Rozprawy doktorskie na temat „Technologie hurdle”
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Mechmechani, Samah. "Hurdle technology using microencapsulated proteolytic enzymes and microencapsulated carvacrol to fight pathogenic bacterial biofilms". Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILR023.
The ambient operating environments in the food and medical sectors allow bacteria to adhere and develop on the substrates, resulting in the growth of resistant pathogenic bacterial biofilms. These pathogenic structures are responsible for several foodborne diseases and health-care associated infections. Consequently, to combat this public health burden, several strategies have recently been proposed which include chemical and mechanical removal. This work presents the different factors that influence bacterial adhesion and biofilm formation on abiotic surfaces, as well as biofilm resistance to disinfectants. The different strategies for biofilm prevention and eradication are described. Microencapsulation using spray-drying method for the formulation of anti-biofilm active components as a tool to ensure their stability and improves their biological activities are also presented. In this context, a study was conducted using carvacrol, a natural antimicrobial agent, to control biofilms of Pseudomonas aeruginosa and Enterococcus faecalis. Indeed, these two bacteria are responsible for several infections worldwide due to their persistence on abiotic surfaces in hospitals and food processing industries. Furthermore, in order to enhance the antimicrobial activity of carvacrol and reduce its volatility and low solubility in water, feed emulsions were prepared with sodium caseinate and maltodextrins and then spray dried to obtain dry carvacrol microcapsules. The results showed that carvacrol had a strong antimicrobial activity against both bacterial biofilms. Furthermore, our findings revealed that microencapsulation by spray drying significantly increased the antimicrobial activity of carvacrol while reducing the amounts used. Indeed, microencapsulated carvacrol was able to reduce biofilm below the detection limit for Pseudomonas aeruginosa and 5.5 log CFU mL-1 for Enterococcus faecalis after 15 min of treatment. However, the complete removal of biofilms from abiotic surfaces in medical and food sectors has proven difficult with the single use of disinfection strategy due to the high protection of the biofilm cells by the extracellular polymeric matrix. This matrix provides an initial protective barrier for the biofilm cells, and makes biofilms highly resistant to antimicrobial agents. The effectiveness of hurdle technology in removing biofilms using different strategies is discussed in this work. One of the hurdle technology approaches is the use of matrix-degrading enzymes that can disperse bacteria embedded in biofilms for more efficient disinfection when combined with biocide agents. Indeed, two proteolytic enzymes, pepsin and trypsin, targeting matrix proteins, have been studied for their potential to degrade biofilms of Pseudomonas aeruginosa and Enterococcus faecalis and their synergistic effect when combined with carvacrol. The direct analysis using epifluorescence microscopy allowed visualization of the dispersive activity of proteases and the lethal activity of carvacrol against the two bacterial biofilms. In addition, the combined pepsin or trypsin treatment with carvacrol showed more significant reduction of both biofilms compared to carvacrol treatment alone. Moreover, this reduction was more substantial after sequential treatment of both enzymes followed by carvacrol. However, the enzyme activity is highly influenced by environmental factors and is only optimal under restricted conditions. Another disadvantage of using enzymes is self-degradation, leading to instability. Indeed, protease microcapsules containing pepsin or trypsin complexed with pectin and maltodextrin have been prepared
McMahon, Carol Martha Mary. "Pathogen control in sous vide processing by thermal inactivation and hurdle technology". Thesis, University of Ulster, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388950.
Sahmurat, Fatma. "Hurdle Technologies Using Essential Oils And High Hydrostatic Pressure To Inactivate E. Coli In Fresh Beef". Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/83442.
Ph. D.
Provost, David 1959. "Hurdles in the business case for the Semantic Web". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17883.
Includes bibliographical references (leaves 29-34).
