Effect of process parameters on coating composition of cathodic-plasma-electrolysis-treated copper

Cathodic plasma electrolysis is a novel technique to form nanostructured layers on metallic surfaces by application of high voltage in a suitable aqueous electrolyte. In the present study, copper is treated by plasma electrolysis in 50 vol% ethanol electrolyte and coatings comprising carbon nanostructure and copper oxide are formed on the copper. The effect of some process parameters such as electrical conductivity, volume and temperature of electrolyte and ratio of anode to cathode surface area on current–voltage behaviour and subsequently coating compositions are investigated at 150 V deposition voltage. The composition and morphology of these coatings are characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscopy. Different current–voltage behaviours, temperatures of substrate and the contents and energies of radicals and ions around the substrate by changes in the mentioned parameters cause different compositions from 100 vol% copper oxide to different ratios of copper oxide to carbon, the structure changing from amorphous to graphitic structure in carbon and amorphous to cubic morphology in copper oxide on the substrate. Therefore, the understanding of cathodic plasma electrolysis can be developed.     

Proximate Composition, Mineral Content, and Fatty Acids of Catfish (Ictalurus punctatus, Rafinesque) for Different Seasons and Cooking Methods

The effect of conventional cooking methods and the influence of season upon proximate composition, mineral, and fatty acid profile was studied in catfish (Ictalurus punctatus, Rafinesque) fillets. Seasonal (August, December, and April purchased fillets) influences were minimal. As expected, fried catfish fillets had significantly altered (P ≤ 0.05) fatty acid profiles compared to the raw and baked fillets. All three cooking treatments resulted in significant differences (P ≤ 0.05) in proximate composition and in the levels of potassium, phosphorus, magnesium, and iron. The information presented would be useful for nutrient data banks when dietary intake of such items is of interest.     

PREDICTING DRYING BEHAVIOR OF SPAGHETTI IN A CONTINUOUS INDUSTRIAL DRYER WITH THE MODELS DETERMINED IN A LAB SCALE BATCH SYSTEM

In the first stage of this study experimental data were obtained by using a lab scale batch type dryer, operating under various constant temperature/constant relative humidity combinations; then a mathematical model was determined for the effective diffusivity of moisture in spaghetti. In the second stage of the study the model obtained in the lab scale batch type dryer was used to calculate the moisture content of the spaghetti leaving continuous industrial scale dryer, and its success was tested by comparing with the experimentally determined moisture content of the product. The model was not found successful and corrected. Mathematical models based on experimental data obtained in a bench-top laboratory dryer underestimated the apparent equilibrium moisture content and over estimated the effective diffusivity of water in spaghetti in industrial scale continuous drying equipment. The structural differences in the product, extrapolation of the data beyond the range of the original experiments, variations in mode (batch versus continuous), surface-to-volume ratios, flow patterns, and geometry associated with each drying system were anticipated as the cause of the scale up problem.     

WATER ABSORPTION, LEACHING and COLOR CHANGES DURING the SOAKING FOR PRODUCTION of SOY-BULGUR

In this study, the soaking process, which is the first step of soy‐bulgur production to develop a new type food product, was investigated. the soaking operation was conducted at 30, 50 and 70C for 120 min and samples were taken from the soybean and soaking water at 10 min intervals. Moisture content and color (L, a, b and YI values) of soybean were measured, as well as soluble solids content and color (L, a, b and YI values) of soaking water during the soaking process. the results were analyzed by using ANOVA and Duncan test. Soaking time and temperature were significantly effective (P < 0.05) on all variables, except the time effect on the YI‐value. During the soaking, moisture content, lightness (L) and yellowness (b) increased and, redness (a) and yellowness index (YI) of soybean decreased. Soluble solids content, yellowness and yellowness index increased in contrast to a decrease in the lightness and greenness of the soaking water. As a result, soluble solids content in the soaking water increased, which illustrated the leaching of soluble solids from soybean to water. Color of soybean turned to lights, in contrast to darkening and opaqueness of water during soaking. Results showed that the moisture content, soluble solid content, L, a, b and YI values can be successfully modeled using polynomial equations, which can be used to estimate their changes during the soaking operation.     

KINETIC MODELING OF ANAEROBIC THERMAL DEGRADATION OF ASCORBIC ACID IN ROSE HIP (ROSA CANINA L) PULP

Ascorbic acid loss in thermally treated rose hip pulp was modeled mathematically. Isothermal experiments in the temperature range of 70–95C were utilized to determine the kinetics of ascorbic acid loss in the pulp during heating under anaerobic circumstances. Changes in ascorbic acid decomposition followed a first‐order reaction. Temperature dependence of the rate constant during thermal processing of rose hip pulp obeyed the Arrhenius relationship with an activation energy of 47.5 kJ/mole.     

