Abstract The objective of this work was to investigate the application of microwave vacuum drying (MWVD) as a fast drying method to produce salted-and-dried beef cuts. Moreover, aiming to reduce the sodium content in the meat product, the partial replacement of NaCl by KCl during the salting stage was also investigated. To this end, beef cuts were salted by immersion in one of three saline solutions before drying: Solution A- 100% NaCl; Solution B- 75% NaCl and 25% KCl; and (iii) Solution C- 50% NaCl and 50% KCl. The proposed MWVD method was compared with convective drying (CD) and vacuum drying (VD) in terms of drying kinetics as well as physicochemical and mechanical properties of obtained samples. The average drying times for the samples to reach water activity of 0.7 was more than 40 h for CD, 36 h for VD, and 0.45 h for MWVD. The salting with different solutions had no influence in these times. Moreover, the MWVD samples presented higher values of porosity and rehydration capacity. Thus, the results presented in this study have technological importance for the design of new industrial technologies to produce salted-and-dried meat, as charque and jerked beef, with lower sodium content.

Abstract The objective of this study was to develop films with reduced hygroscopicity and improved mechanical properties from acetylated cassava starch. For that, an acetylation procedure using acetic anhydride as the esterification reagent was performed, resulting in starch acetates with degrees of substitution (DS) of 0.6 (S0.6) and 1.1 (S1.1). Twelve films formulations were studied: native cassava starch (S), starch acetate S0.6 and S1.1, with two glycerol concentrations (0.25 g.100 g-1 (25) and 0.30 g.100 g-1 (30)). The films were conditioned at the relative humidities (RH) of 58% and 75% for 96 h before characterization. Water vapor permeability, water solubility, water sorption isotherms, microstructural analyses, and mechanical properties in different relative humidity and different glycerol concentration were performed. Starch acetate films (S1.1) resulted in lower water vapor permeability (2.35 ± 0.26 × 10-7g/m.s.Pa) and water solubility (21.2 ± 0.16 g.100 g-1) than native starch films (3.79 ± 0.26 × 10-7 g/m.s.Pa and 25.46 ± 0.12 g.100 g-1). S0.6 films showed higher tensile strength (8.42 ± 0.84 MPa) than S1.1 films (6.93 ± 0.55 MPa). The results indicated that acetylated starch can be used to produce films with improved mechanical properties, with less water solubility and permeability to water vapor, especially when starch acetate with 0.6 DS and low glycerol concentration are used. Chemical compounds used in this article: Starch, acetate (PubChem CID: 24832118); Acetic acid (PubChem CID: 176); Acetic anhydride (PubChem CID: 7918); Sulfuric acid (PubChem CID: 1118); Glycerol (PubChem CID: 753).

Abstract Empirical sigmoidal models have been widely applied as primary models to describe microbial growth in foods. In predictive microbiology, the maximum specific growth rate (µ max ) and the lag phase (λ) are the parameters of some models and have been considered as biological parameters. The objective of the current study was to propose mathematical equations to obtain the parameters μ max and λ for any sigmoidal empirical growth model. In a case study, the performance was compared of two models based on empirical parameters and two models based on biological parameters. These models were fitted to experimental data for Lactobacillus plantarum in six isothermal conditions. Some advantages of the proposed approach were the practical and biological interpretation of these parameters, and the useful information of the secondary modeling describing the dependence of µ max and λ with the temperature.

Abstract The objective of this research was to evaluate the ability and efficiency of different software tools for the deconvolution of DSC thermograms of protein denaturation in salted beef. The salted samples were obtained by immersing beef pieces in NaCl solutions with concentrations of 20, 50, 100 and 330 g NaCl L-1 of water for 48 hours at 10 °C. The raw beef were used as control samples. Three software tools were considered: (i) Pyris7, (ii) OriginPro v.8, and (iii) Solver tool from MS-Excel. These computer programs were used for estimating the thermal denaturation temperature of myosin, sarcoplasmic proteins, and actin, as well as the value of denaturation enthalpy of these proteins. Based on the results obtained, we concluded that the model developed and programmed in MS-Excel showed better agreement with the data found in literature than the results obtained with the Pyris and OriginPro tools.

