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Transformation of biomass into renewable energy products is currently one of the most promising technologies for dropping dependence on fossil fuels. Biodiesel production may improve with the use of heterogeneous catalysts, such as zeolites. In this work, computational calculations in conjunction with thermal analysis (TGA), evolved gases analysis (EGA) and IR spectroscopic studies were used in order to obtain a more detailed information on the adsorption mechanism involved in the rate-determining step of esterification reactions inside the H-ZSM-5 zeolite. ATR-FTIR spectra showed a molecular adsorption of MeOH and acetic acid (AcOH) on the H-ZSM-5 surface, IR spectrum of AcOH showed perturbations in the region of the bands relative to the carbonyl group C=O, indicating molecular interactions by the adsorption processes, as predicted by theoretical calculations. Adsorption of a single molecule of AcOH by C=O in a single adsorption step followed by coadsorption of MeOH is more stable than adsorption involving the zeolite proton sharing, however energies values suggested competitiveness between both mechanisms. Interactions between the adsorbed molecules and the lattice structure are crucial in controlling the adsorption observed experimentally.

Objective The influence of broiler carcass scalding conditions on chicken breast meat quality parameters was investigated. Methods Two hundred and seventy Cobb broiler chickens from 42 to 48 days old were slaughtered according to the standard industry practice and scalded in five temperature/time combinations—T 1 , 54°C/210 s; T 2 , 55°C/180 s; T 3 , 56°C/150 s; T 4 , 57°C/120 s; T 5 , 58°C/90 s. Results Scalding temperature increase resulted in higher values of external and ventral lightness and in protein functionality reduction—determined by emulsification capacity and protein denaturation—in chicken breast fillets 24 h post-mortem . Protein secondary structures had conformational changes, with a decrease of the α-helix and an increase of the β-sheet and β-turn proportions, mainly in T 1 and T 5 samples, determined by Fourier-transform infrared spectroscopy in an attenuated reflectance mode analysis. The chemical composition, pH, water holding capacity and Warner-Bratzler shear force did not differ among the treatments. In the fatty acid profile, the 18:1n-9 was lower in T 5 , which suggested that the high scalding-temperature could have caused the lipid oxidation. The values of the polyunsaturated fatty acids (PUFA), such as 22:2, 20:4n-6, and 22:6n-3, were highest in the T 5 , thus being related to the phospholipid cellular membrane collapse in this experimental condition and subsequent release of these PUFA. Conclusion Intermediate scalding-parameters avoided the negative changes in the chicken meat quality.

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The niobium pentoxide (Nb 2 O 5) is a semiconductor capable of prevent the efficiency loss by recombination in dye sensitized solar cells (DSSC) given the high energy gap. The aim of this study is to investigate the performance of DSSC containing Nb 2 O 5 obtained by Pechini method and hydrothermal synthesis, mixed with TiO 2 nanoparticles. The characterization techniques used were X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DSL) and potentiodynamic polarization under power light incidence of 100 mWcm-2. XRD confirmed obtaining orthorhombic structure niobium pentoxide tested for both methodologies, the SEM showed the best distribution of the oxide obtained by hydrothermal synthesis efficiency was calculated from the current density-potential curves (j-v) confirming the higher efficiency for this sample, about 20% higher.

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