Dissertations / Theses on the topic 'Whey ultrafiltration'

Statistically designed experiments were conducted on a bench-scale ultrafiltration (UF) system using 10 kDa and 100 kDa polyethersulphone membranes to study the effect of operating conditions on membrane performance during whey processing. Experiments have underlined the importance of and provided a deeper understanding of factors influencing rejection. During filtration, a dynamic layer controlled protein fouling, reducing the effective molecular weight cut-off of the 100 kDa membrane and resulting in partial rejection. As pressure increases, the cake becomes denser allowing fewer and smaller passages for permeation, thereby increasing rejection of smaller solutes. Whey should be processed at high UF cross-flow velocities, relatively low transmembrane pressures, low feed concentrations and low temperatures. Low pressures help improve fractionation efficiency; high cross-flow velocities limit cake build-up and control cake thickness, thereby reducing specific cake resistance. Temperatures less than 10??C and pH values away from the protein iso-electric point inhibit bacterial growth and are compatible with protein, mineral and membrane stability. An existing model of dairy UF plants enabled determination of factors that affect membrane age and operational measures that minimise the effect of ageing. No significant effect of ageing was observed on performance at different volume concentration ratios (VCR). Operation at VCR 37 and 38 was capable of producing 80% whey protein concentrate (WPC). The effect of diafiltration water is improved when introduced over two loops with reallocation. Prevention of reallocation will dilute the total solids concentration in the retentate producing product that is out of specification. High protein rejections, lactose and ash rejection values between 5-15%, and non-protein nitrogen rejections below 50% are essential for producing 80% WPC. Fat rejection did not influence product quality although experimental studies show that fat concentration in liquid whey affects performance. Flux was the most influential measure of membrane life. Membrane elements in loops 11-12 did not require as frequent replacement compared to elements in loops 5-7 which are most susceptible to ageing. Emphasis should be placed on these elements for cleaning routines and operating conditions that minimise the effects of fouling in order to produce 80% WPC.

Doutoramento em Engenharia Agro-Industrial - Instituto Superior de Agronomia
In this thesis we studied the efficiency of fractionation of ovine whey by ultrafiltration followed by nanofiltration, in terms of permeation fluxes and apparent rejections. The application possibilities of the concentrates produced were also investigated. Ultrafiltration tests were performed in total recirculation mode under different operating conditions of transmembrane pressure and feed recirculation velocity with membranes ETNA10PP, GR81PP and GR61PP. The membranes ETNA10PP turned out to be the most appropriate for the separation of the whey protein fraction because they allowed higher permeate flux (higher productivity) with apparent rejections coefficients of the protein above 90% and low apparent rejections of lactose, providing a better separation between the two fractions (protein and fraction rich in lactose). So, the membranes ETNA10PP were used in the trials of ultrafiltration, in concentration mode, till a volume concentration factor (VCF) of 4.0. Samples of concentrates were taken for the VCF´s of 1.8, 2.0, 3.0 and 4.0, which were used to manufacture cheese whey, following the traditional process of production. Compared to traditional whey cheese, the curd made from protein concentrates have dried residues, ash and fat contents significantly lower than those determined in traditional whey cheese, whereas concentrations of protein and lactose and the hardness are significantly higher. The nanofiltration of ultrafiltration permeates, performed with membranes NFT50, allowed almost total recovery of lactose and organic matter, measured by chemical oxygen demand. The diafiltration of the lactose concentrates can be used for purposes of purification, according to the intended end application.

Membrane processes have found increasing industrial applications worldwide. For membrane processes to deliver their desired performances and mitigate the effect of disturbances, automatic controllers must be installed. Before the installation of controllers, operability analysis is a crucial step to evaluate how well the processes can be controlled, and to determine how process design can be improved for better control. However, existing applications of operability analysis in membrane processes are limited. This thesis extends the application of operability analysis to a multiple-stage membrane process, exemplified by a detailed case study of a 12-stage industrial whey ultrafiltration (UF) process. Process dynamic models are determined to describe the transient behaviour of process performance caused by disturbances and long-term fouling. Steady-state nonlinear operability analysis is conducted to identify inherent limitations of the process. Using the process dynamic models, dynamic operability analysis is performed to determine the effects of dynamic behaviour on process and controller design. Steady-state operability analysis shows that the whey UF process is not able to mitigate the effects of high concentrations of true protein in the fresh whey feed. The ability of the process to mitigate the effects of disturbances is also adversely affected by long-term membrane fouling. Mid-run washing is therefore necessary to restore control performance after long periods of operation. Besides demonstrating the adverse effects of long-term membrane fouling on operability, dynamic operability analysis identifies the manipulated variables that can deliver the best control performance. It also indicates that control performance can be improved by installing equipment (e.g. buffer tanks) upstream of the process. Dynamic operability analysis shows that recycling of the retentate stream has a profound effect on the plant-wide dynamics and reduces significantly the achievable speed of process response under automatic control. However, retentate recycling is essential during operation to minimize membrane fouling. Although reducing the number of stages in the whey UF process can improve the achievable speed of process response under automatic control, process performance will fluctuate significantly from its desired level. A trade-off therefore exists between process performance and control performance that should be addressed during process and controller design.

