<p>  </p> <p>  In this study, whey protein isolate (WPI) and high gellan gum (HAGG) were selected as natural ingredients to produce food-grade biopolymer particles for stabilizing the air-water interface. To achieve this, different mixing ratios of WPI and HAGG were employed, and heat treatment was implemented at different pH levels under the same concentration based on investigations of the pH-driven phase behavior of the WPI/HAGG complex system. The resulting WPI/HAGG complex particles were then evaluated for their ability to stabilize air-water interfaces by measuring their foaming properties.</p> <p><br></p> <p>  Foams generated using 0.1% (wt/wt) WPI/HAGG complex particles, heated at pH 5 with the mixing ratio 2:1 has demonstrated enhanced stability over a period of 30 hours compared to the WPI alone. The unique properties of these complex particles, including their smaller size (around 500nm), greater negative charge (more negative than -30 mV), and compact spherical core-shell structure, along with the higher viscosity in the continuous phase as well as the presence of small protein particles and gellan chains at the interface, collectively contribute to their superior performance as foam stabilizers. This allows for the creation of aerated food products with desirable characteristics, including product handling, enhanced texture, and prolonged shelf life in food industry.</p>

<p>Temperature is the common accelerant that is used for shelf-life determination of shelf-stable food because it is easy to use and there are models such as Q₁₀and Arrhenius, which are available for shelf-life prediction. The accelerated shelf-life test (ASLT) still requires months of analysis time as it only uses temperature as the accelerant. Oxygen pressure as an accelerant has not been given much attention even though many studies have shown the negative impact of oxygen on the shelf-life of food. An effective analysis method with multiple accelerants has the potential for the development of a rapid shelf-life determination method. Hence, this research focused on the invention of a rapid method, named the Ultra-Accelerated Shelf-Life Test (UASLT) that combines oxygen pressure and temperature as accelerants and the development of shelf-life prediction model(s). The study hypothesized that the application of elevated oxygen pressure and elevated temperature (40C) increases the amount of oxygen diffusing into packaged food which leads to rapid degradation of nutrients that further reduces the overall shelf-life analysis time compared to the ASLT method. A custom-made high-pressure chamber with a 100% oxygen environment at 40C was designed and developed as part of the UASLT method. The impact of the application of oxygen pressure on oxygen diffusivity in polymeric food packaging materials was investigated on three packages with different oxygen permeability properties. The application of oxygen pressure significantly increased the rate of oxygen transfer and the oxygen diffusivity values for all packaging materials compared to the counterparts that were not exposed to the pressure. A shelf-stable model food fortified with vitamins A, B1, C and D3 was developed to investigate the effectiveness of the UASLT method in degrading the quality indicators in the model foods in a polyethylene terephthalate (PET) container. PET was chosen as it was the most permeable to oxygen. Model food was also subjected to ASLT conditions at the same temperature without additional pressure and at room temperature (control). A degradation of 27.1 ± 1.9%, 13.9± 2.1%, 35.8 ± 1.0%, and 35.4 ± 0.7% were seen in vitamins A, B1, C and D3, respectively, in just 50 days. Slower degradation was observed with samples kept under the ASLT conditions for 105 days and reached a degradation of 24.0 ± 2.0%, 4.9 ± 6.1%, 32.0 ± 3.1% and 25.1 ± 1.5% for vitamin A, B1, C and D3, respectively. The control samples that were studied for 210 days showed 14.9 ± 5.0%, 2.0 ± 2.2%, 13.8 ± 2.2% and 10.6% ± 0.8% degradation in vitamins A, B1, C and D3, respectively. The increase in the dE values due to browning in samples kept at the UASLT, ASLT and control conditions were 11.67 ± 0.09, 7.49 ± 0.19 and 2.51 ± 0.11, respectively. The degradation of vitamins A, C, D3 was analyzed using the 1st order kinetic and the rate constant,    (day^-1) was used to develop four prediction models. Vitamin B1 values were omitted from the kinetic analysis due to insufficient degradation. Two temperature-oxygen diffusion models were developed by correlating oxygen diffusivity and   . Comparisons were made with the temperature-based models of    and Arrhenius. The predicted    values across the models were in the range of 0.051-0.054 day^-1,0.080-0.088 day^-1 and 0.048-0.051 day^-1, for vitamin A, C and D3, respectively. The    values estimated for vitamins A, C, and D3 were 2.16, 2.63 and 2.62, respectively. The predicted shelf-life of vitamin A, C and D3 to undergo 25% reduction was in the range of 404 to 551, 321-353 and 529-583 days across all models, respectively. The shelf-life predicted from the temperature-oxygen diffusion models was close to the temperature models indicating the potential to be paired with the UASLT method. Experimental verification is needed to analyze the errors in the prediction. The addition of oxygen pressure further reduced the shelf-life analysis time by 50% compared to ASLT. Elevated external oxygen pressure can be used as an accelerant along with elevated temperatures (40C) for rapid shelf-life testing of packaged foods. This novel approach has potential application in the food industry for faster shelf-life analysis of food.</p>

