Increasing interest has been shown in the irradiation sterilization and irradiation pasteurization of foods, but problems of off-flavors and odors are still unsolved, especially in the case of dairy products. From the flavor chemistry point of view, milk lipids are very highly susceptible to irradiation effects. Therefore, this investigation was designed to study some irradiation induced reactions involving flavor changes in the milk fat and to identify the volatile components produced in the milk fat upon irradiation. Milk fat, prepared from raw sweet cream and washed free of phospholipids, was first irradiated in the presence of air and under vacuum in glass vials at 4.5 Mrad with gamma rays from cobalt-60. The irradiation resulted in increase in TBA number, peroxide value, total monocarbonyls, bleaching of color, slightly rancid and typical candle-like off-flavors. Free fatty acids were also produced upon irradiation. The changes were more drastic in air along with production of a slight oxidized flavor. The monocarbonyls identified by column and paper chromatographic methods in irradiated milk fat include: C₁ through C₁₂, C₁₄ , and C₁₆ n-alkanals; C₃ through C₉, C₁₁, C₁₃ and C₁₅ alk-2-ones with only traces of C₆ and C₈ alk-2- ones; and C₅, C₆, C₉, and C₁₂ alk-2-enals. Irradiation of milk fat that had been dried over calcium hydride also caused free fatty acid production, especially short chain fatty acids. Methyl octanoate treated with calcium hydride and irradiated at 1.5, 3.0, 4.5, and 6.0 Mrad yielded small quantities of free octanoic acid, confirming that irradiation caused fission of the ester linkage even when traces of water were removed. The quantities of octanoic acid formed increased with increasing dose of irradiation. For identification of volatile components, the milk fat was irradiated in 307x409 'C' enameled cans under vacuum. The headspace analysis showed some air still left in the cans. Irradiation resulted in consumption of oxygen and production of hydrogen, carbon monoxide, carbon dioxide, and methane as identified in the headspace gases. The volatiles were isolated from the irradiated and control milk fats by low temperature, vacuum steam distillation at 40°C and 1-2 mm Hg. The volatile components were then extracted from the aqueous distillate with ethyl ether. The ethyl ether extract exhibited the typical candle-like defect. The ethyl ether concentrate was analyzed by combination of GLC and fast-scan mass spectrometric techniques. Identification of various components was achieved on the basis of mass spectral data and coincidence of gas chromatographic retention times. In the case of the components for which only GLC t[subscript r]/t[subscript r] evidence was available or the mass spectra obtained were not satisfactory, the identity assigned was only tentative. The volatile compounds that were positively identified to be present in irradiated milk fat are given below: n-Alkanes C₅ through C₁₇ 1-Alkenes C₅, C₇ through C₁₇ Fatty acids C₄, C₆, C₈ and C₁₀ n-Alkanals C₅ through C₁₁ Others γ-decalactone, δ-decalactone, 2-heptanone, benzene, ethyl acetate, chloroform, and dichlorobenzene. The tentative identification was obtained for the following compounds: γ-lactones C₆ and C₈ δ-lactones C₆, C₈, C₁₁, and C₁₂ 1, ?-alkadienes C₁₀, C₁₁, C₁₂, C₁₆ and C₁₇ iso-alkanes C₁₀, C₁₁, C₁₂, and C₁₃ Others methyl hexanoate, 2-hexanone, 4-heptanone and n-dodecanal. The compounds present in unirradiated control milk fat included: short chain fatty acids (C₄, C₆, C₈, and C₁₀), C₈, C₁₀, and C₁₂ δ-lactones, 2-heptanone, chloroform, dichlorobenzene, benzene, toluene, and ethyl-benzene. Only tentative identity was established for most of these components in control milk fat. Possible reaction mechanisms are presented for the formation of the compounds in irradiated milk fat. / Graduation date: 1966

Στη παρούσα εργασία καταβάλλεται μια προσπάθεια ελέγχου των μονάδων παστερίωσης που αποκτώνται κατά τη διάρκεια της παστερίωσης, ακόμα και σε περιπτώσεις διακοπής της ομαλής της λειτουργίας. / In the present study,an attempt was made to control the pasteurization units acquired during the procedure of pasteurization,even in cases of disruption of normal operation.