Orientador : Luiz Antonio Viotto
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Estudos de pré-tratamentos do soro que melhorem a taxa de permeação em processos por membranas de ultrafiltração (UF) são importantes para a viabilização econômica da produção de concentrados protéicos de soro (CPS). Além disso, os pré-tratamentos também podem ser utilizados no melhoramento das propriedades funcionais das proteínas do soro. No entanto, este processo de concentração apresenta uma dificuldade natural durante a DF do soro conhecido como "fouling", ou entupimento das membranas, a qual constitui o ¿principal¿ problema do uso desta tecnología nas indústrias de laticínios; uma vez que causa uma alta redução no fluxo de permeado. O objetivo deste trabalho foi estudar o efeito de pré-tratamentos do soro; microfiltração, ajuste de pH e tratamento térmico, bem como a influência dos parâmetros operacionais de vazão volumétrica e pressão transmembrana no fluxo do permeado durante a ultrafiltração. Amostras de alimentação, do retentado e do permeado das etapas de microfiltração e ultrafiltração foram tomadas para análise de composição química (conteúdo protéico, gordura, nitrogênio total e cinzas). O soro, obtido da produção de queijo Minas Frescal, foi submetido a dois tipos de pré-tratamentos; ajuste do pH 7,3 antes do tratamento térmico a 55°C por 15 minutos, seguido de microfiltração numa membrana cerâmica (alumina), com diâmetro médio de poro de 1,4 f..lm e área de permeação de 0,24 m2, em condições operacionais fixas de 4,3 m3 fh de vazão volumétrica, pressão transmembrana de 0,5 bar e temperatura operacional constante de 50°C. O permeado da microfiltração foi ultrafiltrado em uma membrana de polisulfona, tipo Fibra Oca da Koch Membrane, com massa molecular de corte de 10000 Da, área de permeação de 1,3 m2. A temperatura desta etapa foi fixada em 50°C, variandose a pressão transmembrana de 0,5 a 2 bar e a vazão volumétrica de 1,8 a 3,6m3fh até fator de concentração (FC) 15, resultando em concentrados protéicos de soro (CPS) com cerca de 70% de proteína total, em base seca. Foi possível verificar, através da análise estatística, QS efeitos significativos da pressão transmembrana e da vazão volumétrica sobre o fluxo de permeado nas faixas estudadas. O fluxo médio máximo de 53,77 kg/m2.h foi 9btido a uma vazão de 3,6 m3fh a 2 bar de pressão. O efeito das variáveis independentes não foi significativo no rendimento protéico que assumiu valores de 0,98 e 0,99, demonstrando que este valor é característico da interação entre a membrana e produto, e não depende dos parâmetros do processo. Foi possível verificar ainda que, com o aumento da vazão volumétrica e da alta pressão transmembrana nas faixas estudadas, houve um aumento da relação entre proteína e lactose (Pt/Lact) a FC 15 em relação à alimentação; sendo que a 3,6m3fh e pressão transmembrana de 2 bar, a relação Pt/Lact assumiu o mais alto valor (3610,89). O modelo de Kuo & Cheryan (1983) para as condições de pressão transmembrana de 0,7-2 bar, vazão volumétrica de 1,8-3,6 m3fh e a temperatura de 50° C apresentou melhor concordância com os dados experimentais do que o modelo de Wu et aI. (1991)
Abstract: Pre-treatments of whey to improve the permeate flux in ultra filtration (UF) membrane processes are important for economic viability of whey protein concentrate (WPC) production. Moreover, pre-treatments can also be used to improve functional properties of whey proteins. Nevertheless, membrane fouling is the main technological problem concerned to dairy industries due to the permeate flux reduction during UF processo The goal of this work was to study the influence of pre-treatments like micro filtration (MF), pH adjustment and heat treatment, as well as operational parameters like volumetric flow and transmembrane pressure on ultra filtration permeate fluxo Samples of feed, retentate and permeate at CF 11,5 and 15 were analyzed for chemical composition (protein content, lipids, total nitrogen and ash), on MF and UF steeps, respectively. Sweet whey from Minas Frescal cheese was submitted at two pre-treatments: a combination of pH adjustment and heat treatment followed by micro filtration. Initially, pH was adjusted to 7,3 and heated at 55°C for 15 minutes. After it, the whey was micr filtrated in a ceramic membrane (Alumina), with an average diameter pore of 1,4 _ and permeation area of 0,24 m2. The volumetric flow was maintained constant at 4,3 m3fh, transmembrane pressure at 0,5 bar and temperature at 50°C. The permeate of MF step was then ultra filtered in a polissulfone membrane Hollow Fiber (Koch Membrane), MW lOkDa, with 1,3m2 of permeation effective area at constant temperature at 50°C. The transmembrane pressure varied between 0,5 and 2 bars and flow from 1,8 to 3,6m3fh until a concentration factor (CF) of 15. The WPC produced contain about 70% of total protein, in dry basis. It was observed, by statistical analysis, that transmembrane pressure and volumetric flow had a significant effect on permeate flux in the range value of parameters studied. Maximum flux (53,77 Kg/m2.h) was found with volumetric flow of3,6 m3fh and 2 bars of pressure. Protein yield (with values between 0,98 and 0,99) was not significantly affected by these parameters, which demonstrate that the interaction between the membrane and the product does not depend of there parameters. It was also observed that, with the increase of volumetric flow and the transmembrane pressure resulted, an increase in the percentage of variation of relation protein and lactose (PtlLact) at CF 15 relatively the feed. The maximum value (3610,89%) was obtained at the same condition of the best permate flux Kuo & Cheryan (1983) model showed better agreement to experimental data than Wu et aI. (1991) model, for all combinations of transmembrane pressure and volumetric flow at temperature of 50° C