The nuclear winter that filled the vacuum created by the Internet implosion was characterized by highly conservative investments in new technologies. This was particularly true for Internet- and Web-oriented technologies since after all, being a believer just wasn't as popular as it used to be. However, life, business, and science go on, and the Web is no exception. This thesis will examine hurdles in the business case for the Semantic Web. In one sense, the Semantic Web is an extension or enhancement of the existing World Wide Web (Web). As we know it today, the Web is a rich medium that allows humans to express themselves, learn, interact, and reach an audience that was a pipe dream just a decade ago. At the same time, the Web is of limited utility to computers (machines). For example, a human being could easily recognize a postal address or the specifications of an order for steel; a machine could not. To a machine, these data would simply be elements to be rendered and displayed on a monitor, with no intrinsic or cumulative meaning. In this sense, one of the goals set for the Semantic Web is to create meaning and utility for machines that allows for interpretation and action with far less human intervention. Issues related to the challenges, practicalities, theories and opportunities of the Semantic Web will be discussed. In the process, hopefully, this thesis will identify some of the stepping stones in building a business case for this evolution. Notably, today's comments regarding the Semantic Web sound very similar to what was once said about the practicalities of eBusiness and the likelihood of its adoption.
by David Provost.
S.M.M.O.T.
Rodriguez, Leon Alexis, i Khushboo Singh. "Adoption hurdles faced by organizations embracing SAFe®". Thesis, Uppsala universitet, Industriell teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-411177.
Benli, Hakan. "Sequential application of epsilon-polylysine, lauric arginate and acidic calcium sulfate for inactivation of pathogens on raw chicken and beef". [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2965.
Hashimoto, Jorge Minoru. "Utilização da tecnologia dos metodos combinados na conservação do leite de coco". [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/322521.
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Doutorado
Doutor em Ciência de Alimentos
Crona, Elna, i Nathalie Johnsson. "Jämförelse av olika konserveringsmedel genom belastningstest i ett flytande livsmedel". Thesis, Högskolan Kristianstad, Fakulteten för naturvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-20949.
Introduction One third of food produced in the world is discarded (United Nations Development Program [UNDP], 2020) and food-destroying microorganisms are a common problem and a contributing cause of global food waste (Snyder & Worobo, 2018). The food industry therefore uses various hurdle techniques to minimize the risk of growth of spoilage organisms (Snyder & Worobo, 2018). One strategy to check whether different hurdle techniques meet their purpose is to expose foods in a challenge test. Aim The aim of the study was to compare the preservatives lingonberry juice and potassium sorbate + sodium benzoate and examine any physical and chemical changes over time through a challenge test on a liquid food product. Material and method A liquid food (n = 73 á 180 ml) was inoculated in a challenge test with log 2-3 microorganisms per ml food. Thereafter preservatives lingonberry juice (n = 24) or potassium sorbate + sodium benzoate (n = 25) were added. One third of the samples (n = 24) were left without preservatives. Sampling for analysis of growth, color, pH and viscosity (mPas) was performed at 0, 14 and 30 days after the food was inoculated with microorganisms. Results The results showed microbiological growth in all food products at day 0. Day 14 growth were found in the food with potassium sorbate + sodium benzoate and lingonberry juice. By the analysis on day 30 growth in the food with potassium sorbate + sodium benzoate and in the food without preservatives were showed. Over time physical changes of viscosity and chemical changes of pH occurred. Regard to color only marginal changes occurred. Conclusion The result of the challenge test showed that lingonberry juice is the preservative that has the best effect regard to product stability through inhibiting the added microorganisms. The results of the physical measurements showed changes regard to viscosity over time. Color only showed marginal changes. The result of the chemical measurement showed changes of pH over time.
Amadori, Sonny. "Utilizzo del citral per aumentare l'efficacia di trattamenti con campi elettrici pulsati". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16840/.
Andrade, Ivana Morais Geremias de. "Estimativa da vida de prateleira de caldo de cana padronizado estocado sob refrigeração". Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/74/74132/tde-22092014-112413/.