<p dir="ltr">The impacts of processing on protein structure are of broad interest to the food science community including ingredient producers, product developers, and researchers. Processing and isolation steps induce protein structural changes which occur due to temperature based, shear, and chemical inputs, leading to denatured protein with different functionalities. However, exploration of the protein folding landscape as a way to intentionally modify protein conformation is not widely understood in food science. This particularly applies to cold denaturation, which is the structural changes in protein as the result of low temperature treatments.</p><p dir="ltr">This work has two primary goals. The first was to develop understanding of protein conformations resulting from cold denaturation and its implications for food textural properties. Pea protein was selected for this work since it is a source of plant-based protein that has recently grown in popularity and contains many hydrophobic amino acids that would make is susceptible to cold denaturation. Cold denaturation was studied using physicochemical techniques including differential scanning calorimetry, Fourier transform infrared spectroscopy, zeta potential, fluorescence spectroscopy, dynamic light scattering, and rheology. These techniques are used to characterize untreated pea protein, and proteins that have been modified using different combinations of ethanol, shear forces, acidic conditions, extrusion, and temperatures below 0°C. Significant physicochemical differences are found as the result of low temperatures, driven by an increase in surface hydrophobicity and electrostatic interactions. These differences led to protein gelation through hydrophobic forces, changing the nature of gels. Similarly, the increase in protein hydrophobicity leads to more stable emulsions from these products and unique fatty extrudates.</p><p dir="ltr">A second aim of this work developed bioinformatic models to interpret physiochemical data and provide mechanistic understanding of the process, as well as predict functional properties based on protein models. Strong correlations are found for the zeta potential, secondary structure, hydrogen bonds, and surface hydrophobicity. These models are used to convert data into physicochemical energy and used to provide reasonable estimates of mechanical properties of pea protein in extrusion, gelation, and emulsification. Together, this work shows that cold denaturation may be a useful tool for food product developers creating fatty and creamy textures. It also suggests bioinformatic modeling as a tool to estimate protein functionality, which could lead to tremendous time savings in process and product design.</p>

<p dir="ltr">Liquid hydrogen peroxide (LHP) and vapor hydrogen peroxide (VHP) efficacy as a sterilant for <i>Bacillus atrophaeus</i> and <i>Geobacillus stearothermophilus</i> spores in aseptic packaging systems under commercial sterilization conditions were evaluated in this research. The work centers on quantifying and modeling the kinetic parameters that impact peroxide sterilization efficacy, including the D and z values, that relate to the change in concentration required for a 1-log reduction in spore population and a novel Z_conc parameter This comprehensive study is divided into four key investigations, each contributing critical insights to the overall understanding of peroxide sterilization processes.</p><p dir="ltr">The first study examined the inactivation kinetics of <i>B. atrophaeus</i> spores in liquid hydrogen peroxide. By evaluating different concentrations (20%, 28%, and 33%) and temperatures (up to 82.2°C), the study revealed that higher concentrations and elevated temperatures significantly enhanced spore inactivation. The Weibull model provided a more accurate fit for the data, indicating a non-linear relationship between spore reduction and exposure time.</p><p dir="ltr">The second part of the research explored the use of VHP for sterilizing <i>B. atrophaeus</i> spores. With VHP concentrations of 2500 ppm and 4450 ppm at various temperatures, the study demonstrated that higher concentrations and temperatures are highly effective for spore inactivation. Both log-linear and Weibull models accurately described the inactivation kinetics, with the Weibull model showing a slightly better fit, emphasizing the potential of VHP in achieving commercial sterility.</p><p dir="ltr">The third investigation focused on developing predictive models for VHP concentration and its efficacy in spore inactivation. The study evaluated VHP concentrations ranging from 2.32 mg/L to 7.35 mg/L and their impact on spore inactivation rates. The Weibull model proved particularly effective in predicting the inactivation of <i>G. stearothermophilus</i> and <i>B. atrophaeus</i> spores, offering a robust tool for optimizing sterilization protocols in aseptic packaging.</p><p dir="ltr">The fourth and final study of the research investigated the influence of surface roughness on spore survival during VHP sterilization cycles on plastic packaging materials. Artificial roughness on high-density polyethylene (HDPE) coupons was created using sandpaper with different grits. <i>B. atrophaeus</i> spores were applied to both roughened and smooth HDPE surfaces. The study finds that rougher surfaces provide more shelter for spores, reducing sterilization efficacy. For example, surfaces roughened with P-36 grit showed a 2.75 log reduction in spore count, whereas smoother surfaces with P-220 grit achieved a 4.42 log reduction. Contact angle measurements indicated that increased roughness led to more hydrophilic surfaces, with water contact angles decreasing from 149.7° for the pristine sample to 105.4° for the P-36 sample. Scanning electron microscopy (SEM) images confirmed that spores were more likely to reside in the valleys of rough surfaces, highlighting the importance of surface characteristics in optimizing VHP sterilization protocols.