Layer-by-layer self-assembly of multifunctional enzymatic UF membranes

In order to eliminate membrane fouling and to ensure enzymatic hydrolysis of urea, multifunctional biocatalytic membranes were prepared by using urease (URE) and trypsin (TRY) enzymes on the sulfonated polysulfone (SPSf) ultrafiltration membrane via layer-by-layer (LbL) self-assembly method. The membrane architecture consisted of multilayer assembly with TRY and URE enzymes as the outer layer and inner sandwiched layer, respectively. Polyethyleneimine (PEI) and alginate (ALG) were used as cationic and anionic polyelectrolytes. Sulfonation and PEI deposition were successfully accomplished as confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC) and scanning electron microscopy analysis, contact angle measurements, staining with toluidine blue and Congo red dyes and dead-end filtration experiments. A characteristic value of SPSf membrane with a high water permeability (1000 L/m².h.bar) and 95% bovine serum albumin (BSA) rejection was observed. In static conditions, URE activities of SPSf2-PEI-URE membrane were not affected by BSA fouling, while TRY immobilizations with increased concentrations (SPSf2-PEI-URE-PEI-ALG-TRY) significantly lowered the activity of URE. In dynamic conditions, each deposited layer exhibited individual resistance to flow that can be considered as irreversible fouling and caused 90% of flux decline for the SPSf2-PEI-URE-PEI-ALG-TRY membrane assembly. The recovery of the initial flux for the multilayered membrane at the end of six fouling and washing cycles was observed 85%. Moreover, at the end of 5 cycles, 78% of the URE initial activity of the multilayered membrane was preserved. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48750.     

A new classification approach for prediction of flyrock throw in surface mines

Bulletin of Engineering Geology and the Environment - A novel classification approach was proposed for prediction of flyrock throw distance based on the site measurements performed in a sandstone...     

The influence of binder content on the water transport properties of waterborne acrylic paints

Diffusion coefficients and sorption isotherms of water in waterborne acrylic paint films and in the pure binder of the paints have been measured by gravimetric sorption. Solubility of water was found to enhance with the increased binder content in the paint films while the diffusivity of water decreased significantly. Sorption isotherms in the paint and pure copolymer films were correlated with the Flory Huggins theory and ENSIC model, respectively. Fickian diffusion was observed in both types of films and the kinetic data were best correlated with a numerical model which takes into account the concentration dependency of the diffusion coefficient and the dimensional change of the film due to sorption. It was concluded that the utilization of a simplified analytical solution may lead to significant errors in the estimation of diffusivities.     

Influence of fat content and emulsifier type on the rheological properties of cake batter

The effects of fat content and emulsifier type on the rheological properties of cake batter have been investigated by using a parallel-plate rheometer. The apparent viscosity of cake batter with five different fat concentrations (0, 12.5, 25, 37.5, and 50%) and two types of emulsifier, namely Purawave and Lecigran, was studied as a function of the shear rate. In addition, the time dependency of different cake formulations was investigated. It was found that cake batter with different fat concentrations and emulsifier types exhibited shear thinning and time-independent behavior. Experimental data provided a good fit for the power law model. The increase in fat content and addition of emulsifier caused a decrease in the apparent viscosity. The flow behavior index was not found to be dependent on the composition of cake batter.     

Removal of copper(II) and cadmium(II) ions from aqueous solutions by biosorption onto pine cone

In this study, the removal of copper(II) and cadmium(II) ions from aqueous solutions by biosorption onto pine cone was studied. Variables that affect the biosorption process such as pH, biosorbent dosage, initial metal ion concentration, contact time and temperature of solution were optimized. Experimental data were fitted to Langmuir, Freundlich, Dubinin Radushkevich and Temkin isotherm models to investigate the equilibrium isotherms. Pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models were used to determine the biosorption mechanism. The thermodynamics of biosorption were studied for predicting the nature of biosorption. Experimental results showed that pine cone could be evaluated as an alternative precursor for removal of heavy metal ions from aqueous solutions, due to its high biosorption capacity, availability, and low cost.     

Halogen lamp–microwave combination baking of cookies

The effects of halogen lamp–microwave combination baking on the quality of cookies in terms of texture, color and spread ratio were studied. In addition, gelatinization and pasting properties of cookies baked in different ovens were assessed by using a Rapid Visco Analyzer. The hardness values of the cookies increased with increasing baking time and/or halogen power. The microwave power also contributed to cookie hardness. The lightness values of the cookies decreased, while the a* and E values increased linearly during baking at different halogen lamp and microwave powers. The spread ratio of conventionally baked cookies was significantly lower than that of the other cookies. Halogen lamp power, microwave power and baking time were found to have a significant effect on the spread ratio of the cookies. The moisture contents of the cookies decreased during baking as the halogen lamp and/or the microwave power level increased. The best baking condition in a halogen lamp–microwave combination oven to produce cookies having similar quality parameters as conventionally baked ones was baking at 70% halogen lamp and 20% microwave power levels for 5.5 min. The baking time of these cookies is half of that required in conventional baking.     