Abstract Chopped mussel meat packaged in retort pouches was processed in a laboratory-scale water immersion retort, adapted for processing under overpressure conditions. Retort temperature effects on product yield and on cook value were evaluated by setting the F0 at 7 min. The effects of different pre-treatments (salting and marination) on the characteristics of mussels were evaluated after processing at retort temperature of 118 °C and during a whole year of storage at 25 °C. The salted samples showed better yield during storage, while no differences were found for the other physicochemical parameters.

The aim of this study was to establish primary and secondary models to describe the growth kinetics of Byssochlamys fulva on solidified apple juice at different temperatures. B. fulva was inoculated on solidified apple juice at 10, 15, 20, 25 and 30 °C. Linear-with-breakpoint, Baranyi and Roberts, and Huang primary models (without upper asymptote) were fitted to the data, and they showed good ability to describe the growth kinetics. B. fulva showed longer adaptation time on apple juice than on culture medium, but growth rates were similar as reported in the literature. The dependence of µmax and λ parameters on temperature was described with Square Root and Arrhenius-Davey secondary models, respectively. These models were important to establish process/storage conditions and apple juice shelf life.

O objetivo deste trabalho foi avaliar processos de espalhamento e secagem de filme de amido-glicerol-fibras de celulose, preparado por "tape-casting". O espalhamento da suspensão foi avaliado a 50, 150 e 250 cm min-1, seguido de secagem em estufa com circulação forçada de ar, a 40 ou 70ºC; avaliou-se também o espalhamento da suspensão a 150 cm min-1, seguido da secagem do filme sobre suporte de "tape-casting" a 22ºC e 60% de umidade relativa, com velocidades do ar de 4, 6 e 8 m s-1 no túnel de secagem. Ensaios reológicos mostraram que o espalhamento das suspensões a temperaturas inferiores a 50ºC apresentou módulo de elasticidade superior ao módulo viscoso, em todo o espectro de frequências de oscilação. As microscopias mostraram filmes secos a 40 e 70ºC sem defeitos de formação, e cujas propriedades mecânicas não diferiam. A velocidade de espalhamento e a do ar não modificam o tempo de secagem nem as propriedades dos filmes. O tempo de secagem pode ser reduzido para aproximadamente duas horas, o que é importante para a produção dos filmes em larga escala.

The objective of this work was to evaluate spreading and drying processes of starch-glycerol-cellulose fiber film prepared by tape-casting. Suspension spreading was evaluated at 50, 150 and 250 cm min-1, followed by drying in a forced-air oven at 40 or at 70ºC; suspension spreading was also evaluated at 150 cm min-1, followed by film drying on the tape-casting support at 22ºC and 60% relative humidity, at air-drying velocity of 4, 6, and 8 m s-1 in the drying tunnel. Rheological tests showed that suspension spreading at temperatures below 50ºC had the modulus of elasticity superior to the modulus of viscosity, in all oscillation frequency spectrum. Micrographs showed films dried at 40 and 70ºC without defects and whose mechanical properties showed no differences. Spreading speed and air-drying velocities did not change the drying time and film properties. The drying time can be reduced to approximately two hours, which is important to the scale-up of film production.