The present study consisted in standardizing the total soluble solids (SS) and titratable acidity (TA) ratio, in small scale processing and in estimating the shelf-life (SL) of sugarcane juice stored under ideal, commercial and abusive temperature conditions. A central composite rotational design with eleven formulations of sugarcane juice was used to investigate the ratio of the formulation that resulted in the best sensory acceptance in a wide range of SS (13,1 a 25,9 ºBrix) and TA (0,02 a 0,09% citric acid). Found the best formulation, three batches of standardized sugarcane juice were processed (L1, L2 and L3). The juice´s stabilization was based on the following combination of thermal and non-thermal methods: acidification, pasteurization (95 °C/30 s), aseptic filling in polyethylene terephthalate (PET) bottles and refrigerated storage. Physico-chemical, microbiological and enzymatic tests, including the determination of the peroxidase (POD) and polyphenol oxidase (PPO) activities, were performed in the fresh and freshly processed (time zero of SL) juice. For the SL study, standardized pasteurized sugarcane juice samples were stored at temperatures of 4, 8, 12 and -18 °C (control), kept in the dark. The estimate of the product´s SL was based on microbiological and sensory tests. The evaluation of the microbiological stability was based on the psychrotrophic bacteria and fungi counts. Nine-point hedonic scale tests for appearance and flavor evaluation were used in order to assess the sensory stability. The mean values of sensory acceptance, for overall impression, of the eleven formulations showed no statistical difference (p > 0.05) among them. It was found that only the effect of TA was significant (p < 0.05). The chosen formulation for sugarcane juice standardization was that one with TA 0.09 % (pH near 3.9) and SS 19.5 ºBrix. For the freshly processed standardized pasteurized juice, the pH was less than 4.4 in L1, L2 and L3. The mesophilic counts did not exceed 50 CFU/mL. The presence of coliforms at 45 ºC and Salmonella was no confirmed. The average POD and PPO activities were 2.11 U/mL and 1.03 U/mL respectively. The psychrotrophic bacteria and fungi counts did not exceed 102 CFU/mL. The juice´s SL stored at 4, 8 and 12 °C were 71, 74 and 21 days, respectively. It was concluded that the juice was well accepted in a wide range of SS and TA, and the combination of methods was effective in reducing the enzyme activity and microbial counts. Moreover, temperatures of 4 and 8 °C were proved to be effective in maintaining the sugarcane juice´s quality for a period of time compatible with the consumer market demand.
Kunitake, Mariana Tomie. "Processamento e estabilidade de caldo de cana acidificado". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/74/74132/tde-09052012-113918/.
Sugarcane juice, either pure or with fruit pulp addition, is an appreciated beverage in Brazil. The aim of this research was to evaluate the shelf-life of sugarcane juice mixed with passion fruit pulp (4% w/w). Nine batches were processed at 85, 90 and 95 °C/30 s, in three replicates. The pasteurized beverage was aseptically filled into polyethylene terephthalate (PET) bottles and stored at 7 °C without light exposure. pH, soluble solids and titrable acidity were measured during storage. The content of vitamin C was analyzed both in fresh sugar cane juice and pasteurized beverage. Polyphenoloxidase (PPO) and peroxidase (POD) activities were determined both before and after processing. Microbiological stability evaluation was based on psychrotrophic bacteria and fungi counts. Sensory acceptance was estimated by assigning a liking score on a 7-point hedonic scale to the attributes appearance, flavor, taste and overall appreciation. The mean values for pH, soluble solids and titratable acidity ranged from 3.8 to 4.3, 15 to 24 °Brix, and 0.13 to 0.17% of citric acid, respectively, for all processed batches. The passion fruit pulp did not increase the ascorbic acid content in the pasteurized product which ranged from 2.6 to 2.8 mg / 100 mL of beverage. The PPO activity varied from 3.1 to 40.3 U/mL for the nine acidified sugarcane juice batches before pasteurization. The three pasteurization binomials were effective for enzyme inactivation. The POD activity ranged from 69.8 to 220.4 U/mL. However, only processing at 95 °C achieved complete inactivation. The bacteria and fungi counts in all nine pasteurized batches were lower than 2 log CFU/mL up to 90 days of storage. The product achieved scores between 5 and 6 for all sensory attributes evaluated after 30 days of storage. The estimated shelf-life for beverage processed at 85, 90 and 95 °C/30 s was 31, 39 and 52 days, respectively. It was concluded that pasteurization temperature had a positive effect on beverage stability. Nevertheless, the decrease in flavor acceptance was the main limiting factor for the product\'s shelf-life.