Thesis (MScVoedselwet)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Milk has been identified as having the potential of being a carrier of human pathogens, and it is thus essential to eliminate or reduce the likelihood of milk borne contamination. This problem of milk contamination is generally solved by the process of pasteurisation which is achieved by heating the "raw" material for a sufficient period of time to destroy any pathogenic and spoilage bacteria which may be present at a temperature of below 100°C. Presently, there are two basic methods of pasteurisation in use in the dairy industry, the LTLT and the HTST methods, where the applied heat treatment is considered sufficient to ensure public safety and adequate keeping quality. In addition to these, there is another method, the "pot" pasteurisation, to be found in Southern Africa that was designed to eliminate potential pathogenic and spoilage bacteria present in raw milk. As far as it is known no thermal studies have been done on the "pot" pasteurisation method. The objectives of this study were to determine the impact of different milk pasteurisation temperature and time combinations on the survival of selected microbes. The accuracy of the "pot" pasteurisation method and how it differs from the other pasteurisation methods was also determined using the same selected microbes. The six selected microbes were thermally inactivated by using the LTLT, HTST and the "pot" pasteurisation methods at low and high inoculum levels of 104 and 106 cfu.ml-1. The thermal death curves were constructed for each selected species. The selected microbes included the strains Bacillus cereus (S4), Chryseobacterium meningosepticum (S5), Pseudomonas putida (S6), Acinetobacter baumannii (C3), Escherichia coli (58) and Candida lipolytica (G1). Survivors were enumerated after heating for 0, 5, 10, 15, 20, 25, 30, 35 and 40 min for both the LTLT and HTST pasteurisation methods and after heating for 0, 10, 20 and 30 min for the "pot" pasteurisation method. The results from this study showed that with the exception of the B. cereus strain, the other selected microbes at both high and low concentration levels did not survive the LTLT or the HTST pasteurisation methods. It was found that for all the organisms used in this study, there was a rapid initial death rate just before the required pasteurisation temperatures of 63°, 72° and 90°C were reached, during the "come-up" period. In contrast, the results from the "pot" pasteuriser showed that theB. cereus (S4), Chr. meningosepticum (S5), P. putida (S6), A. baumannii (C3) and E. coli (58) strains survived the pasteurisation conditions applied. From these results it was thus concluded that the "pot" pasteuriser under the conditions evaluated in this study, did not pasteurise effectively. Therefore, it is recommended that the manufacturer improves the heating quality of the "pot" pasteuriser. As it was found that only the B. cereus (S4) strain survived all the different pasteurisation methods, future research needs to be done to determine at which temperature this heat resistant bacterial strain will be destroyed. This is very important because there is a need to destroy all the spoilage microorganisms that can lead to the deterioration of food products. / AFRIKAANSE OPSOMMING: Melk is 'n potensiële draer van mikrobes wat patogenies is vir die mens. Dit is dus essensiëel om die besmetting van melk te verlaag of te elimineer. Die probleem van melkbesmetting word opgelos deur die proses van pasteurisasie. Die proses word toegepas deur verhitting van die rou material vir 'n voldoende periode om patogeniese en bederf organismes te vernietig. Temperature onder 100°C word gebruik. In die suiwelbedryf word twee basiese metodes gebruik: die LTLT (lae temperatuur, lang tyd) metode en die HTKT (hoë temperatuur, kort tyd) metode. Albei hittebehandelings is voldoende om publieke veiligheid en 'n genoegsame rakleeftyd te verseker. 