Para a preparação de refeições rápidas é comum o uso de legumes cozidos. A integração dos processos de cozimento e resfriamento de cenouras em um mesmo tanque pelo uso do resfriamento a vácuo é descrito neste artigo. A combinação de diferentes métodos de cozimento e resfriamento a vácuo foi investigada. O processo integrado de cozimento-resfriamento a vácuo em um mesmo tanque permitiu obter cenouras cozidas-resfriadas com temperaturas finais de 10 ºC, o que é adequado à preparação de refeições rápidas com segurança. Quando o processo de cozimento-resfriamento foi realizado com amostras imersas em água de cozimento, a perda efetiva de massa foi de aproximadamente 3,6%. Quando o processo de cozimento-resfriamento foi realizado com amostras imersas em água fervente ou vapor, e o resfriamento a vácuo foi realizado após drenagem da água de cozimento, a perda de massa ficou entre 15 e 20%, ocasionando mudanças na textura dos produtos. Estes problemas podem ser compensados pela etapa de reidratação, utilizando pequena quantidade de água resfriada estéril. As propriedades de textura das amostras de cenoura reidratadas sob condição de vácuo e sob pressão atmosférica foram similares. Portanto, o processo integrado de cozimento-resfriamento a vácuo de cenouras em um mesmo tanque é uma alternativa viável para o processamento deste tipo de produto.

Cooked vegetables are commonly used in the preparation of ready-to-eat foods. The integration of cooking and cooling of carrots and vacuum cooling in a single vessel is described in this paper. The combination of different methods of cooking and vacuum cooling was investigated. Integrated processes of cooking and vacuum cooling in a same vessel enabled obtaining cooked and cooled carrots at the final temperature of 10 ºC, which is adequate for preparing ready-to-eat foods safely. When cooking and cooling steps were performed with the samples immersed in boiling water, the effective weight loss was approximately 3.6%. When the cooking step was performed with the samples in boiling water or steamed, and the vacuum cooling was applied after draining the boiling water, water loss ranged between 15 and 20%, which caused changes in the product texture. This problem can be solved with rehydration using a small amount of sterile cold water. The instrumental textural properties of carrots samples rehydrated at both vacuum and atmospheric conditions were very similar. Therefore, the integrated process of cooking and vacuum cooling of carrots in a single vessel is a feasible alternative for processing such kind of foods.

Processos de desidratação e de rehidratação de cogumelos da espécie Pleurotus ostreatus foram avaliados neste trabalho. Os cogumelos foram desidratados a 40, 50 e 60 ºC, com umidade relativa do ar de 75 %. O processo de rehidratação foi avaliado para diferentes temperaturas de água de imersão (25, 55 e 85 ºC) e diferentes tempos de imersão (30, 75 e 120 minutos). A melhor temperatura de secagem foi 40 ºC, levando em consideração a melhor rehidratação dos cogumelos desidratados nesta temperatura. A rehidratação pode ser feita em água a temperatura ambiente, por 30 minutos. Isotermas de sorção de umidade de amostras foram determinadas a 30, 40 e 50 ºC.Tanto o modelo de GAB quanto o de BET representaram satisfatoriamente os dados experimentais de isoterma de sorção de umidade.

Dehydration and rehydration processes of Pleurotus ostreatus fruiting bodies were investigated in this work. Mushroom samples were dehydrated at 40, 50 and 60 ºC, using drying air with relative humidity of 75 %. The rehydration was investigated at different temperatures of immersion water (25, 55 and 85 ºC) and different immersion times (30, 75 and 120 minutes). The best rehydration occurred for the samples dried at 40 ºC. The rehydration could be done in water at room temperature, during 30 minutes. Water sorption isotherms of samples were determined at 30, 40 and 50 ºC. Both GAB and BET models satisfactorily represented the experimental data of moisture sorption of dried mushrooms.

