Optimization of the Production of α-LRhamnosidase by Aspergillus niger in Solid State Fermentation Using Agro-Industrial Residues.

The enzyme α-L-rhamnosidase specifically cleaves terminal rhamnose residues from a wide variety of natural products. This property endows this enzyme with important biotechnological potential as L-rhamnosidase could be employed in a variety of applications, including removing bitterness from citrus fruit juices, improving the aroma of wines and converting clinically important steroids. This work optimized α-L-rhamnosidase solid-state fermentation production from Aspergillus niger 426 using statistical methods. Firstly, a statistical mixture-design with three components to determine the best ratio of nutrients for enzyme production was carried out. The optimal conditions consisted of growing the fungi in media containing 0.14 g of cane sugar bagasse, 1.25 g of soybean hulls and 3.05 g of rice straw; these conditions achieved a maximum α-L-rhamnosidase activity of 1.92 U / mL. Next, a 3² Box-Behnken design to optimize culture moisture levels and nutrient solution pH values for enzyme production was carried out. α-L-rhamnosidase activity increased to 3.02 U / mL when medium moisture was 75.5% and pH value of 4.0.

Osmo-dehydrated functional product containing fructo-oligosaccharides: physical, chemical and sensorial characteristics

The objective of the present study was to develop a functional product from the osmo-dehydrated Fuji apple incorporating FOS with acceptable physical, chemical and sensorial characteristics and potential for commercial-scale production. Some treatments were discarded due to texture and water activity that did not reach the desired quality parameters. The products submitted to the osmo-dehydration treatments presented a greater vitamin C loss. All the treatments obtained sensory scores of 6 in a 9 points scale for all the attributes, except the crispness, indicating good acceptance. The sensory scores and incorporated FOS quantities indicated that the osmo-dehydrated apple products have potential for commercial-scale production.

Optimizing dehydration of apples Malus Domestica with fructo-oligosaccharide incorporation

The objective of the present study was to study the effect of the variables of the osmotic dehydration process on sliced Fuji apples (Malus domestica) using a 2 x 3² factorial design. The variables studied in the apple slices were the pretreatment (blanching or acidification), the temperatures (30, 45 and 60ºC) and the FOS concentration (40%, 50% and 60% m/v) of the osmotic solution. There was no difference among the pretreatments for the water activity and titratable acidity. The slices pre-treated by the acidification presented less enzymatic browning (greatest luminosity L* value) combined with a greater soluble solid contents (thus, this treatment was selected). Treatments T4 (45ºC and 40% m/v) and T7 (60ºC and 40%m/v), using the acidification presented responses within the recommended standards and FOS were validated by the repetition.

Métodos de gradiente para otimização simultânea: estudo de casos de sistemas alimentares / Gradients methods for simultaneous optimizations: case studies for food systems

Este trabalho teve como objetivo desenvolver um aplicativo com métodos de gradiente eficazes na otimização de sistemas alimentares com respostas múltiplas utilizando as funções de Derringer & Suich, incluindo um polinômio de 4º grau para a remoção das descontinuidades dessas funções. O aplicativo foi testado em três sistemas alimentares selecionados na literatura especializada: 1) inativação da lipoxigenase e lípase preservando-se a atividade da fitase durante o processamento hidrotérmico da cevada; 2) otimização simultânea das respostas na formulação de misturas de proteínas; 3) otimização simultânea dos parâmetros de torração de gérmen de milho visando aplicação como ingrediente em alimentos. O programa desenvolvido mostrou ser eficiente e confiável para a otimização em sistemas alimentares multirresposta

Difusäo do cloreto de sódio no processo de maturaçäo de queijos: modelagem matemática com o emprego do método de elementos finitos / The sodium chlorid diffusion during cheese ripening: matematical model applyng the finite element method

Solute (sodium chloride) transference through a three-dimensional matrix, during cheese ripening, was studied applying the finite element method (MEF). The variational formulation 9Galerkin) of the differential problem (diffusion model) had as the theoretical basis Fick's second law. The methods for time integration were developed according to Crank-Nicolson (central difference), and modified Euler (backward difference), which presented unconditional stability. The computational program proved to be versatile in solving sampling situations in realistic condition nd can be used in complex geometry. The application of numeric method (MEF) withmodified-Euler scheme in the simulation of diffusion of sodium chloride in the ripening, showed to be close to the values published in specialized literature

Determinaçäo do teor de nitrato em vegetais da regiäo de Londrina por complexaçäo do ácido salicílico / Dtermination of nitrate proportion in vegetables of Londrina region by complexation of salicylic acid

Foi avaliado o método de análise de nitrato por complexaçäo do ácido salicílico e realizada a determinaçäo do teor de nitrato em amostras de couve, espinafre, almeiräo, rúcula e chicória recolhidas em feiras livres da cidade de Londrina