</p><p dir="ltr">The findings of this dissertation underscore the significant impact of hydrogen peroxide concentration, application conditions, and packaging material surface properties on the efficacy of spore inactivation during sterilization. By providing a comprehensive understanding of these factors, the research contributes to the development of optimized aseptic sterilization protocols, enhancing the reliability and safety of aseptically packaged food and pharmaceutical products. This work will ensure compliance with regulatory standards and improve food safety in commercial manufacturing, laying a solid foundation for future research and practical applications in VHP sterilization technology.</p>

Achocolatados e bebidas achocolatadas são alimentos muito consumidos em praticamente todos os países, especialmente por crianças e jovens. Isso porque o chocolate é também reconhecido como um agente flavorizante largamente aceito. O objetivo geral deste trabalho foi elaborar um estudo de achocolatados e de bebidas achocolatadas disponíveis no mercado brasileiro, desenvolvendo-se técnicas de análises e obtendo-se resultados com finalidades comparativas. Ainda formulou-se bebida achocolatada com características funcionais, utilizando-se para tal quitosana modificada desenvolvida no Departamento de Tecnologia Bioquímico-Farmacêutica. Este trabalho foi dividido em duas partes, para melhor leitura e compreensão: parte 1: Achocolatados e parte 2: Bebidas achocolatadas. Para os achocolatados foram realizadas análises em produtos disponíveis no mercado brasileiro, como: composição centesimal, teobromina, alcalóides totais e pH. Procurou-se enfatizar as diferenças entre os produtos para finalidades especiais (\"diet\" e \"light\") e os tradicionais. Ainda, estudou-se propriedades tisicas, como força de compactação, densidade e granulometria, observando a correlação entre estas. Para bebidas achocolatadas, desenvolveu-se produto com quitosana modificada, atribuindo ao produto características funcionais. Estudou-se a reologia deste produto e de outros obtidos no mercado brasileiro, avaliando-se assim o produto desenvolvido. O teor de sólidos solúveis avaliado nestas amostras, com resultados muito próximos, sugeriu certa padronização na adição de leite, açúcar e sólidos de cacau em suas formulações. Para a bebida desenvolvida, aplicou-se teste sensorial ( aceitação global e viscosidade), utilizando-se como comparativo bebida do mercado brasileiro (Chocomilk), escolhida por ser comercializada em embalagem de vidro (semelhante à do produto em estudo). A aceitação global não demonstrou diferença significativa (P>0,05) entre as amostras, porém a característica mais encorpada da bebida desenvolvida apontou maior tendência de aceitação neste parâmetro. / Chocolate drink powders and chocolate beverages are very consumed foods in almost every contry, specially by children and young people. That is because chocolate is also recognized as a flavour agent greatly accepted. The aim of this work was to elaborate a study of chocolate drink: powders and chocolate beverages from Brazilian market, developing analytical techniques and obtaining results with comparatives purposes. It was developed chocolate beverage with functional characteristics, using for that modified chitosan, developed in this Department. This work was divided into two parts to a better reading and understanding: part 1: Chocolate drink: powders and part 2: Chocolate beverages. In the first part, some chemical analysis were carried out in the products from Brazilian market, such as lipids, proteins ashes, moisture, theobromine and total alkaloids content and the pH. It was emphasized the differences between diet, light and the standard products; The theobromine and total alkaloids content was used as an indicative of the differences. Some physical analysis in the chocolate drink powders were carried out, such as compaction of powder, particle size distribution and poured density of powder. In the second part, it was carried out rheological analysis of the products from the market. It was developed chocolate beverage with modified chitosan as a thickening agent, what gave it a functional characteristic. The rheological characteristics of the developed product were similar to that of the products from the market. Soluble solids analysis was carried out, also making a comparison between the developed product and the products from the market. The results were very similar, showing a standardization of the quantity of sugar, milk and cocoa solids in their formulation. Besides that, it was carried out sensory analysis, with an acceptance test of the developed product and the beverage chosen for comparison - Chocomilk. With the marks of acceptance test (global acceptance and viscosity) it was made a comparison between the two samples. It was noticed that the developed sample was more accepted than the other one, talking about the viscosity, and in talking about the global acceptance, there wasn\'t significant difference (P>0,05) between the samples.

