Electrical Conductivities of Liquid Egg Products and Fruit Juices Exposed to High Pulsed Electric Fields

Electrical conductivity can be used to monitor important changes in a food product during pulsed electric field (PEF) processing. Electrical conductivities of selected fruit juices (namely apple, orange, and pineapple juices) and liquid egg products (namely whole egg, yolk, and egg white) were determined online during a PEF treatment. The property was measured at broad processing temperatures ranging from 5 to 55°C. Electrical conductivity increased linearly with increasing temperatures for all the products. The liquid egg products have the highest overall electrical conductivity varying from 0.22 to 1.1 S/m whereas fruit juice products have the lowest electrical conductivity ranging from 0.13 to 0.63 S/m. Regression equations of electrical conductivity as functions of temperature were developed. This paper provides a database and equation correlations of food electrical conductivity that could be used to design and optimize PEF process.     

Characterization of paper mill sludge as a renewable feedstock for sustainable hydrogen and biofuels production

Paper and pulp mills generate substantial quantities of cellulose-rich sludge materials that are disposed in landfills at a large scale. For sustainability purposes, sludge materials can be bioprocessed to produce renewable fuels and useful chemicals. The enzymatic hydrolysis of cellulose is the process bottleneck that affects the conversion economics directly by using zero-cost raw materials. In order to study and optimize the process, the characteristics of the sludge raw materials should be first evaluated. In this work, sludge samples were obtained from paper mills located at different locations in Wisconsin and Minnesota. Part of the sludge samples was washed (de-ashed) with hydrochloric acid while the other part remained unwashed. The samples were subjected to multiple spectroscopic analyses techniques to evaluate the morphological properties of cellulose fibers and to estimate the total structural carbohydrate content. The results showed that the de-ashing process changed some fiber characteristics and cellulose crystallinity structure in all sludge samples. Sludge sample A (obtained from Kraft pulp and recycled paper mill region) showed a high percentage of fiber, with crystalline cellulose, compared to the other two sludge samples suggesting that sludge A is a valuable source to make value-added products. Aspen Plus mass and energy calculations performed in view of the ‘zero’ cost and the reliable supply of sludge raw materials producing 2 mol H₂/mol glucose. Moreover, the results showed that extracting crystalline cellulose from these sludge samples is more profitable than crystalline cellulose made from the other lignocellulosic feedstocks. The results reported here showed that the utilization of these sludge materials would be an economically attractive and promising alternative for the production of hydrogen.     

Chemical composition and antioxidant activity of oil from wild Achillea setacea and A. vermicularis

The objective of this study was to determine and compare the composition of volatile components of two species, A. setacea and A. vermicularis, under the temperate climatic conditions (north of Iran) and to investigate quantification of fatty acids in the oil extracted using gas chromatography-flame ionization detector and to evaluate the antioxidant potential and the phytochemical profile in terms of phenolic acids and flavonoids content of the oils obtained from the plants. Gas chromatography-mass spectrometry analysis of the essential oils showed that the major compounds of A. setacea were nerolidol (20%) and α-cubebene (14%), while in A. vermicularis were camphor (15%) and borneol (13%). Oil analysis revealed that the major components were palmitic and myristic acids. Chromatographic separation of their phenolic compounds (high-performance liquid chromatography) demonstrated that sinapic, gallic, caffeic, vanillic, syringic, and ferulic acids were present in the two oils of the plants, but in different amounts. These results confirmed A. setacea and A. vermicularis as important sources of bioactive metabolites.     

Sensory and quality parameters of raw and processed Chicory-Hindbeh,a commonly consumed dark leafy green in Lebanon (Cichorium intybus L.) during frozen storage