PEKMEZ-DAIRY DESSERTS FORTIFIED WITH SPRAY-DRIED DAIRY POWDERS: EFFECTS OF THE INTERACTION BETWEEN SKIM MILK POWDER, YOGHURT POWDER AND BUTTERMILK POWDER BY A MIXTURE DESIGN APPROACH

A mixture design approach was used to evaluate the interactions between skim milk powder (SMP), yoghurt powder (YP) and buttermilk powder (BMP) on rheological and sensory properties of dairy dessert mixture samples (DDMS). DDMS was prepared with pekmez powder, which was obtained by spray drying of pekmez, also known as concentrated grape molasses. Among the dairy powders, YP was the component that had the most effect on the viscosity of DDMS. The liking of the panelists was more prominent for the dairy dessert samples including the higher concentrations of YP. Optimum values of SMP, YP and BMP in the mixture were found to be 12–46%, 41–90% and 0–39%, respectively with respect to sensory properties.

PRACTICAL APPLICATIONS

The compositional properties of dairy powders can be changed by their usage at particular combinations, which could give rise to an improvement in their rheological and sensory properties. Such modifications would be of great economical importance to food industry. Dairy powders can be used to improve these properties when optimum combination levels of these dairy powders are taken into consideration. Therefore, information obtained in this study may be useful in practical industrial food product process monitoring and development.     

RESPONSE SURFACE METHODOLOGY STUDY ON THE POSSIBILITY OF NITRITE REDUCTION BY GLUCONO-δ-LACTONE AND ASCORBIC ACID IN TURKISH-TYPE FERMENTED SAUSAGE (SUCUK)

The primary goal of this study was to determine the residual nitrite-reducing effects of glucono-δ-lactone (GDL) and ascorbic acid (AA) in Turkish-type fermented sausage. Response surface methodology was used to investigate the simultaneous effects of processing variables, e.g., nitrite (0–200 mg/kg sausage), GDL (0–0.5% w/w) and AA (0–500 mg/kg sausage) on pH, moisture, residual nitrite, proteolysis, lipolysis, peroxide, yield and sensory score of the sausage. AA significantly ( P <  0.01) decreased the residual nitrite level; however, quadratic effect of AA showed an inverse effect. GDL did not produce the same effect on the residual nitrite level. The processing variables had no prominent effect on the proteolysis, lipolysis and peroxide. GDL and AA addition showed a negative effect on the yield and sensory scores of the sausages. The regression model predicted the optimum residual nitrite content to be 0.75 mg/kg. The critical values for nitrite, GDL and AA to obtain this optimum level were 147.56 mg/kg, 0.17% and 565 mg/kg, respectively.

PRACTICAL APPLICATIONS

Residual nitrite level is a major problem in the Turkish-type fermented sausage product with respect to some health concerns, residual nitrite causes a possible formation of the carcinogenic N -nitrosamines. The results of this study can be applied to reduce the residual nitrite level in sausage and to find the optimum levels of nitrite, glucono-δ-lactone and ascorbic acid levels to maintain the characteristic sausage quality properties. Based on the results, ascorbic acid can be used to reduce the residual nitrite levels in the sausage.     

LIQUID–SOLID EXTRACTION OF SOLUBLE SOLIDS AND TOTAL PHENOLIC COMPOUNDS OF CAROB BEAN (Ceratonia siliqua L.)

Total mass transfer coefficients of soluble solids (SS) and total phenolic compounds (TPC) were determined during carob extraction. The Arrhenius equation was applied to determine the efficiency of process temperature, as an alternative approach to Fick's second law. Carob pod, cut into small pieces (internal diameter: 5–7 mm), was contacted with water in batch system to extract SS by continuous circulation of water at different temperatures (20, 50 and 85C). The process was also performed at 85C using an industrial‐scale extractor. Activation energies for both SS and TPC diffusions were calculated as 5.84 and 0.072 × 10^?3 kJ/mol, respectively. As expected, higher extract concentrations were achieved with higher temperatures. In contrast, high extraction temperature, even at 85C, did not cause hydroxymethylfurfural (HMF) formation. As the increase in temperature does not affect formation of HMF during carob pod extraction, higher operational temperatures such as 80–90C may be applied to obtain higher solute concentrations.     

A new anisotropic perfectly matched layer medium for mesh truncation in finite difference time domain analysis

In this paper an unsplit anisotropic perfectly matched layer (PML) medium, previously utilized in the context of finite element analysis, is implemented in the finite difference time domain (FDTD) algorithm. The FDTD anisotropic PML is easy to implement in the existing FDTD codes, and is well suited for truncating inhomogeneous and layered media without special treatment required in the conventional PML approach. A further advantage of the present approach is improved performance at lower frequencies. The applications of the unsplit anisotropic PML/FDTD method are illustrated by considering the problems of a plane wave propagation and an open microstrip line.