Salavessa, João José Sotto Maior. "Salsicharia tradicional da zona do Pinhal : caracterização e melhoramento da tecnologia de fabrico dos Maranhos". Doctoral thesis, Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária, 2009. http://hdl.handle.net/10400.5/2843.
Este trabalho visou caracterizar a tecnologia tradicional de fabrico dos Maranhos, determinar as suas características físico-químicas, microbiológicas e organolépticas, identificar os factores que limitam a sua conservação e que dificultam a sua distribuição, antecipar os potenciais perigos que possam advir do seu consumo e, experimentar alterações tecnológicas capazes de melhorar e adequar o produto às exigências do mercado actual. Idealizaram-se e experimentaram-se alterações tecnológicas assentes na conjugação de diferentes barreiras físico-químicas, testando-se a acção de diferentes combinações dos aditivos nitrito de sódio (E250), ácido ascórbico (E300), sorbato de potássio (E202) e metabissulfito de sódio (E223) em Maranhos processados termicamente, embalados a vácuo e conservados a 4 ºC, recorrendo a ensaios de validade com controlo periódico dos parâmetros físico-químicos, microbiológicos e sensoriais, estabelecidos de acordo com a sua relevância para a qualidade do produto. No Lote 2 e também no Lote 4 foi possível alargar a validade do produto já cozinhado para 3 semanas, cumprindo desta forma com as exigências da moderna distribuição e melhorando inclusivamente conforme foi perceptível pela avaliação do painel de provadores, algumas das suas características organolépticas.
ABSTRACT - Traditional meat products from “Pinhal” zone : characterization and technological improvement of “Maranhos” manufacturing process - The aim of this work was to characterize the traditional manufacturing process of “Maranhos” and determinate its physical-chemical, microbiological and sensorial attributes, identify the factors that compromises its shelf-life and commercial distribution, anticipate potentials hazards due to its consumption and experiment technological changes in order to improve and add value to the product according to the present market requirements. Technological changes based on the combined action of some different physical-chemical hurdles were idealized and experimented. The impact of some different combinations of food additives, sodium nitrite (E250), ascorbic acid (E300), potassium sorbate (E202) and sodium metabisulphite (E223) were evaluated by shelf-life trials, based on regular control of some previous established physical-chemical, microbiological and sensorial attributes considered relevant to the quality of refrigerated (4ºC) vacuum packaged cooked “Maranhos”. An extension of 3 weeks at shelf-life of this cooked meat product was attained in batch 2 and also in batch 4, according to the requests of modern commercial distribution, improving also some of the product sensory attributes has it was revealed by the sensory analysis expertise’s.
Bolsa de Investigação no âmbito do POS _C - Desenvolver Competências - Medida 1.2 da Fundação para a Ciência e Tecnologia Ref. SFRH/BD/34186/2006.
Tribst, Alline Artigiani Lima 1983. "Efeito do processamento por alta pressão dinamica combinado com tratamento termico brando na inativação de Aspergillus niger em nectar de manga". [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254850.
