RESUMO Conservantes naturais, como exemplo as enterocinas, têm sido foco de diversos estudos para uso na indústria de alimentos. No entanto, os meios comerciais utilizados para obtenção de enterocinas ainda são onerosos, sendo a grande desvantagem para produção em larga escala. Neste estudo foram desenvolvidas quatro formulações de meios de cultura contendo farinha de soja para obtenção de enterocina por Enterococcus durans MF5. A atividade antilisterial da enterocina MF5 obtida em meio soja e MRS (controle) foi testada contra Listeria monocytogenes CLIP2032 e L. innocua CLIP12612. O crescimento de E. durans (UFC/mL) foi significativamente afetado pelo tempo de incubação nos meios soja e MRS (p<0,05), porém a composição do meio não afetou o desenvolvimento celular do microrganismo produtor de enterocina. Ao avaliar os genes que codificam a síntese de enterocina, foram obtidos resultados positivos para enterocina A, B, P e X. Quando tratada com enzimas proteolíticas (α-quimotripsina, protease e proteinase-K), a enterocina foi inativada, confirmando seu caráter proteico. A atividade antilisterial das enterocinas obtidas em meio de soja foi de até 6.400 AU mL-1. Enterocina produzida nos meios de soja M1 e M2 apresentaram atividade antibacteriana na concentração de 1 mg/mL após 6 h de incubação. Assim, mostramos que meios de cultura formulados com farinha de soja são substratos promissores para a produção de enterocinas que permitiriam a expansão do protocolo em larga escala.

ABSTRACT Natural preservatives, such as enterocins, have been the focus of several studies for use in the food industry. However, the commercial media used to obtain enterocins are still expensive, presenting a disadvantage for large-scale production. In this study was developed four formulations of culture media containing soybean flour for obtaining Enterococcus durans enterocins. The antilisterial activity of E. durans MF5 enterocins obtained in soybean and MRS media (control) was characterized, with Listeria monocytogenes CLIP2032 and L. innocua CLIP12612 as the bacterial strains. The growth of E. durans (CFU/mL) was significantly affected by the incubation time in the soybean and MRS media (p <0.05), but the composition of the media did not affect the cell development of the enterocin-producing microorganism. When evaluating the genes encoding enterocin synthesis, positive results were obtained for enterocin A, B, P, and X. When treated with proteolytic enzymes (α-chymotrypsin, protease, and proteinase-K), enterocin was inactivated, confirming its protein character. The antilisterial activity of the enterocins obtained in soybean media was up to 6,400 AU mL-1. Enterocins from soybean media M1 and M2 showed antibacterial activity at a concentration of 1 mg/mL after 6 h incubation. Thus, we show that culture media formulated with soybean flour are promising substrates for enterocin production that would allow the protocol to be expanded on a large scale.

Abstract The consumption of yerba mate beverages is related to several health benefits. These desirable properties are mainly due to the bioactive compounds. However, the levels of those compounds are directly affected by factors such as geographical origin. This study aimed to use chemometrics to evaluate the antioxidant compounds of yerba mate (consumed as chimarrão) marketed in southern Brazil. Neochlorogenic acid and caffeine were the main bioactive compounds found in this type of yerba mate beverage (chimarrão). The dataset was analyzed by chemometrics, and principal component analysis using the first three principal components explained 61.30% of the total variance. Hierarchical cluster analysis suggested three clusters, with cluster 1 containing the majority of the samples from the states of Rio Grande do Sul and Paraná, with higher levels of phenolics, methylxanthines, and antioxidant activity. The supervised methods, soft independent modeling of class analogy (SIMCA) and partial least squares-discriminant analysis (PLS-DA), had similar predictability (≥75% of accuracy) in terms of classifying yerba mate according to different Brazilian regions. Therefore, the chemometric tools used in the current study was suitable to monitor and assess a large variation of the antioxidant composition of yerba mate from different southern Brazilian states.