Gluten contamination in manufactured gluten-free foods in Turkey

ABSTRACT

Gluten contamination in manufactured gluten-free foods (mGFFs) is a major health, well-being and economic issue worldwide for both mandatory and voluntary GFF-consumers. Although scarce, a number of surveys have shown that up to 21.5 % of mGFFs in circulation in the market are contaminated with gluten. However, at the present time there is no published work reporting gluten contamination in mGFFs produced in Turkey. In this paper miscellaneous mGFFs produced in Turkey were analysed for gluten concentration (G) to fill this knowledge gap, and to compare the situation in Turkey with worldwide efforts on this issue. A total of 200 mGFFs from 8 product categories (snack, pasta, bread, cookie, cracker, farina, traditional and others), and manufactured using 7 main ingredients (cereal mixture, buckwheat, corn, rice, locust bean, potato, and others) were analysed. A significant portion of mGFFs (17.5 %) were contaminated with gluten and therefore unacceptable as being GFF. The results point to buckwheat as the main cause of this contamination. If buckwheat is excluded, the ratio of unacceptable mGFFs dramatically decreases to 6.3 % and probably to 1.8 %, which are comparable figures to those reported for other countries. Almost all countries are subjected to the same regulations on GFFs, and the problem of gluten contamination could readily be solved to a great extent if pre-market measures are mandated. Enforcing mGFF-producers to screen their raw materials and final products to detect the presence of gluten, and preventing the release of contaminated mGFFs into the market would be a practical measure in favour of all stakeholders involved in GFF-consumption.     

Effectiveness of chitosan‐based coating in improving shelf‐life of eggs

Despite eggs having a natural packaging—shell—they are perishable and can lose their quality during storage. Chitosan‐based coatings were applied to shell eggs to examine potential effects on egg quality properties (weight loss, Haugh unit, yolk index) during 4 weeks of storage. Mineral amounts in yolks were also evaluated after 4 weeks of storage. Three chitosan‐based coatings produced with organic acids (acetic‐(C‐AA), lactic‐(C‐LA), and propionic (C‐PA)) were evaluated on shelf‐life enhancements of fresh egg quality. All chitosan‐coated eggs showed greater interior quality than the non‐coated eggs. The coatings significantly maintained weight loss compared to the control specimen (4.96%). Lower weight loss (3.45% for C‐PA, 3.53% for C‐LA) was observed in the coated eggs. Eggshell chitosan coat containing lactic and propionic acids maintained higher Haugh unit and yolk index than eggs coated with acetic acid. Uncoated (UC) eggs changed from grade ‘A’ to ‘B’ after 1 week of storage. Chitosan‐based coating containing lactic and propionic acids maintained eggs in grade ‘A’ for 4 weeks. Haugh unit showed that C‐LA and C‐PA effectively maintained eggs at grade ‘A’ quality for at least 3 weeks more than control and 1 week more than C‐AA. Results also indicated that the chitosan coating maintained mineral amounts at nutritional values (especially calcium, iron and magnesium concentration) in yolks after 4 weeks storage. Copyright © 2006 Society of Chemical Industry     

rGO/CuO/PEDOT nanocomposite formation,its characterisation and electrochemical performances for supercapacitors

ABSTRACT

Supercapacitor properties of rGO, CuO, PEDOT and rGO/CuO at [rGO]_o/[CuO]_o?=?1:1; 1:1.5; 1:2 and rGO/CuO/PEDOT nanocomposite at [rGO]_o/[CuO]_o/[EDOT]_o?=?1:1:1; 1:1:3; 1:1:5 were investigated using chemical reduction of GO and in-situ polymerisation process. SEM-EDX, HRTEM, BET surface area analysis confirm the nanocomposite formations. Nanocomposite materials are also analysed through FTIR-ATR, Raman, TGA-DTA, GCD, CV and EIS. The highest specific capacitance of C _sp?=?156.7 F/g at 2?mV/s is determined as rGO/CuO/PEDOT at [rGO]_o/[CuO]_o/[EDOT]_o?=?1:1:5. In addition, two-electrode supercapacitor device for rGO/CuO/PEDOT at [rGO]_o/[CuO]_o/[EDOT]_o?=?1:1:5 are found to provide a maximum specific energy (E?=?14.15 Wh/kg at 20?mA) and specific power (P?=?24730 W/kg at 50?mA), electrical serial resistance (ESR?=?13.33 Ω) with good capacity retention after 3000 cycles. An equivalent circuit model of LR1(CR2)(QR3) is proposed to interpret the EIS data. The supercapacitor performance of the rGO/CuO/PEDOT nanocomposite electrode indicates the synergistic effect of hybrid supercapacitors.