'n Derde metode, "pot" pasteurisasie, word in Suidelike Afrika gebruik. Die metode is ontwikkel om potensiële patogene en bederf organismes in rou melk te elimineer. Die probleem is dat daar geen navorsing op die temperatuur eienskappe van die “pot" metode gedoen is nie. Die doelwitte van hierdie navorsing was om die effek van verskillende temperatuur:tyd kombinasies op die oorlewing van sekere mikrobes te bepaal. Die akkuraatheid van die "pot" metode en die manier hoe dit van ander metodes verskil, is ook in ag geneem. Die navorsing is ten alle tye gebaseer op die geselekteerde mikroorganismes. Die ses geselekteerde spesies van mikrobes is vernietig deur middel van die LTLT, HTKT en "pot" pasteurisasie metodes. Die mikrobes is geïnaktiveer teen lae en hoë inokulums van 104 en 106 kve.ml-1. Terminale dodings kurwes is opgestel vir elke geselekteerde spesie. Die mikrobes van belang is Bacillus cereus (S4), Chryseobacterium meningosepticum (S5), Pseudomonas putida (S6), Acinetobacter baumannii (C3), Escherichia coli (58) en Candida lipolytica (G1). Die oorlewende mikroorganismes is na hitte behandelings van 0, 5, 10, 15, 20, 25, 30, 35 en 40 minute vir beide die LTLT en die HTKT pasteurisasie metodes en na hitte behandelings van 0, 10, 20, en 30 minute vir die "pot" pasteurisasie metode getel. Die resultate van die navorsing dui aan dat, behalwe vir B. cereus, die geselekteerde mikrobes teen beide lae en hoë konsentrasies nie die LTLT en die HTKT metodes oorleef het nie. Daar is gevind dat, vir al die organismes, vinnige aanvanklike dodingstempos teenwoordig was net voor die noodsaaklike pasteurisasie temperatuur van 63°, 72° en 90°C bereik is, gedurende die "come-up" periode. Inteenstelling hiermee het die resultate van die "pot" metode bewys dat B.cereus (S4), Chr. meningosepticum (S5), P. putida (S6), A. baumannii (C3) en E. coli (58) stamme die pasteurisasie toestande oorleef het. Uit die resultate is ’n gevolgtrekking gemaak dat die "pot" pasteurisasie metode nie effektief was nie. Daar word dus aanbeveel dat die vervaardiger die verhittings-kwaliteit van die "pot" pasteurisasie apparaat verbeter. Aangesien net die B. cereus (S4) stam al drie pasteurisasie metodes oorleef het, moet toekomstige navorsing gedoen word om die vernietigings temperatuur van dié hittebestande stam te bepaal. Die navorsing is van belang weens die behoeftes om alle bederf mikroorganismes wat tot die agteruitgang van voedsel produkte kan lei, te vernietig.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to develop new methods for pasteurization of sausages with the use of ultrasound and microwaves in order to reduce the bacterial load with more energy efficient and low impact on the characteristics of the product. For pasteurization with microwave oven, sausages were divided into 22 groups, of which one was the control that not received treatment, and the others received treatment in a microwave in different conditions, varying the time and power. The effect of the microwave treated sausage was evaluated with and without a water bath, in the presence or absence of packaging. Sausages treated with microwave unwrapped in conditions that do not change visually, reduced mesophilic and acid lactic bacteria statistically significant, but at a rate not significant for practical use. When treated were packaged, it was observed that the packaging commonly used in sausage has little resistance to microwave pasteurization, and breaks observed in some cases. It was necessary to use a water bath to maintain maintain package integrity. The data obtained on the sausage pasteurization with microwave suggest that are required the development of suitable packaging and adapting the machine to produce more uniform heating and controlled. For pasteurization with ultrasound were analyzed the effectiveness of the frequencies of 25 kHz and 130 kHz in the reduction of mesophilic bacteria and acid lactic bacteria and the effect of frequency on color, lipid oxidation and pH. We evaluated the potential bactericidal effect of ultrasound of 25 kHz on pathogenic bacteria Staphylococcus aureus and Bacillus cereus and the effect of storage on the microbiological aspects, lipid oxidation, color, pH and texture of pasteurized sausages with ultrasound. The frequency of 25 kHz, was more effective in reducing mesophilic bacteria and acid lactic bacteria and not changing color and pH, as well as producing lower lipid oxidation. The ultrasound effect was observed on the destruction of Bacillus cereus and apparently did not affect the cells of Staphylococcus aureus. For the avaluated storage conditions, ultrasound promoted inhibition of acid lactic, psychrotrophic and mesophilic bacteria and lower lipid oxidation up to 60 days of storage, with minimal color and pH change, without affecting the texture. / Este trabalho buscou desenvolver novas metodologias para a pasteurização de salsichas com o uso de ultrassom e micro-ondas com o objetivo de reduzir a carga bacteriana com mais eficiência energética e com baixo impacto sobre as características do produto. Para a pasteurização com micro-ondas as salsichas foram divididas aleatoriamente em 22 