Effect of enzymatic treatment on tannins and phytate in sorghum (Sorghum bicolor) and its nutritional study in rats

Sorghum is a cereal used as a food source by humans and animals. However, it presents antinutritional factors such as tannins and phytic acid, compounds that form complexes with proteins and minerals, respectively, decreasing sorghum’s digestive value. The purpose of this study was to apply tannase and phytase to sorghum and evaluate the effect on tannins and phytate level and the effect of the enzymatic treatment on Wistar rats. Tannin sorghum was treated with tannase and phytase, the effect of this treatment was measured in a study with rats, a group received a diet with raw sorghum and the other one a diet with treated sorghum. The enzymatic treatment was effective in reducing tannins and promoting the increase of inorganic phosphorus. The biological assay showed that the enzymatically treated sorghum was better than raw sorghum in the apparent digestibility of phosphorus, in the level of glucose, cholesterol and triacylglycerol. Treatment of the sorghum also resulted in lower activity of the enzymes aspartate aminotransferase and alanine aminotransferase in rat serum. The enzymatic treatment of sorghum could improve the nutritional value of this cereal while also decreasing environmental pollution.     

An Unexpected Pressure Effect in the Catalytic Hydrogenolysis of a Complex Benzyl Amine

The selective hydrogenolysis of a complex benzylamine containing a pyridone ring and aryl fluorides was investigated. The aim of the research was to find a catalyst and reaction conditions under which the complete hydrogenolysis of the benzylamine could be accomplished with no aryl fluoride cleavage nor pyridone hydrogenation observed. This objective was accomplished by use of a specific 10 % Pd/C catalyst in a THF/EtOH solvent at 40 °C. It was found that as the H₂ pressure decreased the amount of debenzylated amine increased because of the decrease in pyridone hydrogenation. Unexpectedly, though, the rate of hydrogenolysis also increased with decreasing H₂ pressure. A rationale for this observation is presented.

     

Ni/CeO2–MgO catalysts supported on stainless steel plates for ethanol steam reforming

Ni/CeO₂–MgO catalysts on powder form and supported on stainless steel plates were prepared, characterized and tested towards hydrogen generation via the steam reforming reaction of ethanol. The structured catalyst was prepared by the dip-coating technique. The coatings obtained over the stainless steel plates were homogeneous and retained their integrity after the reaction experiences. The samples were characterized by SEM, TEM, XRD, ICP-AES, TPR, OSC and N₂ adsorption–desorption measurements. Catalysts presented very good stability under reaction conditions for 16 h on-stream, without showing a significant variation in the activity or product distribution. The structured catalysts presented similar activities and selectivities respect to those of the powder, whereby the deposition method did not modify the catalytic properties of the particulate material. The presence of the AISI 430 stainless steel substrate also had not a significant influence on the performance of the deposited material.     

Lactose-free skim milk and prebiotics as carrier agents of Bifidobacterium BB-12 microencapsulation: physicochemical properties,survival during storage and in vitro gastrointestinal condition behaviour

Bifidobacterium BB-12 was microencapsulated by spray drying using lactose-free milk, lactose-free milk and inulin, and lactose-free milk and oligofructose, resulting in powders 1, 2 and 3, respectively. The highest encapsulation yield (88.01%) and the highest bifidobacteria viability during 120 days of storage were noted for spray-dried powder 2. Spray-dried powders 1 and 3 show a higher tendency to yellow colour. After being submitted to in vitro-simulated gastrointestinal conditions, the best probiotic survival rate result was found for spray-dried powder 3 (87.59%). Therefore, spray-dried powders containing prebiotics were the most appropriate combinations for microencapsulation of Bifidobacterium BB-12 and maintenance of cell viability during storage and gastrointestinal system, showing great potential to be used in lactose-free dairy products.     

Influence of Temperature,Air Velocity,and Ultrasound Application on Drying Kinetics of Grape Seeds

The objective of this work was to determine the influence of temperature, air velocity, and ultrasound application on the drying kinetics of grape seeds. The drying kinetics were determined at 1.0, 1.5, 2.0, and 3.0 m/s and at 40, 50, 60, and 70°C. At 1.0 and 1.5 m/s, the experiments were carried out with and without ultrasound application. To establish the influence of the variables on the drying kinetics, the results were modeled by means of both the Peleg and a diffusion model. The activation energy was determined (Arrhenius' equation). For an air velocity of over 1.5 m/s, it was determined that the external resistance to mass transfer was negligible. No influence of ultrasound application was observed, probably due to the fact that grape seeds are very hard and have a low level of porosity.     

Antibacterial Activity of New Oxazolidin-2-One Analogues in Methicillin-Resistant Staphylococcus aureus Strains

Staphylococcus aureus is one of the most common causes of nosocomial infections. The purpose of this study was the synthesis and in vitro evaluation of antimicrobial activity of 10 new 3-oxazolidin-2-one analogues on 12 methicillin resistant S. aureus (MRSA) clinical isolates. S. aureus confirmation was achieved via catalase and coagulase test. Molecular characterization of MRSA was performed by amplification of the mecA gene. Antimicrobial susceptibility was evaluated via the Kirby-Bauer disc diffusion susceptibility test protocol, using commonly applied antibiotics and the oxazolidinone analogues. Only (R)-5-((S)-1-dibenzylaminoethyl)-1,3-oxazolidin-2-one (7a) exhibited antibacterial activity at 6.6 μg. These results, allow us to infer that molecules such as 7a can be potentially used to treat infections caused by MRSA strains.     

Low-temperature processing of thin films based on rutile TiO2 nanoparticles for UV photocatalysis and bacteria inactivation

Using a low-temperature, simple, and economic processing technique, TiO₂ nanoparticles (rutile phase) are immobilized in an inorganic matrix and then deposited on glass for bacteria inactivation in water. Using this low thermal budget method (maximum processing temperature of 220 °C), thin films of immobilized TiO₂ nanoparticles are obtained so that practical water decontamination after UV radiation is possible by avoiding the additional step of catalyst separation from treated water. In order to validate the photocatalytic activities of these TiO₂ nanoparticles (prepared as thin films), they were tested for bacteria inactivation in water under UV–A radiation (λ > 365 nm), while extensive characterizations by dynamic light scattering, X-ray diffraction, ultra violet–visible absorption spectroscopy, fourier-transform infra red spectroscopy, and profilometry were also carried out. Despite previous reports on the low or lack of photocatalytic activity of rutile-phase TiO₂, inactivation of Escherichia coli in water was observed when thin films of this material were used when compared with the application of UV radiation alone. Physical characterization of the films suggests that size and concentration-related effects may allow the existence of photocatalytic activity for rutile-TiO₂ as long as they are exposed under UV–A radiation, whereas no effect on bacteria inactivation was observed for thin films in the absence of TiO₂ or radiation. In brief, a low thermal budget process applied to thin films based on TiO₂ nanoparticles has shown to be useful for bacteria inactivation, while possible application of these films on widely available substrates like polyethylene terephthalate materials is expected.