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O néctar de manga é apreciado por sua cor e aroma. Este produto, pela sua alta acidez, pode ser contaminado por bolores, dentre os quais são de grande relevância aqueles capazes de sobreviver ao processamento térmico. O processamento a alta pressão dinâmica (APD) é um tratamento ¿a frio¿ realizado para inativação de microrganismos visando uma melhor qualidade sensorial e nutricional do produto obtido. Neste estudo, avaliou-se o efeito do processamento a APD isoladamente ou combinado com tratamento térmico (TT) brando na inativação de Aspergillus niger em néctar de manga e, posteriormente, foi realizada a avaliação do efeito dos processos sobre a cor e a concentração de vitamina C do néctar. Paralelamente foi desenvolvida uma metodologia para limpeza e sanificação do equipamento e um processo para a redução de viscosidade do néctar de manga. Foram estudadas pressões entre 100 e 300 MPa para a inativação do Aspergillus niger. A pressão de 300 MPa inativou toda a carga inicial (> 6,24 reduções decimais), 200 MPa provocou uma inativação parcial (aproximadamente 2 ciclos) e, pressões inferiores a 150 MPa não resultaram em inativação significativa do A. niger. Quando o processo de APD foi associado à TT brando (80ºC/15minutos) foi observado um efeito sinérgico entre pré tratamento a APD e posterior TT (aproximadamente 1 ciclo logaritmo); já quando utilizado pré TT seguido de tratamento a APD, foi observado apenas um efeito aditivo. Utilizando-se aplicação de APD seguida de TT, foi realizado um planejamento experimental fixando-se a pressão em 200 MPa e variando-se temperatura e tempo do TT e ratio do néctar de manga (brix/acidez), de forma a obter um modelo que descrevesse o processo. Os resultados indicaram que tempo e temperatura afetaram positivamente a inativação e o ratio do néctar afetou negativamente. A partir do modelo foram estabelecidos que processos a 200 MPa seguido de TT a 73,5ºC/10 minutos ou 61,5ºC/20 minutos eram suficientes para obter 5 reduções decimais do bolor. A avaliação desses processos combinados, do processo térmico tradicional (100ºC/10 minutos) e do processo utilizando apenas pressão (300 MPa) sobre o conteúdo de vitamina C e cor do néctar demonstrou uma inativação de vitamina C muito similar para todos os processos (perdas de aproximadamente 45%) e uma melhor retenção de cor para os produtos processados à APD. O desenho do processo de limpeza e sanificação para o equipamento foi considerado eficaz uma vez que reduziu para < 1 UFC.mL-1 a contaminação de A.niger inicial de aproximadamente 106 UFC.mL-1 na água de enxágüe. Foi utilizada concentração de 0,05% de ácido peracético e 2,5% de detergente comercial cujos princípios ativos eram o toluenosulfonato de sódio e cloreto de didecilmetilamônio. O processo de redução de viscosidade do néctar também foi efetivo através de seu pré tratamento com enzimas pectinolíticas e celulases, que reduziram a viscosidade inicial do néctar em 50%. Pelos resultados obtidos no presente trabalho, observa-se que a APD isoladamente ou aplicada junto com TT brando é uma alternativa viável para a inativação de A. niger termorresistente em néctar de manga. O processo teve efeito negativo sobre a vitamina C do néctar de manga, o que pode ser atribuído tanto à presença de oxigênio na amostra quanto à presença de selos metálicos no equipamento (selos de berílio-cobre) que promovem a passagem de íons metálicos para o suco, os quais atuam como pró-oxidantes de vitamina C, agravando a oxidação da vitamina
Abstract: Mango nectar is appreciated by its color and flavor. Due to its high acidity, this nectar can be contaminated by molds and the most important molds are those able to survive to the heating process. The dynamic high pressure (DHP) is a cold treatment used to inactivate microorganisms with better nutritional and sensory retention in food. In this study, the DHP process isolated or combined with mild thermal treatment (TT) was used to inactivate Aspergillus niger in mango nectar. The effects of these processes were evaluated on color and vitamin C retention. In parallel, a methodology was developed to clean in place (CIP) the DHP equipment. A process to reduce the viscosity of mango nectar was also developed. Pressures between 100 and 300 MPa were studied to Aspergillus niger inactivation. Pressure of 300 MPa completely inactivated the initial load (> 6.24 decimal reduction), 200 MPa caused a partial inactivation (2 log cycles) and pressures up to 150 MPa did not inactivate the mold. A synergistic effect was observed