grupos, dos quais um foi o controle, que não recebeu nenhum tratamento, e os demais receberam tratamentos em micro-ondas em diferentes condições, variando tempo e potência. O efeito das micro-ondas foi avaliado em salsichas tratadas com e sem banho-maria, na presença e na ausência de embalagem. Salsichas tratadas com micro-ondas fora da embalagem em condições que não as alteraram visualmente apresentaram redução de bactérias láticas e mesófilas estatisticamente significativa, porém em taxa pouco expressiva para a utilização prática. Quando foram tratadas embaladas, foi observado que a embalagem comumente utilizada em salsichas tem pouca resistência para a pasteurização em micro-ondas, sendo observados rompimentos em alguns casos. Foi necessário utilizar banho-maria para preservar e manter a integridade das embalagens. Os dados obtidos sobre a pasteurização de salsicha com micro-ondas sugerem que é necessário o desenvolvimento de embalagens adequadas e a adaptação dos equipamentos para um aquecimento mais uniforme e controlado. Para a pasteurização com ultrassom analisou-se a efetividade das frequências de 25 kHz e 130 kHz na redução de bactérias láticas e mesófilas e o efeito das frequências sobre a cor, oxidação lipídica e pH. Avaliou-se também o potencial bactericida do ultrassom de 25 kHz frente às bactérias patogênicas Staphilococcus aureus e Bacillus cereus e o efeito do armazenamento sobre os aspectos microbiológicos, oxidação lipídica, cor, pH e textura das salsichas pasteurizadas com ultrassom. A frequência de 25 kHz, foi a mais eficiente na redução de bactérias láticas e mesófilas sem alterar cor e pH, além de produzir menor oxidação lipídica. O ultrassom teve efeito sobre a destruição de Bacillus cereus e, aparentemente, não afetou as células de Staphylococcus aureus. Nas condições de armazenamento avaliadas, o ultrassom promoveu inibição do crescimento de bactérias láticas, mesófilas e psicrotróficas e menor oxidação lipídica até 60 dias de armazenagem, apresentando pouca alteração de cor e pH sem afetar a textura.

Orientador: Luiz Francisco Prata / Banca: Angela Cleusa de Fatima Banzatto de Carvalho / Banca: Sandra Ferreira Fukuda / Resumo: Este trabalho buscou definir e padronizar uma metodologia simples e rápida para ser utilizada na indicação da segurança de consumo de leite pasteurizado. Foram analisadas 261 amostras de leite recém-pasteurizado de diferentes marcas comerciais, as quais foram submetidas à prova rápida de redução em tubos, aos métodos microbiológicos oficiais de controle (contagem padrão em placas de mesófilos, determinação do número mais provável (NMP) de coliformes totais e fecais) e às pesquisas de atividade enzimática (peroxidase e fosfatase alcalina). Padronizou-se a prova rápida em tubos partindo de diluições decimais das amostras, misturando-as ao Cloreto de Trifeniltetrazólio (TTC) e a um meio nutritivo à base de leite desnatado. As leituras foram realizadas a cada 30 minutos até completar 8 horas de incubação, observando-se a formação de cor pela redução do TTC. Comparou-se os resultados da prova rápida com os da contagem padrão em placas de mesófilos e com o NMP de coliformes (total e fecal), demonstrando uma elevada correlação linear (r = -0,85). A maioria das amostras que se encontrava fora dos padrÕes regulamentares tinha peroxidase positiva classificadas como reações P++ e P+++. Do total, 134 amostras (51,3%) foram consideradas dentro dos padrões regulamentares para ambos os métodos microbiológicos oficiais, embora oito dessas tenham reduzido o TTC em até 8 horas. Dentre as 127 amostras (49,7%) que estavam fora dos padrões regulamentares, 93 reduziram o TTC em até 8 horas de leitura... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this study was to define and to standardize a sim pie and rapid methodology to be used in the indication of the security of pasteurized milk consumption. In this work, 261 fresh-pasteurized milk samples, of different commercial brands, were submitted to a rapid test of reduction in tubes and to the official microbiological methods of control (standard plate count of mesophilic aerobic bacteria, determination of the most probable number (MPN) of total and fecal coliforms) and to the research of enzymatic activity (peroxidase and alkaline phosphatase). It was standardized rapid test in tubes leaving of decimal dilutions of the samples, mixing them it the Triphenyltetrazolium Chloride (TTC) and to a nutritional medium containing skimmed milk. The readings were realized to each 30 minutes until completing 8 hours of