A elaboração e caracterização de sistemas tão complexos quanto alimentos não são temas que se esgotem ao longo de um único trabalho. Assim, tomando como ponto de partida o desenvolvimento de formulações para sorvetes, são apresentados os princípios gerais da criação e estabilização de um dos gêneros alimentícios mais apreciados n.o mundo todo. O primeiro capítulo aborda interações que ocorrem entre componentes de uso comum na maioria dos alimentos processados e, de modo específico, o papel desempenhado por cada um deles em formulações para sorvetes. São apresentadas características das matérias-primas especiais empregadas no desenvolvimento das formulações propostas, bem como fundamentos de reologia. Tratam-se os princípios gerais do fenômeno speckle, ferramenta bastante útil em caracterizações estruturais, porém ainda pouco explorada na área alimentícia. O segundo capítulo apresenta as formulações para sorvetes que foram elaboradas para este trabalho e os resultados de caracterizações físico-químicas tomadas sobre alguns dos ingredientes utilizados, bem como sobre os produtos finais desenvolvidos. O terceiro capítulo exibe os resultados das avaliações reológicas feitas em ingredientes e misturas formuladas para este estudo. A partir do perfil demonstrado pelos reogramas, interações microscópicas puderam ser cogitadas. Mostram-se também, imagens tomadas por um sistema de videomicroscopia acoplado ao reômetro (módulo Rheoscope), onde puderam ser observadas deformações estruturais em tempo real ocorridas com as amostras durante as avaliações. O quarto capítulo propõe uma nova metodologia de investigação estrutural na qual a análíse dos resultados gerados a partir de um fenômeno de interferência possibilita mapear a evolução da microestrutura de sorvetes ao longo do tempo, quando submetidos a diferentes condições de temperatura. / Elaboration and characterization of systems with high leveI of complexity as foods cannot discussed in an only study. In this work, from development of special ice cream formulations are presenteei the general principIes of creation and stabílízation of one of the most appreciated foodstuffs. In first chapter the interactions that occur among components of current/y use in processed foods and, in a specific manner, the role of each one in ice cream formulations. Characteristics of the special raw materiais employed in development of the proposed formulatíons are presenteei, as well fundamental concepts of rheological behavior. Also, general principies of speckle phenomenon are presented, a very useful tool to structural investigations in several systems, but few explored in food science and technology. In second chapter are presented the ice cream formulations that were elaborated by this research and the results of analysis of both composition and chemical properties taken on some ingredients as well in developed products. In third chapter are exhibited the results from rheological assessments performed in ingredients and formulated ice cream mixes. From rheological curves, microscopic interactions could be cogitated. Images taken by a system of microscopy connected to rheometer shown structural deformatíons in real time occurred with the samples during the evaluations. In fourth chapter is showed a new methodology of structural investigation in which the analysis of results obtained from interference phenomenon allow to generate a map of temporal evolution of ice creams along the time, at different temperature conditions.