As carcaças de aves devem ser rapidamente resfriadas reduzindo a temperatura do centro do músculo peitoral de aproximadamente 40 a 4 °C, o que é crucial para garantir inocuidade do produto. Este trabalho avaliou o resfriamento de carcaças de frango através da imersão em água. As carcaças foram coletadas diretamente da linha de processamento industrial e resfriadas em um tanque piloto de resfriamento construído para avaliar a influência do método e da intensidade da agitação da água no resfriamento das carcaças. Um modelo matemático simplificado foi utilizado para representar os resultados experimentais. Estes resultados indicaram claramente que a compreensão e a quantificação da transferência de calor entre as carcaças e a água de resfriamento são essenciais para a melhoria dos processos e equipamentos. O modelo matemático proposto é uma ferramenta útil para representar a dinâmica de resfriamento das carcaças, podendo ser utilizada para comparar diferentes equipamentos e condições operacionais nas plantas industriais. Assim, este trabalho contribui com dados e com uma ferramenta matemática para tratar um recorrente problema industrial com poucas informações disponíveis na literatura.

Poultry carcasses have to be chilled to reduce the central breast temperatures from approximately 40 to 4 °C, which is crucial to ensure safe products. This work investigated the cooling of poultry carcasses by water immersion. Poultry carcasses were taken directly from an industrial processing plant and cooled in a pilot chiller, which was built to investigate the influence of the method and the water stirring intensity on the carcasses cooling. A simplified empiric mathematical model was used to represent the experimental results. These results indicated clearly that the understanding and quantification of heat transfer between the carcass and the cooling water is crucial to improve processes and equipment. The proposed mathematical model is a useful tool to represent the dynamics of carcasses cooling, and it can be used to compare different chiller operational conditions in industrial plants. Therefore, this study reports data and a simple mathematical tool to handle an industrial problem with little information available in the literature.

Amido de mandioca, calcário dolomítico e fibras celulósicas de eucalipto foram usados para preparar bandejas biodegradáveis que podem ser usadas como embalagens para alimentos. A influência da concentração de fibras na formulação dos compostos foi investigada, usando 5, 10, 15, 20, 30 e 40% de fibras. Os resultados indicaram que o aumento na concentração de fibras celulósicas promove uma diminuição na densidade e na resistência a tração das amostras. A tensão na ruptura para as bandejas contendo 5% de fibras celulósicas foi de 3,03 MPa, enquanto as bandejas comerciais de poliestireno expandido (EPS) usadas para embalagens alimentícias em supermercados apresentaram uma tensão de 1.49 MPa. A elongação na ruptura das bandejas obtidas neste trabalho variou ligeiramente com o aumento da concentração de fibra celulósica, os valores são aproximadamente 20% mais baixos do que a elongação na ruptura observada para bandejas comerciais de poliestireno expandido. Os resultados indicaram que as propriedades das bandejas devem ser melhoradas na utilização de embalagem de alimentos úmidos. Assim os materiais desenvolvidos neste trabalho representam uma possível alternativa para o uso de bandejas de EPS para embalar alimentos secos. As propriedades das bandejas necessitam ser melhoradas para sua utilização com alimentos úmidos.

Cassava starch, dolomitic limestone and eucalypt cellulose fibres were used to prepare foam trays that could be used to pack foodstuffs. The influence of the cellulose fibre concentration in the composite formulation was investigated using 5, 10, 15, 20, 30 and 40% of fibres. The results indicated that an increase in cellulose fibre concentration promoted a decrease in density and tensile strength of the foam samples. The tensile strength at break for foam trays containing 5% of cellulose fibres was 3.03MPa, whilst the commercial trays of expanded polystyrene used to pack foods in supermarkets presented a tensile strength of 1.49 MPa. The elongation at break of the foam trays obtained in this work varied slightly with increase in cellulose fibre concentration, the values being about 20% lower than the elongation at break observed for commercial foam trays of expanded polystyrene. Thus, the materials developed in this work represented a possible alternative to the use of EPS foam trays for packing dry foods. The trays' properties need to be improved for their use with moist foods.