incubation, observing themselves it formation of color for the reduction of the TTC. The results of the fast test were compared with the ones of the standard plate count of mesophilic and with the MPN of coliforms (total and fecal), demonstrating a high degree of linear correlation (r = -0,85). Most of the samples that was found outside of established pattern had peroxidase positive as reactions P++ and P+++. Of the total, 134 samples (51.3%) were considered inside of the established limits for both the official microbiological methods, even so eight of these have reduced the TTC in up to 8 hours. Amongst the 127 samples (49.7%) that were over the established pattern, 93 had reduced the TTC in up to 8 hours of reading. The fast reduction test in tubes was able to detect bacterial counts loading from 104 UFC/mL of tested sample, with 72,2%... (Complete abstract click electronic access below) / Mestre

SILVA, Ana Irene Martins da. Beneficiamento de carne de caranguejo e avaliação de parâmetros de qualidade.2010. 69 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia de Pesca, Fortaleza-CE, 2010 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-08T16:03:46Z No. of bitstreams: 1 2010_dis_aimsilva.pdf: 10924072 bytes, checksum: 9e1c2fe6c435c23bc0f798b5b64bf33f (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-08T16:04:05Z (GMT) No. of bitstreams: 1 2010_dis_aimsilva.pdf: 10924072 bytes, checksum: 9e1c2fe6c435c23bc0f798b5b64bf33f (MD5) / Made available in DSpace on 2016-07-08T16:04:05Z (GMT). No. of bitstreams: 1 2010_dis_aimsilva.pdf: 10924072 bytes, checksum: 9e1c2fe6c435c23bc0f798b5b64bf33f (MD5) Previous issue date: 2010 / The mangrove crab (Ucides cordatus) is an important resource of mangroves which occurs in almost all in the Brazilian coast and it is notable for its considerable commercial value. The meat is usually wrapped in plastic wrap and its treatment is in a handmade way, in places where are not licensed by the Federal Inspection Service (SIF) and without the minimum hygienic control. In these places the animal’s death, done by hand, contributes to a possible contamination of the meat. In this experiment were analized 50 crabs purchased live in the outdoor market in Fortaleza, Ceara which were used during the six months of the experiment, two monthly samples. This work intends to benefit the crab meat according to Good Manufacturing Practices (GMP), using two other methods of processing: heat shock (CT) and electric shock to the system of restraint and killed by electric shock (SIAC). This machine paralyzes the animal with the application of electric pulses with controlled force and time. Thus it was evaluated the yields of meat extracted with both methods of slaughter and loss of weight due to cooking. The total average yield according to the method of slaughter, each month of the experiment, presented in percentage terms the following values respectively: CT - animal fresh weight 25.34, 23.28, 24.63, 25.38, 26, 29, 26.19% CT - 27.18 animal cooked weight, 24.81, 26.32, 26.99, 27.81, 27.74%, SIAC - animal fresh weight 26.56, 26.01 , 26.32, 25.77, 27.54, 26.97% and SIAC - animal cooked weight 28.35, 27.77, 27.69, 27.19, 28.95, 28.21%. In relation to average yields of meat extracted from the three segments pereiopod (PP), forceps or chelae (PQ) and carapace (C) separately crabs killed on the machine SIAC showed significant differences in yield of meat obtained from the segment PQ which may have favored its best performance in relation to slaughter CT, did not lose their legs during cooking which sometimes occurred with CT slaughter. Finally, the mean weight loss by cooking according to the methods of slaughter during the experiment showed similar, respectively CT - 6.68, 6.20, 6.32, 5.94, 5.38, 5.97% and SIAC - 5.26, 5.29, 4.97, 5.22, 4.91, 4.43% without no significant difference between the methods of slaughter, a phenomenon probably caused by the standardization process. / O caranguejo uçá é um importante habitante dos manguezais que ocorre em quase todo o litoral brasileiro destacando-se pelo seu considerável valor comercial. A carne é geralmente embalada em envoltório plástico e seu beneficiamento é realizado muitas vezes de forma artesanal em locais não licenciados pelo Serviço de Inspeção Federal - SIF, sendo preparado sem o mínimo controle higiênico. No beneficiamento seguido por estes locais, antes do cozimento para retirada da carne, o abdômen do caranguejo é torcido com força ou perfurado com objeto cortante, manualmente, para provocar a morte do animal, contribuindo