Mestrado
Mestre em Engenharia de Alimentos

Orientador: Salvador Massaguer Roig
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Este trabalho constitui em desenvolver tecnologia de fabricação de requeijão cremoso utilizando concentrado oretéico de soro ultrafiltrado e estudar as caracteristicas fisico-quimicas, de textura instrumental e sensorial, capacidade de derretimento de queijo, propriedades reológicas e de caracterização sensorial dos produtos. A fabricação dos produtos foi realizada nas instalações da Indústria de Laticínios Bombardelli em condições de processo industrial. Na 1ª etapa foram realizados dois experimentos. O primeiro experimento avaliou a possibilidade do aproveitamento do concentrado protéicode soro (CPS), de massa coagulada com e sem lavagem da massa, e de utilização de diferentes fontes de gordura, como o creme de leite e a manteiga, na fabricação de requeijão cremoso. O segundo experimento avaliou pontos tecnológicos de processo de ovbtenção dos ingredientes de fabricação sos requeijões cremosos. Na 2ª etapa também foram realizados dois experimentos. O primeiro experimento consistiu na fabricação dos requeijões cremosos utilizando quatro níveis de CPS (6,8, 10 e 12%) e três níveis de gordura no extrato seco (GES) (55, 60e 65%). Foram avaliadas as caracteristicas fisico-quimicas dos ingredientes e, o fluxo de requeijão e os parâmetros de textura industrial dos produytos. Os produtos fabricados foram comparados com requeijões comerciais. No segundo experimento foram utilizados cinco níveis de CPS (0, 6, 8, 10 e 12%) e três níveis de GES (55, 60, e 65%). Ocorreram diferenças significativas (p<0,05) entre as amostras de requeijão cremosos, em relação aos parâmetros de textura instrumental e teste de derretimento. A 3ª etapa consistiu de um experimento que permitiu a realização do estudo de análise sensorial que incluiu o teste de aceitação a Análise Descritiva Quantitativa (ADQ) realizada por uma equipe sensorial de onze provadores. Foram avaliadas 15 amostras de requeijão cremoso fabricadas com a adição de cinco níveis de concentrado protéico de soro e três níveis de sal emulsificante e quatro amostras comerciais de requeijão. Foram escolhidas pelo teste de aceitação as quatro melhores amostras de requeijão com CPS e uma amostra de requeijão comercial, considerando a aparência, aroma, sabor, consistência e espalhabilidade. Baseado nestes resultados, as cinco melhores amostras foram realizadas por meio de análise descritiva quantitativa, caracterizando os produtos, Foi avaliada a realção que existe entre as caracteristicas fisico-quimica com a capacidade de derretimento e parametros de textura instrumental (TPA) dos requeijões cremosos. A 4ª e ultima etapa consistiu de um experimento, em que se avaliou o efeito das variáveis de processo, pela incorporação de diferentes níveis de concentrado protéico de soro obtido por ultrafiltração de sal emulsificante sobre as respostas de textura instrumental e sensorial. O planejamento experimental consistiu de quatro ensaios, quatro pontos centrais, totalizando 12 ensaios. Obteve-se faixas ótimas de uso de CPS e SE que proporcionaram as melhores respostas sensoriais de cremosidade, pastosidadee espalhabilidade e de textura instrumental de dureza, adesividade, elasticidade e gomosidade. Obteve-se um índice reológico de comportamento (n) mínimo n = 0,51 para amostra 07 (produto mais viscoso) e máximo n = 0,80 para amostra 08 (produto menos viscoso)
Abstract: This work consisted to develop technology of manufacture of requeijão cremoso utilizing whey protein concentrate ultrafiltered and study the chemicalphysical characteristics, sensory and instrumental texture, melting cheese capacity, rheological properties and sensorial characteristics of products. The fabrication of products was realized in Bombardelli Dairy Industry in conditions insdustrial process. In the first stage, were realized two experiments. The first experiment evaluated the possibility of to use whey protein concentrate, soft coagulante curd with and without curd was, use of different fat sources as milk cream or butter in fabrication os requeijão cremoso. The second experiment, was realized to define the process fluxogram to be used and the operacional range of the variables to be studied. In second stage was realized two experiments again. First experiment consisted in manufactured requeijões cremosos utilizing 6, 8, 10 and 12% whey protein concentrate and three levels of fat dry matter (55, 60 and 65%) . Were evaluated chemicalphysical characteristics of the ingredients and, melting capacity and instrumental texture parameters (TPA) of products. In second experiment were utilized five levels whey protein concentrate (zero, 6, 8, 10 and 12%), and theree levels of fat dry matter (55, 60 and 65%). Ocurred significant difference (P<0,05) between samples of requeijões cremosos in relationship melting capacity and instrumental texture parameters (TPA). Third stage consisted of one experiment that permited the realization of sensory analysis, including acceptance test and Descriptive