when pre treatment of DHP was associated to mild TT (80ºC/ 15 minutes) with increase of 1 log cycle on mold inactivation. However, only an additive effect was observed when pre TT was associated to DHP. An experimental design was carried out using fixed pressure of 200 Mpa followed by mild TT. Temperature and time of thermal treatment and ratio of mango nectar (brix/acidity) was select as experimental design variables. The results indicated that time and temperature affected positively and nectar ratio affected negatively the mold inactivation. By the mathematical model, process of 200 MPa followed by 73.5ºC/10 minutes or by 61.5ºC/20 minutes was able to promote 5 decimal reduction of A. niger. The effect of these processes, the conventional heat and DHP at 300 MPa on vitamin C concentration and nectar color retention was evaluated. The vitamin C losses were around 45% for all processes studied but better color retention was observed on the nectar processed by DHP. The CIP design was considered efficient once it was able to reduce the initial load of A. niger from ~106 CFU.mL-1 to <1 CFU.mL-1. 2.5% of a commercial detergent (active agents: sodium toluenosulfonate and didecylmethilamonium chlorine) and peracetic acid at 0.05% were used in this process. The nectar viscosity reduction was effective by using pectic enzymes and celullase, being able to reduce natural mango nectar viscosity by 50%. The results obtained indicated that DHP isolated or combined with mild thermal treatment are a viable alternative to inactivate A. niger in mango nectar. The process has a negative effect on vitamin C retention. It can be attributed to the oxygen dissolved in mango nectar and also to metals seals of equipment (Be-Cu) which can had promoted an increase in metallic ions concentration in nectar. These ions are pro oxidant of vitamin C, resulting in intense vitamin oxidation
Mestrado
Mestre em Tecnologia de Alimentos
Rodriguez, Gonzalez Oscar. "Hurdle technologies: microbial inactivation by pulsed electric fields during milk processing". Thesis, 2010. http://hdl.handle.net/10214/2445.
Dairy Farmers of Ontario, Natural Sciences and Engineering Research Council.
黃書政. "Application of Hurdle Technology on Chinese Sausage Processing and Preservation". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/31733625041030646293.
國立海洋大學
食品科學系碩士在職專班
89
Chinese sausage is a popular product in Taiwan. The preserves are usually added in the product to extend it’s shelf-life. However, the amount used in some commercial products is over the limit. Therefore, in this study we apply the hurdle technology to Chinese sausage processing and preservation instead of single method to improve its quality. Generally, the quality indices of Chinese sausage were represented by the measuring of the color ( a value ) and bacteria (TPC). Among 10 additives used in this study, glucono-delta-lactone, propylene glycol, sodium lactate, potassium sorbate had a more significant effect on the inhibition of bacteria. Therefore, three additives glucono-delta-lactone, propylene glycol, sodium lactate were used as the hurdle factors. To employ these factors systematically, the experiments were designed by using response surface method (RSM). A central rotatable design three-variable and three-level was adopted. The amount of glucono-delta-lactone (0.4%), propylene glycol (0.5%), sodium lactate (1.75%) and potassium sorbate (0.1%) with ±50% were added to evaluate their combined effect on sausage quality. The results showed the optimal condition for the quality of vacuum packaged Chinese sausage stored at 4℃ was propylene glycol 0.5%, glucono-delta-lactone 0.70∼0.80% and sodium lactate 1.75∼2.70%. If potassium sorbate was proposed as a factor, the optimal condition was sodium lactate 1.75%, glucono-delta-lactone 0.40∼0.80% and potassium sorbate 0.18∼0.20%. On the other head, the optimal condition for atmosphere package sausage stored at 25℃ was propylene glycol 0.5%, glucono-delta-lactone 0.50∼0.80% and sodium lactate 1.00∼3.00%. If potassium sorbate was used, the addition of sodium lactate 1.75%, glucono-delta-lactone 0.40∼0.70% and potassium sorbate 0.18∼0.20% could obtain a similar result. There is no significant difference of sensory evaluation between the conventional sausage and the product processed by hurdle technology. However, the latter product had a longer shelf-life than the former.
Chiu, Yu-Hsing, i 邱禹馨. "Application of Hurdle Technology for Improving the Quality of Dried Radish". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/15118906249262244114.