para uma possível contaminação no local onde foi traumatizado. Foram utilizadas, durante os seis meses de experimento, duas amostras mensais de 50 caranguejos uçá, adquiridos vivos, comercializados ao ar livre em Fortaleza-Ceará. Neste trabalho pretende-se beneficiar a carne de caranguejo de acordo com as Boas Práticas de Fabricação (BPF), utilizando dois outros métodos de abate: choque térmico (CT) e choque elétrico com o Sistema de Imobilização e abate por choque elétrico (SIAC). Esta máquina paralisa os animais com a aplicação de pulsos elétricos com controle de força e tempo. Assim avaliou-se os rendimentos da carne extraída com os dois métodos de abate e a perda de peso por cocção. Os rendimentos médios totais de acordo com método de abate, em cada mês do experimento, em termos percentuais apresentaram os seguintes valores respectivamente: CT - Peso animal in natura 25,34; 23,28; 24,63; 25,38; 26,29; 26,19 %, CT - Peso animal cozido 27,18; 24,81; 26,32; 26,99; 27,81; 27,74%, SIAC - Peso animal in natura 26,56; 26,01; 26,32; 25,77; 27,54; 26,97% e SIAC - Peso animal cozido 28,35; 27,77; 27,69; 27,19; 28,95; 28,21%. Em relação aos rendimentos médios da carne extraída dos três segmentos pereódos (PP), pinças ou quelas (PQ) e cefalotorax (C) separadamente os caranguejos abatidos na máquina SIAC apresentaram diferenças significativas no rendimento da carne extraída do segmento PQ o que pode ter favorecido seu melhor rendimento em relação ao abate CT, também não soltaram as patas durante o cozimento o que ocorreu algumas vezes com abate CT. Já a média de perda de peso por cocção de acordo com os métodos de abate durante o experimento apresentou valores próximos, respectivamente CT - 6,68; 6,20; 6,32; 5,94; 5,38; 5,97% e SIAC – 5,26; 5,29; 4,97; 5,22; 4,91; 4,43% não apresentando diferenças significativas entre os métodos de abate, fenômeno causado provavelmente pela padronização do processo.

Atualmente na indústria alimentícia é comum a efetivação do processo de pasteurização em túneis, onde um fluido, geralmente água, é utilizado para transferir para o produto a energia térmica necessária. Por causa disso, um dos fatores importantes deste procedimento é a maneira como este fluido é aspergido por sobre o produto a ser pasteurizado. Existem diversas maneiras de fazer esta aspersão, cada uma com as suas características e eficiência no que diz respeito à transferência de energia no processo de pasteurização. O objetivo deste trabalho é avaliar diferentes modelos de esguichos utilizados em túneis de pasteurização de cerveja. Para isso é montada uma bancada para a realização ensaios que avaliem uma das etapas do processo de pasteurização da cerveja, onde são instalados os exemplares dos esguichos e uma garrafa de 600 ml de cerveja instrumentada. Todos os testes são realizados com os mesmos parâmetros (vazão e temperatura do fluido), somente alternando os modelos de esguichos. Usa-se a ANOVA para a comparação dos tempos de aquecimento do fluido interno e calcula-se o número de Nusselt para a convecção interna na garrafa para a avaliação dos esguichos. O resultado encontrado mostra uma independência do desempenho do processo de aquecimento em relação à alteração de modelo de esguicho para três dos quatro modelos avaliados e o último apresenta um desempenho pior. / Nowadays, in the food industry, it is usual to carry out the pasteurization process in pasteurization tunnels, where a fluid, generally water, is used to transfer the required thermal energy to the product. Because of this, one of the most important aspects of this procedure is how the fluid is sprinkled on the product that needs to be pasteurized. There are many ways to do this, each one has its own characteristics and efficiency regarding the energy transfer to the pasteurization process. The objective of this work is to evaluate distinct spray models that are used in pasteurization tunnels for beer. For this, a workbench is built to carry out experiences that evaluate one of the stages of the beer pasteurization process, where spray models are installed and an instrumented 600 ml bottle beer is used. All the tests are performed using the same specifications (flow rate and fluid temperature), just varying the spray models. ANOVA, to compare the heating times of the internal fluid, and the Nusselt number of the internal convection are used for the sprays evaluation. The result shows the independence of the performance with regard to the change of the spray model for three of the four tested models and the latter shows a worse performance.