The champignon mushroom has no antinutritional factors that can affect iron bioavailability. It is considered a functional food and can provide health benefits by presenting bioactive components. The simultaneous transfer of Na+, K+ and Fe2+ in the pre-cooked mushroom (Agaricus bisporus) was modeled and simulated by the finite element method (FEM). The Biot number, cross and main diffusion coefficients were determined by the super modified simplex optimization method by minimizing the percentage errors. The errors between experimental and simulated data were 5.66% for NaCl, 5.36% for KCl and 8.26% for Fe2+ in the static brine and 3.11% for NaCl, 3.30% for KCl and 15.34% for Fe2+ in stirred brine. With the obtained model, it was possible to verify the influence of the film formed on the surface of the mushroom during the diffusion of ions, as well as the increase of ferrous ion adsorption when using the salting system with stirring.

Abstract Encapsulation of bioactive compounds has been carried out to improve bioavailability and to protect them against harm conditions. However, encapsulation processes are often aggressive and it is important that encapsulated substances keep their biological activity. In this work curcumin was nanoencapsulated using dichloromethane as solvent and ultrasound as dispersion device. Nanoparticles were obtained using different curcumin concentrations and encapsulants (PLLA and Eudragit S100) and the encapsulation efficiency was inferred using spectroscopic and calorimetric techniques as well as optical microscopy. Total phenolic contents and antioxidant activity tests were applied to the curcumin before and after encapsulation and also to blank polymer nanoparticles. Results demonstrated that the encapsulation process had no deleterious influence on its antioxidant activity.

A relação de NaCl com problemas de hipertensão arterial tem levado a uma redução dos níveis de sal presente na produção de alimentos. O KCl tem sido usado como substituto parcial do NaCl, porque este não pode ser totalmente substituído sem afetar a aceitabilidade do produto final. Neste estudo, foi simulada a difusão que ocorre durante o processo de salga do ovo de codorna em salmoura estática e agitada. O modelo matemático utilizado teve como base uma generalização da segunda lei de Fick. O programa COMSOL Multiphysics foi usado para simular a difusão do sistema água-KCl-NaCl. Os desvios entre os dados simulados e experimentais foram de 2,50% para o NaCl e 6,98% para o KCl em salmoura estática, enquanto na salmoura agitada foram de 3,48% para o NaCl e 4,72% para o KCl. Os resultados da simulação apresentaram boa concordância com os valores experimentais e validando a capacidade preditiva do modelo proposto.

The relationship of NaCl with problems of arterial hypertension has led to a reduction in the levels of this salt in food production. KCl has been used as a partial substitute for NaCl since it cannot be completely substituted without affecting the acceptability of the end product. In this study, the diffusion that occurs during quail egg salting in static and stirred brine was simulated. The mathematical model used was based on a generalization of the Fick's 2nd law, and the COMSOL Multiphysics software was used to simulate the diffusion in the NaCl-KCl-water system. The deviations in the simulated data and experimental data were 2.50% for NaCl and 6.98% for KCl in static brine, while in the stirred brine they were 3.48% for NaCl and 4.72% for KCl. The simulation results presented good agreement with the experimental values and validated the predictive capacity of the model.

A substituição parcial do NaCl pelo KCl é uma alternativa promissora para produzir queijos com um teor reduzido de sódio, desde que não se altere sua qualidade final. Para assegurar uma proporção adequada dos sais, a utilização de modelos que simulam a difusão multicomponente durante a maturação de queijos com teor reduzido de NaCl é importante para o controle do processo e qualidade do produto. A segunda lei de Fick generalizada para dois solutos é um dos modelos mais utilizados para este fim, e o sistema de equações diferenciais resultante foi resolvido através do Método de Elementos Finitos (MEF). No presente trabalho, foi simulada a difusão dos sais NaCl e KCl durante a maturação de queijo prato utilizando uma salmoura estática 20% (m/m) contendo 70% de NaCl e 30% de KCl. Em seguida, os resultados estimados foram comparados com os dados experimentais. O desvio percentual obtido entre os dados experimentais e os estimados resultou em 4,43% para o NaCl e 4,72% para o KCl, indicando que o modelo proposto é válido para a produção de queijos de qualidade e com teor reduzido de sódio.

