fator determinante na logística de produção, comércio e consumo, sendo considerado no custo do produto, principalmente quando se trata de alimentos perecíveis, pois a presença e o crescimento de micro-organismos durante a produção até o consumo são inevitáveis e seu estudo é essencial para o desenvolvimento de tecnologias de conservação e determinante quanto ao risco em que os consumidores estão expostos. Neste trabalho foram simuladas as condições de tempo (quinze dias) e temperatura (< 2,0°C) indicados pelo fabricante como vida de prateleira do produto analisado e realizadas as avaliações microbiológicas e físicoquímicas durante os tempos de 0, 5, 10 e 15 dias para peito de frango sem pele, cru e sobrefrigeração(1,4 ± 0,6 ºC). As amostras foram analisadas quanto a presença/ausência do microorganismo Salmonella spp., contagem de micro organismos mesófilos, NMP - número mais provável para o grupo de coliformes, presença/ausência de E. coli e análise de pH. Em nenhuma das amostras foi detectada a presença de Salmonella spp., durante o tempo de estudo, porém, o tempo de 10 dias mostrou-se como limite para garantia da qualidade das amostras para o microorganismo Coliformes a 45°C, estando com 70% das amostras impróprias ao consumo humano e em desacordo com o que preceitua a legislação sanitária vigente. Foi possível constatar que a qualidade microbiológica da carne de frango apresentou falhas, como demonstrado pelo elevado número de bactérias aeróbias mesófilas, coliformes a 35°C e confirmação da presença de E. coli em 20% das amostras, podendo, portanto, ser um risco em potencial para ocorrência de Doenças Veiculadas por Alimentos - DVA.
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Elaboração de bebida fermentada funcional tipo iogurte utilizando leite de cabra e extrato hidrossolúvel de soja

Ribeiro, José Evangelista Santos 26 February 2014 (has links)
Made available in DSpace on 2015-04-17T14:49:36Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2092428 bytes, checksum: 9f2660b1eca5b207292adc4d196cdd59 (MD5) Previous issue date: 2014-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The success of the food industry depends not only on sure foods are safety for consumers, but also the capacity to innovate and supply the market trends, like the demand for food products made from health benefits ingredients. In this way, this research aimed to develop and characterize a yogurt-like fermented beverage made from a mixture of goat s milk and water-soluble soy extract (WSSE), supplemented with inulin. To established the most suitable formulation, a Central Composite Design (CCD) in conjunction with Response Surface Methodology (RSM) was used, having as independent variables the concentrations of WSSE and inulin. The response variables were water holding capacity (WHC), syneresis index, pH, acidity, and rheological and sensory properties. By using that methodology was observed that increasing WSSE concentration was related to better results for rheological properties, WHC and syneresis index, whereas, a negative influence was observed on overall acceptability of the product. Inulin concentration, at the levels studied, showed a positive influence on apparent viscosity and overall acceptability of the beverages. By using the models obtained for response variables was elaborated a treatment containing the concentrations of WSSE and inulin that promoted the most suitable result. The fermented beverage elaborated was characterized for physicochemical and sensory properties and the refrigerated storage stability was analyzed during 28 days by evaluating microbiological, chemical and physical parameters. The results obtained from this treatment were compared with the results obtained from a control treatment made using goat s milk only and without inulin supplementation. The treatment containing WSSE and inulin showed better results for physical and chemical properties, showing better stability during refrigerated storage. However, control treatment showed a better overall acceptability, presenting aroma and taste more pleasant. Regarding to microbiological parameters, no significative differences were observed for these two treatments. / O sucesso da indústria de alimentos não depende apenas da certeza de que os alimentos são seguros para o consumo, mas também da habilidade para inovar e para atender as atuais tendências de mercado, como a demanda por alimentos elaborados a partir de ingredientes que, além de nutrir, trazem benefícios adicionais a saúde. Neste contexto, este trabalho objetivou desenvolver e caracterizar uma bebida fermentada tipo iogurte elaborada a partir de uma mistura composta por leite de cabra e extrato hidrossolúvel de soja (EHS), adicionada de inulina. Para a definição da formulação mais adequada foi utilizado um Delineamento Composto Central Rotacional (DCCR) em conjunto com a Metodologia de Superfície de Resposta (MSR), tendo como variáveis independentes as concentrações de EHS e inulina e como variáveis dependentes a capacidade de retenção de água, o índice de sinerese, pH, acidez e as propriedades reológicas e sensoriais. A partir desta metodologia, foi verificado que o aumento na concentração de EHS favoreceu a obtenção de melhores resultados para as propriedades reológicas, para a capacidade de retenção de água e para o índice de sinerese, no entanto, apresentou uma influência negativa sobre a aceitação sensorial do produto. A concentração de inulina, dentro dos níveis utilizados, influenciou de forma positiva sobre a viscosidade aparente e sobre a aceitação sensorial do produto. A partir dos modelos obtidos para as variáveis dependentes estudadas, foi elaborado um tratamento contendo as concentrações de EHS e inulina que forneceram os resultados mais satisfatórios. A bebida fermentada elaborada foi caracterizada quanto as propriedades físico-químicas e sensoriais e sua estabilidade foi avaliada durante um período de armazenamento refrigerado de 28 dias com relação a parâmetros microbiológicos, físicos e químicos. Os resultados obtidos a partir deste tratamento otimizado foram comparados com os resultados de um tratamento controle elaborado apenas com leite de cabra e sem a adição de inulina. O tratamento contendo EHS e inulina obteve melhores resultados com relação as propriedades físicas e químicas, apresentando melhor estabilidade durante o armazenamento. No entanto, o tratamento controle obteve uma melhor aceitação sensorial, apresentando sabor e aroma mais agradáveis. Com relação aos parâmetros microbiológicos, diferenças significativas não foram observadas entre estes dois tratamentos.

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