O congelamento de cortes de frango em túneis convectivos é normalmente realizado com o produto envolto por filmes de polietileno de baixa densidade (PEBD, embalagem primária) e acondicionado em caixas de papelão (CP, embalagem secundária). O objetivo deste trabalho foi avaliar o efeito da embalagem secundária no congelamento dos cortes de frango. Para isso, compararam-se as curvas de congelamento do produto processado acondicionado em caixas metálicas perfuradas (CMP), que praticamente eliminam a resistência térmica da embalagem secundária, com as curvas de congelamento do produto nas CP. Os ensaios, realizados em uma planta industrial de processamento de aves, indicaram que as CP possuem uma grande resistência térmica e que a substituição delas por PMB pode resultar em maior homogeneidade espacial do processo de congelamento e em tempos de processo 45% inferiores. A duração do patamar de temperaturas que caracteriza a etapa de solidificação foi sensivelmente reduzida, o que favorece a obtenção de produtos congelados de melhor qualidade. A aparência dos produtos congelados em CMP não foi afetada, devido à proteção oferecida pelo PEBD. Assim, a substituição das caixas de papelão por caixas metálicas perfuradas pode ser uma excelente alternativa para reduzir o tempo de congelamento e melhorar sua homogeneidade espacial em túneis industriais.

Freezing of poultry cuts in continuous convective air blast tunnels is normally performed with the products protected by Low Density Polyethylene (LDPE) as a primary packaging and using Corrugated Cardboard Boxes (CCB) as secondary packaging. The objective of this work was to investigate the influence of these secondary packaging on the freezing of poultry cuts in continuous convective air blast tunnels. The study was performed by replacing CCB with Perforated Metal Boxes (PMB) in order to remove the packaging thermal resistance. The assays, performed in a industrial plant, demonstrated that CCB used commercially for meat freezing have a high heat transfer resistance. Their replacement with PMB can lead to shorter freezing times and spatially homogeneous freezing. Reductions of up to 45% in the freezing times were observed using PMB. The plateau of the temperature curve, related to the freezing time of free water, was significantly reduced using PMB, which is accepted to lead to better product quality after thawing. As the products were protected by the LDPE films as primary packaging, their appearance were not affected. The results presented in this work indicate that replacing CBB with PMB can be an excellent alternative to reduce freezing time and improve freezing homogeneity in industrial air blast tunnels, which could also be applied to other products.

O presente trabalho foca no impacto da concentração de O2, CO2 e etileno no controle da taxa de amadurecimento de bananas, como contribuição para o desenvolvimento de equipamentos domésticos que permitam o controle pelo próprio usuário da vida de prateleira de frutas. Isto representa o ajuste das atividades metabólicas para garantir o controle do amadurecimento. Variáveis como concentração de etileno e CO2 e temperatura foram ajustadas para acelerar ou reduzir o processo, enquanto que o grau de maturação foi monitorado através de parâmetros físico-químicos e sensoriais. Desta forma, o objetivo deste trabalho foi avaliar a influência destes parâmetros para controlar o amadurecimento de banana. A temperatura ótima de amadurecimento foi 25ºC. A presença de O2, a retirada de CO2 e a injeção de etileno foram relevantes no processo. A qualidade "pronto-para-consumo" foi obtida em 6 dias em sistema confinado. O uso de etileno como gatilho é adequado para acelerar o amadurecimento, com vantagens para a cor do produto.

The present work focuse on the impact of O2, CO2 and ethylene concentrations on ripening rate control of bananas as a contribution for the development of domestic equipments that could allow the user to drive the fruit shelf live. It represented the adjustment of metabolic activity rates in order to manage the maturity process. Ripening variables such as ethylene and CO2 concentrations and temperature were adjusted to accelerate or slow down the process, while the maturity degree was monitored through the physical and chemical parameters and sensorial analysis. Therefore, the objective of this work was to evaluate the influence of these parameters to manage the banana ripening. The optimum temperature was at 25 ºC of storage. The presence of oxygen, CO2 withdraws and ethylene injection were relevant for the ripening process. The "ready-to-eat" quality was achieved in 6 days in confined system. The use of ethylene as trigger was adequate to accelerate the ripening process with advantages in fruit color.