The partial replacement of NaCl by KCl is a promising alternative to produce a cheese with lower sodium content since KCl does not change the final quality of the cheese product. In order to assure proper salt proportions, mathematical models are employed to control the product process and simulate the multicomponent diffusion during the reduced salt cheese ripening period. The generalized Fick's Second Law is widely accepted as the primary mass transfer model within solid foods. The Finite Element Method (FEM) was used to solve the system of differential equations formed. Therefore, a NaCl and KCl multicomponent diffusion was simulated using a 20% (w/w) static brine with 70% NaCl and 30% KCl during Prato cheese (a Brazilian semi-hard cheese) salting and ripening. The theoretical results were compared with experimental data, and indicated that the deviation was 4.43% for NaCl and 4.72% for KCl validating the proposed model for the production of good quality, reduced-sodium cheeses.

The multilayer perceptron network was used to classify the gasoline. The main parameters used in the classification were established by the Ordinance nº 309 of the Agência Nacional do Petróleo, but without informing the network the legal limits of these parameters. The network used had 10 neurons in a single hidden layer, learning rate of 0.04 and 250 training epochs. The application of artificial neural network served classify 100% of the commercialized gas in the region of Londrina-PR and to identify the tampered gasoline even those suspected of tampering.

Water loss and sugar gain were modelling during the osmotic dehydration process of pieces of pineaplle. The transfer of solute to the fruit and the water to the solution was based on Fick's 2nd law. The three dimensional model was solved by the finite element method with the usage of the software COMSOL Multiphysics 3.2. The main and cross diffusion coefficients and the Biot number were determined on the simulation and the deviation between the experimental and the simulated data were 4,28% to sucrose and 1,66 to the water.

A relação entre o NaCl e a hipertensão arterial tem estimulado a sua substituição parcial por KCl em queijos. Entretanto, para manter a qualidade final do produto, é de suma importância assegurar uma proporção adequada de NaCl/KCl, bem como a distribuição homogênea destes sais. Os modelos que estimam a concentração salina, portanto, são valiosas ferramentas para o controle de qualidade. Para simular a difusão multicomponente durante a salga em salmoura estática, foi proposto um modelo unidimensional, baseado na solução analítica da 2ª lei de Fick generalizada para dois solutos. A solução analítica, implementada através de um algoritmo computacional, permitiu o ajuste dos coeficientes de difusão e a avaliação da resistência externa. Os resultados da simulação obtidos apresentaram boa concordância com os valores experimentais (desvio de 2,7% para o NaCl e 6,6% para o KCl), validando a capacidade preditiva do modelo proposto. Além disso, a simulação pode permitir um ajuste de ganhos de produtividade (redução do tempo de salga) através da estimativa do tempo de salga para teores salinos desejados.

The relation between NaCl and arterial hypertension has stimulated a partial substitution for KCl on cheese. However, it is very important to guarantee an adequate proportion of NaCl/KCl, and also the homogeneous distribution of these salts, to maintain the final quality of the product. Therefore, the models that calculate the salty concentration are useful tools to control the quality. In this study an analytic resolution of Fick's 2nd law, generalized for two salts, was used to simulate the salting in stationary brine. The analytic resolution, carried out through a computer program, allowed an adjustment of the diffusion coefficients and to evaluate the external resistance. The results calculated show a close comparison of the experimental values (an deviation of 2.7% to NaCl and 6.6% to KCl), validating the proposed model. The simulation can be used to adjust productivity (reducing the salting time) through the salting-time calculation for a required saltiness.