中國文化大學
生活應用科學研究所
98
Dried radish is a Chinese traditional pickled product. Because it is an intermediate moisture food, it can preserved longer by food preservative added. However, the over load and illegally preservative added lead people pay more attention to the sanitary quality of dried radish. This study will use the hurdle technology, by gathering several bacteria inhibition factor to increase the quality and economic benefits and decrease the quantity of preservative of dried radish. Furthermore, it will exploit the Taguchi method using orthogonal array and smaller-the-better S/N ratios to confirm the most important of hurdle factor and the optimum process condition of dried radish. The result found that the optimum process condition of dried radish is desalination of raw material in 25 ℃ for 2 hours then dehydration. After that, it will added 0.3 % cinnamon powder, 0.3 % incinerated oyster shell powder and 4.76 % garlic into 100 % sorbitol solution as preservative and soaked for 2 hours. Then, the raw material will to air-dried in 80 ℃ for 30 minutes, and then cooled by 15 ppm ozone for 20 minutes. The result also found that the total count of dried radish which is between 2.39-2.84 log CFU/g processed by optimum process condition (experiment group) and storage at 25 ℃ for 0-5 weeks, and have no yeast and mold growth. On the other hand, the control group of dried radish was found mold growth after 4 weeks storage. Compared with the sensory evaluation score, the result showed the texture, color, flavor and overall acceptability that of the dried radish processed by optimum process condition are better than control group. The result showed dried radish processed by optimum process condition not only increase the shelf-life by gentle processing ways, but also can accepted by consumers.
Lin, Sin-Rong, i 林欣榮. "Application of Hurdle Technology to Making Tou-Kan Products in Vaccum Package". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/74395523160811529563.
國立中興大學
食品暨應用生物科技學系所
99
Since tou-kan curd is high in nutrition and water activity, it’s a very suitable environment for micro-organisms to grow in. Its vacuum packaging is particularly susceptible to contamination from Clostridium botulinum. In order to avoid this risk, this study reduced the dried bean curd’s (both the large and small types) pH to under 4.60 or its water activity to under 0.85. The vacuum packaging was pasteurized in order to develop the contamination prevention hurdle technology. The study prepared a low-pH soaking liquid composed of polyphosphate (U, Tarisan U) or a low water-activity liquid composed of glycerol, propylene glycol, and salt. The bean curd was soaked in this, reducing the pH to below 4.6 and the water activity to below 0.85. The product storage study results showed that reducing the pH and water activity and then using vaccuum packaging and sterilization allowed the bean curd to be preserved for at least four weeks at below 7℃. At below 25℃, it could be preserved for at least 10 days. During the storage period, the total plate count, aerobic quality, and number of anaerobic spores were not tested. The study showed that hurdles such as pH value, water activity, low-temperature sterilization, and cold storage could be combined to produce sanitary vacuum-packaged tou-kan curd products.
Shi, Yao Xiang, i 施耀翔. "Improvement of Qualityof Dried Soybean Curd by Hurdle Technology with Ozone and Additives". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/79243033391980669945.
中國文化大學
生活應用科學研究所
97
The dried soybean curd is one of the soybean processed food and its pH value is about 5.8 to 6.6. Dried soybean curd contains plenty of nutrients which make it putrefactive easily, therefore manufacturer usually adds preservative to increase the shelf-life. The present study is going to use the hurdle technology and Taguchi method to increase the shelf-life of the product. The Taguchi method will use the orthogonal array and smaller-the-better S/N ratios to confirm the optimum hurdle factors. Results show that the optimum process is: soaked soybean in 4℃ water for 20 hours and add mix coagulant (CaSO4 0.29% and glucono - δ - lactone 0.4 % and cinnamon powder 0.1%) then press to form the curd, then cooked in boiling water for 25 minute and cooling by 15 ppm ozone air for 40 minute. This process could reduce 99 % of total bacterial count of dried soybean curd. Both soaking and ozone cooling process are the most important factor which contribution above 99%. The predictive value in confirmation experiment is close to the control value, which proved Taguchi method could used to predicate the bacterial growth in dried soybean curd process. Then, the dried soybean curd processed by 3 kind of conditions: (1)add 600 ppm benzoic acid, (2) soak in 30% H2O2 for 5 minute, and (3)processed by the optimum hurdle technology condition, and then incubate them in 37℃ for 12 hours. The total count of final dried soybean curds were 6.94, 0 and 5.18 log CFU/g respectively, and the total count of control group was 7.75 log CFU/g. According to the sensory analysis result show that commercial dried soybean curd is better than the dried soybean curd made by the optimum hurdle technology condition in overall acceptability. However, the dried soybean curd processed by the optimum hurdle technology condition had longer shelf-life. Therefore, the results still can be recommended as a commercial process condition for dried soybean curd make.