Quantitative Analysis (DQA) realized by eleven panelist judged. Were choosed by acceptance test lhe four better samples of requeijão with addition whey protein concentrate and one commercial sample of requeijão with base in appearance, flavour, tate, consistency and spreadly. Based in this results, the fivebetter samples were analised utilizing descriptive quantitative analysis, characterizing the products. Was evaluated the relationship there are between chemicalphysical characteristics and melting capacity and texture parameters (TPA) oj "requeijões cremosos". Fouth and final stage consisted also of one experiment, in that evaluated the process variables effects, by incorporation of differents levels whey protein concentrate obtained by ultrafiltration and emulsifying salt on the instrumental and sensorial texture responses. The experimental design included four assay, four axis point and four centre points, resulting in 12 experimetal runs. Obatained abtimize regions of use of whey protein concentrate and emulsifying salt that providing the better sensorial responses of cremosity, stickiness and spreadability and better instrumental textures responses of firmness, adesiviness, elasticity and gumniness. The sample seven had minimal flow rheological behaviour index (n=0,51 product more viscous) and sample eight had maximum flow rheological behaviour index (n=0,80 product lesser viscous)
Doutorado
Doutor em Tecnologia de Alimentos

A deglutição é um processo coordenado e extremamente complexo, envolvendo contração e inibição de músculos localizados entre a boca e o estômago. Alterações neste sistema podem gerar disfagia, sinal comum de diversas doenças orgânicas, alterações neurológicas ou doenças neuromusculares, produzindo no paciente dificuldade na mastigação e deglutição de alimentos. Prover deglutição segura para indivíduos disfágicos é um desafio, contudo, esta pode ser facilitada se os alimentos tiverem a textura modificada e os líquidos forem espessados. Dessa maneira, este trabalho teve por objetivo desenvolver uma formulação de espessante alimentar, com valor nutricional agregado, para espessar diferentes líquidos, tornando-os com consistência adequada para pacientes disfásicos e avaliar sua ação em diferentes líquidos, testando a influência do tempo de espessamento e temperatura, sobre a estabilidade das viscosidades obtidas com as amostras. O ingrediente base usado para formulação e fonte de proteína foi o concentrado protéico de soro de leite (WPC), obtido experimentalmente, através da utilização das tecnologias de membranas, ultrafiltração (UF) e diafiltração (DF), através de três experimentos distintos. Inicialmente, 30 litros de soro em pó reconstituído, foram concentrados através da ultrafiltração, com redução do volume para cinco litros, a partir deste volume realizaram-se as diafiltrações. No primeiro experimento executaram-se quatro DF, duas de cinco litros e duas de 2,5 litros, obtendo-se WPC-1 com 56% de proteína. No segundo experimento também com quatro DF, executaram-se dois deles com 10 litros e dois com cinco litros, obtendo-se o WPC-2, com 71% de proteína. Para o terceiro experimento, os ciclos das diafiltrações foram aumentados para seis DF de cinco litros cada, obtendo-se o WPC-3, com 80% de proteína. Os concentrados obtidos foram liofilizados e caracterizados em relação a suas propriedades funcionais, sendo a solubilidade a mais importante por estar diretamente ligada à utilização em formulações alimentares de bebidas. Obteve-se solubilidade média de 70, 77 e 85% para WPC-1, 2 e 3 respectivamente. Pelas características obtidas de concentração de proteínas e percentual de solubilidade, o concentrado protéico obtido no terceiro experimento foi o selecionado para ser utilizado na formulação. Esta ficou constituída de 68% de concentrado protéico de soro de leite, 2% de mix de vitaminas e minerais e 30% do agente espessante (goma guar). Através de testes preliminares realizados com o agente espessante, determinou-se a porção do produto formulado necessária de ser adicionada aos líquidos para que os mesmos atingissem os níveis de consistência desejados, ou seja, 4,2 g para consistência de néctar (50 – 351 cP), 6,7 g para consistência de mel (351-1750 cP) e 9,2 g para consistência de pudim (> 1750 cP), tradicionalmente recomendadas para indivíduos disfásicos, segundo o National Dysphagia Diet Guidelines (NDD). Diferentes amostras (leite, sucos de abacaxi, de uva e de laranja) foram espessadas e realizadas medidas da viscosidade aparente, expressas em centipoise (cP), nos tempos pós-preparo: 10 minutos, 2 horas com taxa de cisalhamento (“shear rate”) de 50s-1 a 25ºC. As amostras foram armazenadas sob refrigeração e após 24 horas, novas medidas foram realizadas com taxa de cisalhamento de 50s-1 a 10ºC. Houve diferença estatística significativa entre as médias de viscosidade nos tempos de preparo de todos os níveis de consistência, demonstrando que o agente espessante utilizado continuou agindo, hidratando-se e aumentando a viscosidade com o passar do tempo. Também foi encontrada diferença significativa entre algumas amostras, com diferentes líquidos de diluição, quando comparadas entre si no mesmo nível de consistência. No entanto, as amostras apresentaram viscosidade dentro dos níveis sugeridos pela National Disfagic Diet, com exceção da consistência de pudim que, no tempo 10 minutos, permaneceu abaixo dos limites, adequando-se com o tempo, para o consumo de indivíduos disfágicos.