A impregnação a vácuo (VI) de alimentos é realizada pela aplicação de vácuo em um tanque contendo o produto imerso em uma solução, seguida da recuperação da pressão atmosférica. Neste trabalho, estudou-se o efeito da temperatura da solução de sacarose nas propriedades mecânicas das amostras e na perda de água (WL), ganho de sólidos (SG) e redução de peso (WR). A faixa de temperaturas estudada foi de 10 a 50 ºC, usando uma solução de sacarose com 50 ºBrix. As propriedades mecânicas das amostras foram estudadas através de ensaios mecânicos de deformação-relaxação. O SG variou entre 10.57 e 14.29 %, enquanto WL variou entre 10.55 e 14.48 %. O teor de sólidos das frutas tratadas aumentou com a temperatura, provavelmente devido à diminuição da viscosidade da solução. A tensão máxima foi maior a 10 ºC, diminuindo com a temperatura, devido ao amolecimento da estrutura.

The effect of sucrose solution temperature on the mechanical properties, water loss (WL), solids gain (SG) and weight reduction (WR) of apples (Fuji var.) treated by vacuum impregnation was studied. Temperatures were varied from 10 to 50 ºC, using a sucrose solution of 50 ºBrix. The mechanical properties were studied throughout a stress relaxation test. The results showed that the SG varied between 10.57 and 14.29 % and the WL varied between 10.55 and 14.48 %. The treated fruit soluble solids increased with the temperature probably due to the lower viscosity of the solution. The maximum stress was highest at 10 ºC, decreasing at higher temperatures, probably due the softening of the structure.

A impregnação a vácuo (IV) tem sido estudada como uma alternativa para reduzir o tempo dos processos de salga aplicados a diversos alimentos. Neste trabalho, foi investigada a influência da aplicação de vácuo no processo de salga de cortes de peito de frango. Os cortes foram submersos em soluções com diferentes concentrações de NaCl para a avaliação de dois processos distintos de impregnação de sal: a) processo inteiramente a pressão atmosférica (IPA); e b) com aplicação de vácuo seguido do restabelecimento da pressão atmosférica (IV). A transferência de massa entre a amostra e a solução salina foi avaliada através das determinações de ganho de água (GA), ganho de sal (GS) e ganho de massa total (GM) pelas amostras submetidas à IV e à IPA. A comparação entre os processos de IV e IPA, com 6 horas de imersão, indicou que a utilização de um período inicial de vácuo pode incrementar o GA, GS e GM em 78, 25 e 54%, respectivamente. Isso se deve à contribuição sinérgica do mecanismo hidrodinâmico (HDM) aos mecanismos osmóticos e difusivos existentes. Deste modo, a IV pode ser considerada como uma alternativa de processo para a salga de cortes de carne de frango. No entanto, deve-se estar atento para que os ganhos de água e sal sejam compatíveis com as exigências legais e tecnológicas.

Vacuum impregnation has been studied as an alternative for reducing time in the salting process applied to different kinds of food. In this study, the influence of vacuum application on the salting process of chicken breast cuts was evaluated. The chicken samples were submerged in solutions with different NaCl concentrations and two processes were evaluated: a) a process entirely under atmospheric pressure (API); and b) a process with vacuum application followed by atmospheric pressure restoration (VI). Mass transfers were characterized by water gain (WG), salt gain (SG), and total weight increment (WI). The comparison between the VI and API processes, with 6 hours of immersion time, indicated that the utilization of an initial vacuum period can increase the WG, SG and WI in 78, 25 and 54%, respectively. This is due to the synergistic contribution of the hydrodynamic mechanisms (HDM) to the existing osmotic and diffusive mechanisms. Thus, VI can be considered as an alternative for the salting process of chicken cuts. However, special care must be taken in order to assure that water and salt increments are compatible with legal and technological requirements.