Chen, Ke-Wen, i 陳科文. "Application of Hurdle Technology for Improving the Manufacturing Process of Frozen Rice Cake". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/9j955x.
國立臺灣海洋大學
食品科學系
106
This study is aimed to adopt different process variables to improve shelf life of rice cake, treatments including frozen rice cake without preservatives, change frozen storage to refrigerated storage, and control environmental hygiene (lower the relative humidity, spray chlorine dioxide), same proportion degrees brix of pure rice cake and stuffing (40:40, 50:50, 60:60 °Brix), different water content of sprinkled powder (6%, 8%, 10%), different packaging material (PE, KNY/LLDPE, KNY/LLDPE and deoxidizer) as hurdle factors of the manufacturing process of rice cake. Samples were taken at zeroth, fourth, seventh, tenth, fourteenth, fifteenth day, and quality criteria including moisture, water activity, total plate count, yeast and mold, hardness, springiness, chewiness of rice cake under refrigerated storage were analyzed. The results demonstrated that spray 1000 ppm chlorine dioxide was significantly more effective on control air-borne bacteria counts than control the relative humidity under less than 60%. During refrigerated storage, the moisture of each group showed a tendency of rise slowly, while the water activity did not change significantly. Higher concentration (in terms of Brix), low moisture content of sprinkled powder, low permeability packaging material and deoxidizer showed the better hurdle effects on inhibition of microbial growth. Thus, the combination of above hurdle factors, the shelf life could be extended to 15 days under refrigeration as compared to 4 days without adding preservatives. In terms of textural profile analysis, hardness and chewiness were mainly affected by Brix, followed by packaging materials, the variations in springiness was not significantly affected by the hurdle factors. Comprehensively consider both microbial growth and maintenance of texture (lower hardness and higher springiness and chewiness), combined 50:50 °Brix of pure rice cake and stuffing, 8% sprinkled powder, KNY/LLDPE and deoxidizer were the most suitable formula for the product under refrigerated storage.
Pu, Hsiao-Ju, i 蒲孝如. "Improvement of Microbial Quality of Dried Soybean Curd of Taoyuan - Daxi Area by Hurdle Technology". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/29609243176415549017.
國立臺灣大學
食品科技研究所
94
The dried soybean curds from Taoyuan County contains about, 70-90 % water, and water activity is about 0.8.The pH is around 6.0 - 7.0 which provides a good growth condition for spoilage organisms. Generally, after 12 hours of storage under room temperature, dried soybean curd will spoil and form slime on the surface. The spoilage organism isolated from dried soybean curd of Taoyuan County in this study was found to be Acinetobacter sp. Objective of this study is to improve the microbial quality of dried soybean curd in Taoyuan- Daxi area by combine several GRAS materials. According to the results of RSM, we decide the use of benzoic acid (420 ppm) and phosphoric acid (300 ppm) in treating dried soybean curd when the temperature of environment is 25℃ and the pH of soybean curd is 5 to minimize the growth of Serratia liquefaciens. The growth of indicator organisms, Serratia liquefaciens, can be inhibited by anise, cinnamon and clove and the minimum inhibitory concentration for anise, cinnamon, and clove are 6 %, 12% and 20 %, respectively. Pseudomonas fluorescens can be inhibited by clove, with a minimum inhibitory concentration of 16 %. While Acinetobacter lwoffii can be inhibited by cinnamon and clove, both with a minimum inhibitory concentration of 3 %. The combinations of benzoic acid 420 ppm, phosphoric acid or citric acid 300 ppm, cinnamon 3 %, anise 4 %, and clove 3 % in the bittern could extend the shelf life of dried soybean curd from 12 hours to 48 hours under 25℃. The total count of dried soybean curd decrease with the storage time under 5℃.