The swallowing is a coordinated and extremely complex process, involving contractions and inhibitions of muscles located between the mouth and the stomach. Alterations on this system can generate dysphagia, common sign of several organic diseases, neurological alterations or neuromuscular diseases, producing in the patient difficulty in the mastication and Swallowing of food .To provide safe swallowing for dysphagic individuals is a challenge, however, this can be facilitated, if the food has modified texture and if the liquids are thickened. In this way, the purpose of this work was to develop a formulation of food thickener, with aggregated nutritional value, to thicken different liquid foods, giving them an appropriate consistence for dysphagic individuals and to evaluate its action in different liquid foods, testing the influence of the time of thickening and temperature, over the stability of the viscosities obtained by the samples. As ingredient base for formulation and protein source was used whey protein concentrate (WPC), obtained experimentally, through the use of the technologies of membranes, the ultrafiltration (UF) and diafiltration (DF), through three different experiments. Initially, 30 liters of reconstituted powder serum, were concentrate through ultrafiltration, with reduction of the volume for cinco liters, starting from this volume the diafiltration took place. In the first experiment quatro DF were executed, two of cinco liters and two of 2.5 liters, obtained WPC-1 with 56% of protein. In the second experiment quatro DF were executed, two of them with 10 liters and two with cinco liters, obtaining WPC-2 with 71% of protein. For the third experiment, the cycles of the diafiltration were increased for 6 DF of 5 liters each, obtaining WPC-3 with 80% of protein.The obtained concentrates were liofilized and characterized in relation to its functional properties, being the solubility the most important for being directly linked to the use in alimentary formulations and drink. Average solubility of 70, 77 and 85% were obtained for WPC, 1, 2 and 3 respectively. Due to the obtained characteristics of protein concentrate and its solubility, the WPC obtained in the third experiment was selected for if used in the formulation. This was constituted of 68% of whey protein concentrate, 2% of mix of Vitamins and Minerals and 30% of the thickning agent (gum guar). Through preliminary tests accomplished with the thickening agent the amount of formulated product necessary to reach the desired consistence levels was determined, being 4.2 g for nectar consistence (50 – 351 cP), 6.7 g for honey consistence (351-1750 cP) and 9.2 g for pudding (> 1750 cP), traditionally recommended for dysphagic individuals according to National Dysphagia Diet Guidelines (NDD). Different samples (milk, pineapple juices, and grape and orange) were thickened and measurements of apparent viscosity were carried out, expressed in centipoise (cP), in the times after preparation: 10 minutes, 2 hour with shear rate of 50s-1 to 25±2ºC. The samples were stored under refrigeration and after 24 hours, new measurements were accomplished with shear rate of 50 s-1 to 10±2ºC. There were significant statistic difference among the average viscosity in the times of preparation of all the consistence levels, demonstrating that the thickening agent used continued acting, increasing the viscosity in the course of time. As well as significant differences among some samples when compared to each other in the same consistence level, caused by the different constituents of the drinks taken as sample. However, all samples presented viscosity inside the levels suggested by National Dysphagic Diet, except for the pudding consistence that, in the time of 10 minutes, was below these limits, fitting with time, being for this inside the levels suggested, appropriated for consumption by dysphagic individuals.

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CAPES
The aim of this study was to evaluate the process of protein concentration in bovine whey proteins by ultrafiltration process and subsequently the protein hydrolysate obtained by enzymatic hydrolysis to produce bioactive peptides with potential antimicrobial and antioxidant activities. For concentration process was used a ceramic ultrafiltration membrane with a molecular range cut-off of 10-20 kDa, transmembrane pressure of 5 bar and, temperature of 30 ?C, 40 ?C and 50 ?C . The optimum temperature condition was at 40 ?C. The Volume Concentrate Factor (VCF) parameter was used as a end-point of the ultrafiltration process and fixed at 2, corresponding on concentrating the initial volume twice, in volume. At the temperature of 40 ?C, VCF had a correspondence on final protein concentration on the concentrated fraction by ultrafiltration and confirmed by Bradford method. Two commercial enzymes were tested Alcalase, Flavourzyme and an equivalent mixture of both 50:50 (w/w) in the hydrolysis reaction. The hydrolysis conditions were determined according to manufacturer instructions and confirmed by other studies: 60 ?C and pH 8 for Alcalase; 50 ?C and pH 7 for Flavourzyme; 50 ?C and pH 8 for enzyme mixture with enzyme / substrate ratio (w / w) 5/100 for all enzymes. The reaction was monitored by pH Stat method. The final Degree of Hydrolysis (DH) achieved was 15%, 52% and 63% for Flavourzyme, Alcalase and enzyme mixture, respectively. Five aliquots were collected along the hydrolysis for each enzyme reaction corresponding to differents DH in order to evaluatethe antioxidant activity by ORAC and ABTS assays with final values between 597- 1092 m? TE (ABTS) and from 1615 to 2920 ?M TE (ORAC) for Flavourzyme; 998-6290 ?M TE (ABTS) and 3092-7567 ?M TE ( ORAC) for Alcalase and finally 913-2678 ?M TE (ABTS) and 2547-5903 ?M TE (ORAC) for the enzyme mixture. The samples from all hydrolysates showed no antimicrobial activity against strains of Salmonella choleraesuis subsp. Enteritidis (ATCC 13076) and Listeria monocytogenes (ATCC 9117).
