The brewing waste, also known as trub, is an abundant by-product of the brewing industry. Such material presents high levels of phenolic compounds, which promote antioxidant, antimicrobial and antifungal effects, turning the trub economically attractive. In this study, the trub’s phenolic compounds were extracted by ultrasound-assisted extraction technology. Such experiments were conducted according to a central composite rotatable design (CCRD), with the evaluated parameters being ethanol concentration, solid-liquid ratio and extraction temperature. Response surface methodology (RSM) described the effect of process’ variables through second order polynomial models, adjusted appropriately for such analysis, and optimized the operating conditions, aiming to obtain the maximum extraction of phenolic compounds through the proposed technique. The extraction’s optimal conditions for the evaluated variables were ethanol concentration of 58%, solid-liquid ratio of 1 g per 32 mL, and extraction temperature of 36 ºC, during a 30 minute process. Considering such experimental conditions, the total amount of phenolic compounds was equal to 7.23 mg of gallic acid g-1 trub, indicating that a great concentration of phenolic compounds can be extracted from this material through the proposed technique. Thus, this indicates that trub might be a promising by-product that can be used in different industrial fields.

Micropartículas de poli(3-hidroxibutirato) (PHB) contendo cetoprofeno (KET) como fármaco modelo foram preparadas através da técnica de emulsão-evaporação do solvente O/W. Com o intuito de atribuir uma barreira adicional à liberação do cetoprofeno, micropartículas de KET/PHB foram revestidas por um filme de quitosana através da técnica spray drying. O filme de quitosana foi reticulado com glutaraldeído ou genipin. A eficiência de encapsulação, 60%, foi da mesma ordem de grandeza para todas as formulações de micropartículas estudadas. A influência das concentrações de quitosana e do agente reticulante (glutaraldeído e genipin) na quantidade de cetoprofeno liberado após 1 h, e sobre o prolongamento de liberação em 72 h, foi avaliada através de análises estatísticas, indicando que ambas as variáveis influenciaram as respostas. A liberação do cetoprofeno a partir de micropartículas compostas recobertas com quitosana reticulada foi lenta e sustentável, sendo um transportador polimérico muito promissor para a libertação de fármacos.

The purpose of this study was to prepare composite microparticles of poly(3-hydroxybutyrate) (PHB) containing the drug ketoprofen (KET) coated with a layer of crosslinked chitosan (CHI) for application as a controlled drug-release system. Microparticles of PHB containing KET as a model drug were prepared using the emulsion-solvent evaporation technique, and coated with a film of chitosan by spray drying to obtain the composite microparticles. The surface film was modified using glutaraldehyde or genipin as the crosslinking agent. The KET encapsulation efficiency of the PHB microparticle was 60%, and the same value was obtained after inclusion of the CHI film by the spray drying process. The influence of the concentration of chitosan used to obtain the composite microparticles and the crosslinking agent on the amount of drug released after 1 and 72 h was evaluated by statistical analysis, and both variables were found to affect the responses. The drug release from the composite microparticles coated with crosslinked chitosan was slow and sustainable, indicating that this represents a very promising polymeric carrier for drug delivery.

Neste artigo, as propriedades emulsificantes da proteína isolada de soja (SPI) foram evidenciadas mostrando que estas macromoléculas sofrem mudanças conformacionais quando adsorvidas em interfaces. Investigou-se a conformação das cadeias proteicas ancoradas nas regiões interfaciais de emulsões de óleo em água (o/a) através de técnicas de espalhamento de raios X (SAXS) e de imagem (microscopia eletrônica de varredura (SEM)). O valor médio do raio de giro (Rg) da SPI (aq) é 20 nm e aumenta para 30 nm em emulsões o/a; as proteínas atuam como moléculas anfifílicas expondo seus núcleos hidrofóbicos ao óleo e os resíduos hidrofílicos à fase aquosa. Este valor ainda é maior após o spray drying das emulsões, na interface o/ar das respectivas microcápsulas. As paredes das microcápsulas são fractais de objetos agregados com superfícies rugosas, que são alisadas pela presença de um agente de reticulação.

Herein, the emulsifying properties of soy protein isolate (SPI) were highlighted by showing that the macromolecules undergo conformational changes when adsorbed at interfaces. The conformation of protein chains nested at the interfacial region of oil in water (o/w) emulsions by means of X-ray scattering (SAXS) and direct imaging (scanning electron microscopy (SEM)) techniques was investigated. The mean radius of gyration (Rg) for SPI (aq) is 20 nm and increases up to 30 nm in o/w emulsions; the proteins act as amphiphilic molecules by exposing their hydrophobic core to the oil and their hydrophilic amino acid residues to the water phase. By spray drying the emulsions, it was also possible to measure the size (Rg = 40 nm) and to evaluate the morphology of these proteins at the oil/air interface of the respective microcapsules. The walls of microcapsules are fractals of clustered objects with rough surfaces, which are smoothed by the presence of a cross-linking agent.

The dispersion of carbon nanotubes in water for their utilization in nanoscale devices is a challenging task. Comparative studies on interaction and dispersion of multi-wall carbon nanotubes (MWNT) using two different surfactants (sodium dodecyl sulfate, SDS, and polyoxyethylenesorbitanmonooleate, Tween 80) are presented. The interaction between carbon nanotubes and surfactants was studied by tensiometry, conductivimetry, and fluorimetry. The dispersions of MWNT in surfactants were characterized using a UV-vis spectrophotometer. For effective dispersion, the minimum weight ratio of MWNT to surfactant was 1:41 and 1:3 for SDS and Tween 80, respectively.