The natural water inside green coconuts is regarded as a healthy drink due to the elements of nutritional and therapeutic value. Since there is chance of contamination of tender coconut water (TCW) with psychrophilic microbes during extraction from its hard shell if stored at 4 ºC, thermal pasteurization is currently practiced. However, the thermal treatment of TCW causes a rise in off flavors and loss of the vital nutrients. To solve this problem, a non-thermal pasteurization technology is desirable. The goal of this research was to assess the antimicrobial effectiveness of ultraviolet light C (UVC) as non-thermal pasteurization of TCW and evaluation of physico-chemical and sensory quality of the treated TCW in comparison to the fresh TCW. A dean flow ultraviolet reactor was used with wavelength of 254 nm at the residence time of 14.0 seconds. The independent variables were three Reynold numbers (Re1 = 198.8, Re2 = 397.7 and Re3 =596.4) and two different diameters of transparent PFA tubes (3.2 mm and 1.6 mm). TCW was inoculated with cultures of Escherichia coli and Listeria monocytogenes separately up to 8 log10 CFU/mL and inactivation by cold pasteurization was evaluated with number of log reduction of each bacteria. Physico-chemical properties like total solid content (TSS) and pH were analyzed throughout the storage period of four weeks. The sensorial quality, flavor and color of the coconut water was also evaluated by a panel of 30 people to compare the organoleptic characteristics of UVC treated samples with untreated fresh coconut water. In case of Escherichia coli W1485, UVC treatment gave the log reduction of 5.27 and 4.74 log10 CFU/mL in coconut water for 1.6 mm and 3.2 mm ID reactors, respectively. Whereas the reduction of Listeria monocytogenes were 4.18 and 2.96 log10 CFU/mL for 1.6 mm and 3.2 mm ID reactors, respectively. In case of both the bacteria, as the tube size increased, microbial reduction decreased; and as the Reynold number increased, microbial reduction also increased except where there was an interaction effect. The change of tube diameters gave significantly different inactivation for both test bacteria at all Reynolds number except at Re2 and Re3 in case of Escherichia coli. The different levels of Reynolds number were not significantly variant when compared with consecutive levels, but Re1 to Re3 were significantly different for both test bacteria. The physico-chemical and sensorial changes of cold pasteurized TCW weres not significantly different compared to the fresh TCW, providing the conformity of retention of natural and organoleptic characteristics of TCW.