A proposta do presente trabalho foi avaliar a concentra??o das prote?nas do soro de leite bovino por ultrafiltra??o e posterior obten??o de hidrolisados proteicos deste concentrado via hidr?lise enzim?tica visando obter pept?deos bioativos com potencial atividade antimicrobiana e antioxidante. Para concentra??o das prote?nas do soro foi utilizada membrana cer?mica de ultrafiltra??o com massa molar de corte de 10-20 kDa, press?o aplicada ? membrana de 5 bar, temperaturas testadas (30 ?C, 40 ?C e 50 ?C) . A temperatura ?tima selecionada foi de 40 ?C. O Fator de Concentra??o Volum?trica foi o par?metro utilizado para indicar o final do processo de ultrafiltra??o sendo fixado em duas vezes o volume inicial da alimenta??o. Na temperatura de 40 ?C foi obtida correspond?ncia entre a concentra??o volum?trica e a concentra??o proteica final na fra??o retida pela UF, que tamb?m foi o dobro da encontrada na fra??o alimenta??o, avaliada pelo m?todo de Bradford. Foram testadas duas enzimas comerciais: Alcalase, Flavourzyme e uma mistura equivalente de ambas, na propor??o 50:50 (m/m) na rea??o de hidr?lise. As condi??es de rea??o enzim?tica foram determinadas de acordo com instru??es do fabricante e corroboradas por outros estudos em: 60 ?C, pH 8 para Alcalase; 50 ?C, pH 7 para Flavourzyme; 50 ?C, pH 8 para mistura enzim?tica e rela??o enzima/substrato (g/g) foi de 5/100 para todas as enzimas. A rea??o de hidr?lise foi monitorada pelo m?todo pH Stat. Os Graus de Hidr?lise (GH) finais alcan?ados foram de 15 %, 52 % e 63 % para Flavourzyme, mistura enzim?tica e Alcalase, respectivamente. Foram coletadas cinco al?quotas correspondentes a diferentes GH ao longo da rea??o para cada condi??o enzim?tica utilizada e avaliadas quanto a atividade antioxidante pelos m?todos ABTS e ORAC tendo valores entre 597 a 1092 ?M TE (ABTS) e 1615 a 2920 ?M TE (ORAC) para Flavourzyme, 998 a 6290 ?M TE (ABTS) e 3092 a 7567 ?M TE (ORAC) para Alcalase e por fim, 913 a 2678 ?M TE (ABTS) e 2547 a 5903 ?M TE (ORAC) para a mistura enzim?tica. Nenhuma das amostras de hidrolisado com diferentes GH apresentou atividade antimicrobiana contra cepas de Salmonella choleraesuis subsp. Enteritidis (ATCC 13076) e Listeria monocytogenes (ATCC 9117).

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A proposta deste estudo foi oferecer novas alternativas para o aproveitamento sustentável do soro desproteinado através do desenvolvimento e disponibilização de tecnologias simples de fabricação de bebidas lácteas acidificadas carbonatadas, com vida útil estendida, sem a utilização de tratamentos térmicos extremos. Foram utilizados três diferentes tipos de soros desproteinados (permeado de ultrafiltração, soro de ricota e soro ácido obtido da fabricação de queijos coagulados por acidificação direta), que normalmente são descartados pelas indústrias de laticínios. Para cada tipo de soro foram produzidas bebidas acidificadas carbonatadas em 3 repetições que foram analisadas ao longo do período de 60 dias. Verificou-se diferenças significativas entre as bebidas em relação á acidez, pH e viscosidade. Porém, para cada bebida, não houveram diferenças significativas em relação ao tempo, o que significa que permaneceram estáveis sob esses aspectos durante os 60 dias de armazenamento. Entretanto, pôde - se observar a deposição de proteínas que iniciou entre 20 e 30 dias de estocagem , em razão do pH baixo, e à perda de capacidade do estabilizante de manter essas proteínas dispersas. Os produtos apresentaram estabilidade microbiológica durante todo o tempo de estocagem sob refrigeração, não apresentando contagem de microrganismos patogênicos, confirmando assim a eficácia das barreiras microbiológicas aplicadas (pH, tratamento térmico e dióxido de carbono). As análises sensoriais demonstraram que as bebidas apresentaram boa aceitação. No entanto, a bebida produzida com soro permeado de ultrafiltração obteve maior aceitação e foi preferida em relação às demais. Ao longo do tempo de estocagem as bebidas apresentaram a mesma aceitabilidade sensorial. A bebida láctea desenvolvida pode agregar valor ao soro desproteinado permitindo o seu uso adequado e sustentável por parte das indústrias de laticínios.