Achocolatados e bebidas achocolatadas são alimentos muito consumidos em praticamente todos os países, especialmente por crianças e jovens. Isso porque o chocolate é também reconhecido como um agente flavorizante largamente aceito. O objetivo geral deste trabalho foi elaborar um estudo de achocolatados e de bebidas achocolatadas disponíveis no mercado brasileiro, desenvolvendo-se técnicas de análises e obtendo-se resultados com finalidades comparativas. Ainda formulou-se bebida achocolatada com características funcionais, utilizando-se para tal quitosana modificada desenvolvida no Departamento de Tecnologia Bioquímico-Farmacêutica. Este trabalho foi dividido em duas partes, para melhor leitura e compreensão: parte 1: Achocolatados e parte 2: Bebidas achocolatadas. Para os achocolatados foram realizadas análises em produtos disponíveis no mercado brasileiro, como: composição centesimal, teobromina, alcalóides totais e pH. Procurou-se enfatizar as diferenças entre os produtos para finalidades especiais (\"diet\" e \"light\") e os tradicionais. Ainda, estudou-se propriedades tisicas, como força de compactação, densidade e granulometria, observando a correlação entre estas. Para bebidas achocolatadas, desenvolveu-se produto com quitosana modificada, atribuindo ao produto características funcionais. Estudou-se a reologia deste produto e de outros obtidos no mercado brasileiro, avaliando-se assim o produto desenvolvido. O teor de sólidos solúveis avaliado nestas amostras, com resultados muito próximos, sugeriu certa padronização na adição de leite, açúcar e sólidos de cacau em suas formulações. Para a bebida desenvolvida, aplicou-se teste sensorial ( aceitação global e viscosidade), utilizando-se como comparativo bebida do mercado brasileiro (Chocomilk), escolhida por ser comercializada em embalagem de vidro (semelhante à do produto em estudo). A aceitação global não demonstrou diferença significativa (P>0,05) entre as amostras, porém a característica mais encorpada da bebida desenvolvida apontou maior tendência de aceitação neste parâmetro. / Chocolate drink powders and chocolate beverages are very consumed foods in almost every contry, specially by children and young people. That is because chocolate is also recognized as a flavour agent greatly accepted. The aim of this work was to elaborate a study of chocolate drink: powders and chocolate beverages from Brazilian market, developing analytical techniques and obtaining results with comparatives purposes. It was developed chocolate beverage with functional characteristics, using for that modified chitosan, developed in this Department. This work was divided into two parts to a better reading and understanding: part 1: Chocolate drink: powders and part 2: Chocolate beverages. In the first part, some chemical analysis were carried out in the products from Brazilian market, such as lipids, proteins ashes, moisture, theobromine and total alkaloids content and the pH. It was emphasized the differences between diet, light and the standard products; The theobromine and total alkaloids content was used as an indicative of the differences. Some physical analysis in the chocolate drink powders were carried out, such as compaction of powder, particle size distribution and poured density of powder. In the second part, it was carried out rheological analysis of the products from the market. It was developed chocolate beverage with modified chitosan as a thickening agent, what gave it a functional characteristic. The rheological characteristics of the developed product were similar to that of the products from the market. Soluble solids analysis was carried out, also making a comparison between the developed product and the products from the market. The results were very similar, showing a standardization of the quantity of sugar, milk and cocoa solids in their formulation. Besides that, it was carried out sensory analysis, with an acceptance test of the developed product and the beverage chosen for comparison - Chocomilk. With the marks of acceptance test (global acceptance and viscosity) it was made a comparison between the two samples. It was noticed that the developed sample was more accepted than the other one, talking about the viscosity, and in talking about the global acceptance, there wasn\'t significant difference (P>0,05) between the samples.