Made available in DSpace on 2014-06-11T19:31:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-12-17Bitstream added on 2014-06-13T20:42:04Z : No. of bitstreams: 1 gumerato_hf_dr_botfca.pdf: 735190 bytes, checksum: f1454b535f3ff650b6cf9e96b355f222 (MD5) / Universidade Estadual Paulista (UNESP) / Foi estudado processo de transferência de calor transiente por agitação intermitente em embalagens, visando a conservação de alimentos por tratamento térmico com processo mais econômico e que mantivesse a qualidade de alimentícios. Objetivou-se o desenvolvimento de um processo baseado em agitação intermitente de embalagens para aplicação em pasteurização ou esterilização. O estudo da transferência de calor transiente em sistema com movimento linear alternado foi realizado em embalagens metálicas, em 4 meios simulantes de diferentes viscosidades e massas específicas: 3 óleos orgânicos e água. Foram combinados efeitos de 5 tratamentos, sendo: meio simulante (4 níveis), espaços livres (3 níveis), freqüência de agitação (4 níveis), amplitude de agitação (2 níveis) e posições das latas (4 níveis). Os ensaios de aquecimento e resfriamento foram feitos em tanque com água a temperatura de 98°C e 17 a 20°C, respectivamente. Com os dados de penetração de calor em cada experimento foram calculados os parâmetros de penetração de calor fh, jh, fc e jc. Os resultados foram modelados utilizando-se grupos de números adimensionais e foram expressos em Nusselt, Prandtl, Reynolds e... / Transient heat transfer was studied by intermittent shake in cans with linear system, in order to preserve food by heat thermally processed, applying process more economic, and keeping high food quality. The objective was developing a process based on intermittent shake in cans to applying in pasteurisation or sterilisation process. Heat transfer was carried out in metallic cans filled four different simulate medium: water, Neutral oil 150 and 500 and Bright stock oil. It was arranged five treatments: simulate media (4 levels), head space (3 levels), agitation frequency (4 levels), length of agitation (2 levels) and cans positions (4 levels). The tests were carried out in hot water tank at temperature 98°C and cool at 17~20°C. Heat transfer parameters (fh, jh, fc and jc) for each test was calculated. Results were expressed applying dimensionless numbers equations for heat and cool. Data were computed pplying dimensionless numbers and were assign as Nusselt, Prandtl, Reynolds and trigonometric functions. Results obtained from linear shake system were compared with end-over-end agitation, and shake linear system showed more efficient. Shake linear system can be applied in pasteurisation or static retorts with simple internal structure fits...(Complete abstract, click electronic access below)

Atualmente na indústria alimentícia é comum a efetivação do processo de pasteurização em túneis, onde um fluido, geralmente água, é utilizado para transferir para o produto a energia térmica necessária. Por causa disso, um dos fatores importantes deste procedimento é a maneira como este fluido é aspergido por sobre o produto a ser pasteurizado. Existem diversas maneiras de fazer esta aspersão, cada uma com as suas características e eficiência no que diz respeito à transferência de energia no processo de pasteurização. O objetivo deste trabalho é avaliar diferentes modelos de esguichos utilizados em túneis de pasteurização de cerveja. Para isso é montada uma bancada para a realização ensaios que avaliem uma das etapas do processo de pasteurização da cerveja, onde são instalados os exemplares dos esguichos e uma garrafa de 600 ml de cerveja instrumentada. Todos os testes são realizados com os mesmos parâmetros (vazão e temperatura do fluido), somente alternando os modelos de esguichos. Usa-se a ANOVA para a comparação dos tempos de aquecimento do fluido interno e calcula-se o número de Nusselt para a convecção interna na garrafa para a avaliação dos esguichos. O resultado encontrado mostra uma independência do desempenho do processo de aquecimento em relação à alteração de modelo de esguicho para três dos quatro modelos avaliados e o último apresenta um desempenho pior. / Nowadays, in the food industry, it is usual to carry out the pasteurization process in pasteurization tunnels, where a fluid, generally water, is used to transfer the required thermal energy to the product. Because of this, one of the most important aspects of this procedure is how the fluid is sprinkled on the product that needs to be pasteurized. There are many ways to do this, each one has its own characteristics and efficiency regarding the energy transfer to the pasteurization process. The objective of this work is to evaluate distinct spray models that are used in pasteurization tunnels for beer. For this, a workbench is built to carry out experiences that evaluate one of the stages of the beer pasteurization process, where spray models are installed and an instrumented 600 ml bottle beer is used. All the tests are performed using the same specifications (flow rate and fluid temperature), just varying the spray models. ANOVA, to compare the heating times of the internal fluid, and the Nusselt number of the internal convection are used for the sprays evaluation. The result shows the independence of the performance with regard to the change of the spray model for three of the four tested models and the latter shows a worse performance.