The purpose of this study was to offer new alternatives for the sustainable use of unprocessed whey through the development and availability of simple technologies for the production of acidified carbonated dairy drinks with an extended shelf life without the use of extreme heat treatments. Three different types of deproteinated sera (ultrafiltration permeate, ricotta whey and acid whey obtained from the manufacture of cheeses coagulated by direct acidification) were used, which are normally discarded by the dairy industry. For each type of serum, acidified carbonated beverages were produced in 3 replicates that were analyzed over the 60 day period. There were significant differences between the beverages in relation to acidity, pH and viscosity. However, for each beverage, there were no significant differences in time, which means that they remained stable under these aspects during the 60 days of storage. However, protein deposition occurred between 20 and 30 days of storage due to the low pH and the loss of capacity of the stabilizer to keep these proteins in solution. The products presented microbiological stability during the whole storage time under refrigeration, not counting pathogenic microorganisms, thus confirming the effectiveness of the applied microbiological barriers (pH, heat treatment and carbon dioxide). Sensory analysis showed that the drinks were well accepted. However, the beverage produced with permeated ultrafiltration serum obtained greater acceptance and was preferred over the others. Throughout the time of storage the drinks presented the same sensorial acceptability. The developed dairy beverage can add value to the unprotected whey allowing its proper and sustainable use by the dairy industries.

Thesis (M.S.)--University of Wisconsin--Madison, 1988.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 109-121).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1985.
Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 366-372).

Cheddar cheese whey was concentrated using an ultrafiltration (OF) membrane with a 50 kDa molecular weight cut-off (MWCO). The concentrated whey was applied to an immobilized metal affinity chromatography (IMAC) column to isolate IgG. With a 50 ml IMAC column loaded with 17.3 ml of 50 mM CuCl₂ to get 2/3 Cu saturation, 1240 mg of IgG could be isolated with 56% purity. About 152 mg of lactoferrin and 90 mg of lactoperoxidase could be isolated along with the IgG. By using concentrated whey instead of unconcentrated whey, the time required to apply the whey was reduced proportionally to the concentration factor. Whey could be concentrated up to 30 times without any decrease in recovery or purity of IgG obtained by IMAC. UF of whey with a 50 kDa or 100 kDa MWCO membrane at 4°C or 45°C did not affect IgG recovery or purity obtained by IMAC. Diafiltration also had no effect. By using 50 mM glycine instead of 1.0 M NH₄Cl in the eluting buffer, elution was more efficient. The type of whey used could affect the recovery and purity of IgG obtained by IMAC. IMAC was run at room temperature or 7°C without any loss in recovery or purity of IgG, but the elution profile was altered. IgG could be recovered from a whey concentrated commercially by UF as well. A method was also developed to isolate IgG from raw skim milk using UF and IMAC. Ion exchange chromatography was compared to IMAC as an alternative method to isolate IgG from concentrated whey. Ion exchange chromatography gel was about 31 times less expensive than IMAC gel. The capacity of an ion exchange chromatography column for IgG was 16 times lower than for an IMAC column, and the purity of IgG recovered was lower. Taking the capacity into account, the overall cost of IMAC was about 2 times more than ion exchange chromatography. Considering the high purity of IgG obtainable and the advantages in working with smaller columns, IMAC appeared to be a better method of isolating IgG. A small-scale shelf life study of IgG in UHT milk was also done. A thermal resistance curve for IgG in UHT milk was constructed assuming first-order destruction of IgG at 62°, 66°, 70°, 74°, 78° and 80°C. D values were obtained from the first-order destruction curves. The D values were used to plot a thermal resistance curve, and D values were extrapolated for temperatures used for the shelf life study. D values extrapolated were 1.77 x 10¹⁴ yr at 4°C, 3.85 x 10⁷ yr at 25°C, and 1.94 x 10⁵ yr at 35°C. IgG isolated by IMAC was membrane sterilized using prefiltration and final filtration with a 0.2 Jim membrane. Membrane sterilization did not affect IgG activity. Membrane sterilized IgG was aseptically injected into 250 ml Tetra Brik cartons containing 2% white UHT milk. The cartons were stored at 4°, 25° and 35°C. Over 5 months of the shelf life study, no change was observed in IgG concentration as predicted.