A elaboração e caracterização de sistemas tão complexos quanto alimentos não são temas que se esgotem ao longo de um único trabalho. Assim, tomando como ponto de partida o desenvolvimento de formulações para sorvetes, são apresentados os princípios gerais da criação e estabilização de um dos gêneros alimentícios mais apreciados n.o mundo todo. O primeiro capítulo aborda interações que ocorrem entre componentes de uso comum na maioria dos alimentos processados e, de modo específico, o papel desempenhado por cada um deles em formulações para sorvetes. São apresentadas características das matérias-primas especiais empregadas no desenvolvimento das formulações propostas, bem como fundamentos de reologia. Tratam-se os princípios gerais do fenômeno speckle, ferramenta bastante útil em caracterizações estruturais, porém ainda pouco explorada na área alimentícia. O segundo capítulo apresenta as formulações para sorvetes que foram elaboradas para este trabalho e os resultados de caracterizações físico-químicas tomadas sobre alguns dos ingredientes utilizados, bem como sobre os produtos finais desenvolvidos. O terceiro capítulo exibe os resultados das avaliações reológicas feitas em ingredientes e misturas formuladas para este estudo. A partir do perfil demonstrado pelos reogramas, interações microscópicas puderam ser cogitadas. Mostram-se também, imagens tomadas por um sistema de videomicroscopia acoplado ao reômetro (módulo Rheoscope), onde puderam ser observadas deformações estruturais em tempo real ocorridas com as amostras durante as avaliações. O quarto capítulo propõe uma nova metodologia de investigação estrutural na qual a análíse dos resultados gerados a partir de um fenômeno de interferência possibilita mapear a evolução da microestrutura de sorvetes ao longo do tempo, quando submetidos a diferentes condições de temperatura. / Elaboration and characterization of systems with high leveI of complexity as foods cannot discussed in an only study. In this work, from development of special ice cream formulations are presenteei the general principIes of creation and stabílízation of one of the most appreciated foodstuffs. In first chapter the interactions that occur among components of current/y use in processed foods and, in a specific manner, the role of each one in ice cream formulations. Characteristics of the special raw materiais employed in development of the proposed formulatíons are presenteei, as well fundamental concepts of rheological behavior. Also, general principies of speckle phenomenon are presented, a very useful tool to structural investigations in several systems, but few explored in food science and technology. In second chapter are presented the ice cream formulations that were elaborated by this research and the results of analysis of both composition and chemical properties taken on some ingredients as well in developed products. In third chapter are exhibited the results from rheological assessments performed in ingredients and formulated ice cream mixes. From rheological curves, microscopic interactions could be cogitated. Images taken by a system of microscopy connected to rheometer shown structural deformatíons in real time occurred with the samples during the evaluations. In fourth chapter is showed a new methodology of structural investigation in which the analysis of results obtained from interference phenomenon allow to generate a map of temporal evolution of ice creams along the time, at different temperature conditions.

A tecnologia de fabricação de bebidas lácteas envolve a mistura de leite e soro, podendo ser fermentada por bactérias do iogurte ou probióticas e adicionada de polpa de fruta e outros aditivos permitidos. O produto final deve conter bactérias lácticas viáveis em número adequado. Os objetivos deste trabalho foram desenvolver bebidas lácteas probióticas a partir das misturas leite-soro e estudar sua vida-de-prateleira. O efeito da composição da cultura probiótica (Lactobacillus delbrueckii subsp. bulgaricus, L. acidophilus, L. rhamnosus e Bifidobacterium animalis subsp. lactis em co-cultura com Streptococcus salivarius subsp. thermophilus) e o efeito do pH final da fermentação na cinética de acidificação, pós-acidificação e contagem de bactérias probióticas foram estudados em soro de queijo Minas frescal e em diferentes misturas leite-soro. Bebidas lácteas probióticas foram desenvolvidas a partir das diferentes misturas leite-soro e a vida-de-prateleira foi determinada ao longo de 28 dias de armazenamento do produto a 4°C. As características dos produtos foram seguidas pelas determinações físico-químicas, microbiológicas e sensoriais. O soro apresentou efeito positivo sobre a velocidade máxima das co-culturas estudadas, bem como as diferentes composições das co-culturas influenciaram o parâmetro estudado. Todas as culturas apresentaram contagens maiores em pH final de fermentação 4,5, quando comparadas às obtidas em pH 5,5. A co-cultura StLb foi a mais rápida a fermentar os diferentes meios estudados e, a StLr, a mais lenta. Com a adição de açúcar e de estabilizante, os parâmetros cinéticos mostraram comportamento diferenciado daqueles obtidos em misturas leite-soro. Nas bebidas lácteas, as contagens de B. lactis mantiveram-se acima do limite exigido pela legislação até 28 dias de armazenamento do produto refrigerado. A pós-acidificação, cor e reologia variaram durante o período de armazenamento, influenciando a análise sensorial, cujos atributos obtiveram maior aceitação em bebidas elaboradas com 10% de sólidos lácteos. Os