• Energy Research
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Inhibition from migration of plastic ingredients such as styrene monomer (SM) is very important in food packaging industry. Styrene monomer is one of the substances which can potentially migrate from polystyrene based packaging. In the present study, organoclay and zinc oxide nanoparticles (ZnO-NPs) were used for decreasing of the SM migration into food simulants (10 and 50% ethanol (v/v)). A used GC-FID method for measuring of the migrated SM showed good precision and accuracy. Maximum reduction of SM migration into 10% and 50% ethanol (24 h storage at 40 °C) were observed in the polystyrene/nanoclay and polystyrene/ZnO samples, respectively. The SM migration data in 50% ethanol at 5 °C followed from Fickian diffusion law and the lowest diffusion coefficient (2.89 × 10-14 cm2/s) was observed in the polystyrene/ZnO/nanoclay samples.

In this work, a four-factor five-level full factorial central composite design (CCD) was used to optimize the ultrasound-assisted extraction (UAE) of saffron major components, namely picrocrocin, safranal and crocin. The process parameters included ethanol concentration (0-100%), extraction time (2-10 min), duty cycle (0.2-1.0) and ultrasonic amplitude (20-100%). The extracted compounds were measured both by spectrophotometry and chromatography techniques. The results revealed that the middle concentrations of ethanol and relatively long process durations along with high duty cycles and ultrasonic amplitudes had the most profound impact on the yields of the extracted bioactives. UAE was optimized using response surface methodology (RSM) and artificial bee colony (ABC); a comparison between these methods indicated their optimization power was approximately the same. According to the RSM analysis, an ethanol concentration of 58.58%, extraction time of 6.85 min, duty cycle of 0.82 and amplitude of 91.11% were the optimum extraction conditions, while the optimal conditions resulting from ABC were 53.07%, 7.32 min, 0.93 and 100% for the UAE variables respectively. Finally, HPLC analysis was carried out on the UAE optimum extract resulting from RSM. Four crocetin esters were detected in the optimal extract.

In the present work Principal Component Analysis applied to (1)H NMR spectra of balsamic and traditional balsamic vinegars is used to establish a simple and rapid aging determination protocol. Chemical composition of vinegar is dominated by carbohydrates even though several small components can be clearly observed in the proton NMR spectrum. Quantitative determination of some selected metabolites such as ethanol, acetic acid, malic acid, glucose, and HMF, considered as potential aging indicators, has been performed. (1)H NMR spectroscopy provides noninvasive characterization of such compounds, and our data demonstrate the validity of this approach, giving very promising results for assessing the quality of the final product.

Microemulsions are thermodynamically stable systems that have attracted considerable attention in the food industry as delivery systems for many hydrophobic nutrients. These spontaneous systems are highly dependent on ingredients and composition. In this work phase diagrams were constructed using two surfactants (Kolliphor RH40 and ELP), water, sunflower oil, and ethanol as cosurfactant, evaluating their physicochemical properties. Stability of the systems was studied at 25 and 60 °C, monitoring turbidity at 550 nm for over a month to identify the microemulsion region. Conductivity was measured to classify between water-in-oil and oil-in-water microemulsions. The phase diagram constructed with Kolliphor RH40 exhibited a larger microemulsion area than that formulated with Kolliphor ELP. All formulations showed a monomodal droplet size distribution with low polydispersity index (<0.30) and a mean droplet size below 20 nm. Systems with higher water content presented a Newtonian behavior; increasing the dispersed phase content produced a weak gel-like structure with pseudoplastic behavior under flow conditions that was satisfactorily modeled to obtain structural parameters.

A procedure is described that allows the rapid determination of ethanol in a wide variety of alcoholic beverages. Dynamic headspace analysis is employed and a fuel cell sensor is used for the quantitative determination of ethanol. The method is rapid and compares favourably in accuracy with distillation and gas-chromatographic procedures.

A theoretical model for simulation of conventional steam-heated cylinder dryers is developed by considering the heat and mass transfer in a porous sheet during drying. Expressions for sheet shrinkage as a function of mass of water removed and for reductions in sheet porosity are derived for inclusion in the model. The interface thermal contact conductance of moist paper handsheet/metal interfaces has been experimentally investigated. A resulting empirical correlation, representing the thermal contact conductance between the cast iron dryer surface and paper web, is incorporated into the drying simulation model to reflect reductions in heat input to the sheet during drying. Finite difference techniques are used to obtain the numerical solutions. Average sheet moisture content and temperature along the length of the dryer section as well as average evaporation rates per cylinder are predicted by the model. Consideration of the internal dynamics of the drying process allows profiles of sheet moisture content, temperature, liquid flux, and vapor flux through the sheet thickness to be developed throughout the dryer section. Drying results are consistent with actual production cases. The model can be used to design dryer sections, study changes in operating conditions or in layout of a multi-cylinder dryer, or simulate the application of enhanced drying devices to a conventional drying section. The effect of the drum/paper contact conductance on drying rates and resultant dryer section requirements is provided as an example application of the model.

Abstract A novel approach to the intensification of renewable and sustainable production of photoautotrophic ethanol from microalgae was investigated using periodic ultrasonication. The effect of utilizing ultrasonic pulsing during ethanol production using a metabolically engineered ethanol producing cyanobacterium Synechocystis PCC6803 strain NAV001 was analysed with an ultrasonic frequency of 20 kHz. Ultrasonic treatment resulted in enhancement of ethanol yields. The ethanol yield was found to be higher when ultrasonic pulsing was initiated during the exponential phase of growth. The optimum ultrasonic conditions for enhanced yield of ethanol within this model system was found to be 30 °C, 15% of power input (97.5 W) and 10 min pulse time. The cytotoxic effect of ultrasonic pulsation was investigated by analysing the survival percentage and auto-fluorescence of the cyanobacterium via imaging by confocal laser scanning microscopy. The overall effect of ultrasonic dose on ethanol production and growth rate of microalgae was analysed by using Haldane inhibition kinetics.