A tryptic hydrolysis of whey protein isolate has generated 19 peptides from β-lactoglobulin source, out of 27 peptide sequences detected under HPLC-MS. Amongst 19 peptides, 12 were detected as anionic peptides and 5 as cationic peptides. The aim of this work was to investigate the process parameters for fractionating bioactive peptides from protein hydrolysate by pilot-scale electrodialysis with ultrafiltration membrane (EDUF) unit. Preliminary tests were performed to evaluate process parameters. A pressure-flow relation was studied for establishing no transmembrane pressure. Protein hydrolysate was fractionated during 60 minutes by EDUF on a pilot-scale EUR6 module. Under a constant pH of 6 and electric field strength of 0.7 V/cm, peptide migration rates of 0.57 ± 0.25!!/!!ℎ and 0.29 ± 0.09!!/!!ℎ were achieved in anionic and cationic peptides recovery compartments respectively. An experiment was also further investigated under two electric field conditions: pulsed electric field (PEF) and reverse polarity (RP) to observe the effect on migration rate and selectivity. Total migration rates were found to be 0.51 ± 0.05 and 0.38 ± 0.15 !/!!ℎ under PEF and RP conditions, respectively. An application of PEF and RP were able to separate selectively few of peptides. Peptide migration rate and selective separation of peptides found to be strongly depended on electric field strength and pressure/flow rate in each compartment. It is the low electric field and relatively higher pressure that hinders the simultaneous separation of anionic and cationic peptides in their respective compartment. To our knowledge, it was the first attempt to study separation of bioactive peptides from whey protein isolate in a pilot scale EDUF module.

Dissertação de mestrado integrado em Engenharia Biológica
O soro de queijo é um subproduto da indústria alimentar que representa um grande problema ambiental, dado que tem uma elevada carga orgânica. A sua valorização constitui uma oportunidade para a indústria alimentar devido às propriedades nutricionais e funcionais que apresenta. Atualmente, os processos membranares, como é o caso da ultrafiltração (UF), assumem um grande destaque na valorização do soro, sendo o estudo destes sistemas o principal objetivo deste trabalho. Na primeira fase deste trabalho pretendeu-se caracterizar o soro para posteriormente o testar num sistema de UF com um fator de concentração de três vezes de modo a obter concentrados proteicos do soro (CPS). No final do processo, o soro e o concentrado foram submetidos a uma eletroforese, de forma a estudar o fracionamento das proteínas presentes. Por fim, foi realizado um estudo técnico/económico de forma a perceber a viabilidade da implementação de um sistema de membranas à escala industrial. A caracterização do soro revelou ligeiras diferenças entre as várias amostras recolhidas, estando de acordo com o descrito na bibliografia consultada, exceto o teor em gordura, que aqui se revelou superior. O processo de concentração permitiu obter concentrados proteicos na ordem dos 25 % de proteína, confirmando assim a eficiência da UF. No gel de eletroforese observou-se o fracionamento das proteínas maioritárias no tamanho desejado, sendo claramente visível a maior densidade das bandas de β-lactoglobulina (β-lg) e α-lactalbumina (α-la) No estudo técnico/económico foram testadas várias alternativas para a valorização do soro com recurso a membranas. Para obtenção dos concentrados líquidos, o sistema incluía uma centrífuga e um sistema de membranas, UF ou nanofiltração (NF). Para a obtenção dos concentrados em pó foi necessária a inclusão de um equipamento de secagem. O recurso ao sistema de NF mostrou-se o mais vantajoso, obtendo-se lucros superiores, tanto para o caso em que se vende o concentrado líquido como o concentrado sólido. A implementação de um spray dryer no sistema, apesar de apresentar maiores custos iniciais e de operação, permite um maior lucro dada a valorização do produto, que é vendido diretamente em pó. Também se pode aproveitar o sistema e produzir manteiga com baixo teor em sal.
Whey is a byproduct of the food industry that represents a huge environmental problem because it has a high organic load. Its valorization is an opportunity for the food industry due to its nutritional and functional properties. Currently, membrane processes with ultrafiltration (UF) take a very important position in the valorization of the whey and the study of these systems is main objective of this work. In the first stage of this work the aim was to characterize the whey and obtain whey protein concentrates (WPC) using a UF system with concentration factor of three. At the end of the process, the whey and the WPC were submitted to electrophoresis for the proteins’ fractionation study. Lastly, a technical/economical study was performed to understand the viability of implementation of the industrial scale membrane systems. The characterization of whey shows small differences between the several samples collected, which were all within the values described in the literature, except for the fat content that was higher. The concentration process allowed obtaining protein concentrates with 25 % protein, thus confirming the UF efficiency. The electrophoresis gel showed fractionation of the majority of proteins in the desired size, and the higher density of the β-lactoglobulin (β-lg) and α-lactalbumin (α-la) bands was clearly visible The technical/economical study analysed several alternatives for whey valorization with the membranes. In order to obtain liquid concentrates, the proposed system has a centrifuge and a membrane system (UF or nanofiltration – NF), while to obtain dry concentrates it was necessary the inclusion of a drying equipment. The NF system is the most advantageous because it allows increasing the profits, for the liquid concentrate and powder concentrate. The implementation of spray drying, despite its higher initial and operating costs, reveals to be advantageous because the product is sold directly in powder form, thus improving its value. The system may equally be used to produce butter with low content of salt.