resultados indicaram que a bebida láctea elaborada com a co-cultura StBl foi a melhor alternativa para desenvolvimento de uma bebida funcional com boas características sensoriais. / The technology of production of lactic beverages involves the mixture of milk fermented by yoghurt or probiotic bacteria and whey in appropriate proportions, and the addition of fruit pulp and other allowed additives. The final product should contain viable lactic bacteria in appropriate counts. The objective of this work was to develop a probiotic lactic beverage from milk-whey mixtures and to study its shelf-life. The effect of the composition of the probiotic culture (Lactobacillus delbrueckii ssp. bulgaricus, L. acidophilus, L. rhamnosus and Bifidobacterium animalis ssp. lactis in co-culture with Streptococcus salivarius subsp. thermophilus) and the effect of the pH of the end of fermentation in the acidification kinetics, post-acidification and counts of probiotic bacteria were studied in Minas frescal cheese whey and in different mixtures milk-whey. Probiotic lactic beverages were developed from different milk-whey mixtures and the shelf-life was determined along 28 days of storage of the product at 4°C. The characteristics of the products were followed by determination of post-acidification, total acidity, color, rheology, probiotic viability and sensorial analysis. Whey presented positive effect on maximum acidification rates of the studied co-cultures, as well as the different compositions of the co-cultures influenced the studied parameter. All cultures presented higher counts when fermentation was stopped at pH 4.5, when compared to pH 5.5. The co-culture StLb presented the fast acidification performance while StLr, the slowest. The addition of sucrose and stabilizer affected the acidification kinetic parameters. In probiotic lactic beverages, counts of B. lactis were higher than the limit required by the legislation until 28 days of cool storage of the product. The post-acidification, color and rheological parameters varied during shelf-life, influencing the sensorial analysis, whose attributes obtained higher acceptance in the elaborated beverage with 10% of total solids. The results indicated that the lactic beverage elaborated with the co-culture StBl was the best alternative for development of a functional lactic beverage with good sensorial characteristics.

Esta dissertação teve como propósito a implementação do Sistema de Qualidade no laboratório de análise sensorial da indústria de alimentos, baseando-se nos princípios das Boas Práticas de Laboratório (BPL) e Boas Práticas de Fabricação (BPF), visando contemplar os aspectos analíticos e processuais. Para isso, fez-se a abordagem das normas fundamentais e dos princípios estabelecidos pelas Boas Práticas, relacionadas com a estrutura organizacional, o gerenciamento das atividades e os critérios necessários para o funcionamento do laboratório de análise sensorial, assegurando a sistemática de padronização e otimização das operações. O laboratório de análise sensorial apresenta características exclusivas que são contempladas nas atividades de manipulação dos alimentos, durante preparação das amostras e atividades analíticas realizadas pelos provadores. Em função da especificidade das atividades desenvolvidas, foi necessária a elaboração de procedimentos específicos, levando-se em consideração todos os aspectos inerentes às operações, instalações, equipamentos, análises, produtos e pessoas. Após o processo de implementação do Sistema de Qualidade, foram realizados o monitoramento e a verificação pelo critério de auditorias periódicas, previamente programadas. Os resultados do processo de implementação demonstraram a aplicabilidade do Sistema de Qualidade, na extensão das atividades do laboratório de análise sensorial, em consonância aos princípios das BPL e BPF. O processo de monitoramento e verificação possibilitou, através das atividades de auditorias, promover a estabilização e melhoria do sistema implementado. / This dissertation had like purpose the Quality System implementation in the food industry sensory analysis laboratory, using the principles of Good Laboratory Practices (GLP) and Good Manufacturing Practices (GMP), aiming to contemplate the analytical and processual aspects. For this purpose, was made an examination of basic rules and principles established by the Good Practices related to the organizational structure, the managing activities and the necessary criteria to the sensory analysis laboratory operation, assuring the systematic of the operations standardization and optimization. The sensory analysis laboratory presents exclusive characteristics that are contemplated in the food handling activities, during the samples preparation and the analytical activities carried out by the panelists. Due to the specificity of the activities developed, it was necessary the elaboration of specific procedures, taking into account all of the inherent aspects to the operations, facilities, equipments, analysis, products and persons. After the Quality System implementation process, it was carried out the monitoring and verification by the periodic audits criterion, previously programmed. The results of the implementation process showed the Quality System applicability in the range of the sensory analysis laboratory activities, in consonance to the GLP and GMP principles. The monitoring and verification process was possible, by the audits activities, to promote the stabilization and the improvement of the implemented system.