This work aimed at assessing the effect of heat treatment and frozen storage on the sensory and chemical properties of chicory with the goal of optimizing the heat pretreatment-storage condition to best preserve the chemical and sensory properties of chicory. Raw, boiled (10 min), blanched (90 °C for 60 s) and steamed (for 20 s) chicory samples were produced and stored at −6 °C, −12 °C or −18 °C for 4 months. Chemical analyses (moisture, ash, vitamin C, peroxidase activity, chlorophyll and color) and sensory evaluation (QDA and hedonic evaluation) were conducted. Treatment significantly influenced all chemical variables (p < 0.001), except for moisture; and so did freezing temperatures for a-value (p < 0.001), chlorophyll-a, peroxidase activity, vitamin C and ash (p < 0.01), total chlorophyll, moisture and b-value (p < 0.05). Differences were obtained for age for all chemical variables (p < 0.001). Treatments affected consumers' acceptability of chicory and QDA showed that boiled chicory was significantly more tender, less chewy and crunchy and needed less time to disintegrate than other samples. PCA showed that PC1 and PC2 separated attributes based on type and intensity of treatments, respectively. It is recommended to use blanching at 90 °C for 60 s and freezing at −12 °C or −18 °C to best preserve the quality of chicory.     

Cane molasses fermentation for continuous ethanol production in an immobilized cells reactor by Saccharomyces cerevisiae

Sodium-alginate immobilized yeast was employed to produce ethanol continuously using cane molasses as a carbon source in an immobilized cell reactor (ICR). The immobilization of Saccharomyces cerevisiae was performed by entrapment of the cell cultured media harvested at exponential growth phase (16 h) with 3% sodium alginate. During the initial stage of operation, the ICR was loaded with fresh beads of mean diameter of 5.01 mm. The ethanol production was affected by the concentration of the cane molasses (50, 100 and 150 g/l), dilution rates (0.064, 0.096, 0.144 and 0.192 h^?1) and hydraulic retention time (5.21, 6.94, 10.42 and 15.63 h) of the media. The pH of the feed medium was set at 4.5 and the fermentation was carried out at an ambient temperature. The maximum ethanol production, theoretical yield (Y_E/S), volumetric ethanol productivity (Q_P) and total sugar consumption was 19.15 g/l, 46.23%, 2.39 g l^?1 h^?1 and 96%, respectively.     

Numerical simulations of non-premixed turbulent combustion of CH4–H2 mixtures using the PDF approach

The present work is devoted to the study of non-premixed turbulent combustion with the PDF approach using three turbulence models: k-? model, modified k-? model and RSM model. A detailed kinetic mechanism is used in the numerical simulations. The three turbulence models are compared and evaluated with the experimental data and the numerical results of the literature. The evaluation concludes that the modified k-? is the most appropriate for simulating this kind of flame. A study of the effect of hydrogen addition on methane combustion is performed. Hydrogen addition causes the elevation of combustion temperature, the decreasing of CO and CO₂ mass fractions but leads to the increase of NO mass fraction.     

Hydrogen production from human and cow urine using in situ synthesized aluminium nanoparticles

Hydrogen production from wastewater system has the potential to add a new dimension to the energy economy. Urine is an abundant waste and contains about 90–96% of water. While there have been efforts to generate electricity from urine (using microbial fuel cells), direct hydrogen production from urine using any technique is less explored. We report human and cow urine pretreatment with simultaneous hydrogen production using a simple redox reaction. This is achieved via in situ formation of aluminium nanoparticles in urine through reduction of aluminum salt using sodium borohydride; the key novelty of the process is the use of Al salt/NaBH₄. The in situ prepared aluminium nanoparticles instantly react with urine to produce hydrogen. The volume of hydrogen produced is observed to be sensitive to pH, amount of Al salt, and ageing (storage time of urine). Interestingly, ageing does not impact the kinetics of initial hydrolysis in cow urine as much as it affects in the case of human urine. Fresh urine is found to be better in both the cases. Total carbon, total organic carbon, total nitrogen and total phosphorus removal efficiencies are found to be a maximum of 69.93%, 71.88%, 64.16% and 50.9% respectively for human urine; these values are 67.8%, 70.1%, 61.3% and 48.9% for cow urine at pH 3.     

On Analytic Continuation of Solutions of Linear Partial Differential Equations

We study analytic continuation properties of solutions of linear partial differential equations of Cauchy–Kowalewski type, with respect to one complex variable in sectors of infinite radius. Growth estimates are also investigated. 2000 Mathematics Subject Classification. 35C10, 35C20.