Effects of microwave frying and different flour types addition on the microstructure of batter coatings

In this study, the influences of microwave frying and various flour types on microstructure of batter coatings were investigated. Control batter formulation contained only wheat and corn flour. To determine the effects of different flour types, 30% of the corn and wheat flour mix was replaced with chickpea, rice or soy flours. Frying was performed in microwave oven at 365 W (70%) power level for 1.5 min after bringing the oil temperature to 180 ± 1 °C. Samples were also fried in a conventional fryer at 180 °C for 1.5 and 5.0 min for comparison. Microwave fried samples had higher specific bulk volume and porosity values and also smoother inner surface as compared to conventionally fried samples. Porosity values of different batter formulations were in the range of 0.425–0.484 in 1.5 min microwave fried chicken samples and 0.348–0.392 in 5.0 min conventionally fried ones. Microwave fried samples had comparable or lower hardness values than the conventionally fried ones depending on the flour type used in batter formulation. Microstructure of fried batter was different for different batter formulations. Microwave fried control and chickpea flour containing batter provided formation of larger gas cells on the outer surface. Soy flour containing batter resulted in smallest size gas cells for both frying methods.     

Hydrophobic microbeads as an alternative pseudo-affinity adsorbent for recombinant human interferon-α via hydrophobic interactions

Hydrophobic interaction chromatography (HIC) is increasingly used for protein purification, separation and other biochemical applications. The aim of this study was to prepare hydrophobic microbeads and to investigate their recombinant human interferon-α (rHuIFN-α) adsorption capability. For this purpose, we had synthesized functional monomer, N-methacryloyl-l-phenylalanine (MAPA), to provide a hydrophobic functionality to the adsorbent. The poly(2-hydroxyethyl methacrylate-N-methacryloyl-l-phenylalanine) [poly(HEMA–MAPA)] microbeads were prepared by suspension copolymerization. microbeads were characterized using FTIR, swelling behavior, and SEM micrographs. Equilibrium swelling ratio of poly(HEMA–MAPA) and poly(HEMA) microbeads were 53.3% and 69.3%, respectively. The specific surface area and average pore diameters determined by BET apparatus were 17.4 m²/g and 47.3 Å for poly(HEMA) microbeads and 18.7 m²/g and 49.8 Å for poly(HEMA–MAPA) microbeads. Adsorption experiments were performed under different conditions. Maximum rHuIFN-α adsorption capacity was found to be 137.6 ± 6.7 mg/g by using poly(HEMA–MAPA) microbeads with a size range of 150–250 μm and containing 327 μmol MAPA/g microbeads. Compared with poly(HEMA–MAPA) microbeads, nonspecific rHuIFN-α adsorption onto plain poly(HEMA) microbeads was very low, about 4.2 ± 2.3 mg/g. To determine the effects of adsorption conditions on possible conformational changes of rHuIFN-α structure, fluorescence spectrophotometry was employed. Repeated adsorption–elution processes showed that these microbeads are suitable for repeatable rHuIFN-α adsorption.     

Multi-unit controlled release systems of nifedipine and nifedipine:pluronic F-68 solid dispersions: characterization of release mechanisms

Nifedipine (N) and nifedipine:Pluronic® F-68 solid dispersion (SD) pellets were developed and characterized for drug release mechanisms from a multi-unit erosion matrix system for controlled release. Nifedipine was micronized using a jet mill. Solid dispersion with Pluronic F-68 was prepared by the fusion method. Nifedipine and SD were characterized by particle size analysis, solubility, differential scanning calorimetry (DSC), and x-ray diffraction (XRD) studies. Samples were subsequently processed into matrix pellets by extrusion/spheronization using Eudragit® L 100-55 and Eudragit® S 100 as release rate-controlling polymers. Drug release mechanisms from pellets were characterized by microscopy and mercury intrusion porosimetry; DSC and XRD studies indicated no polymorphic changes in N after micronization and also confirmed the formation of SD of N with Pluronic F-68. Pellets of N showed a 24-hr drug release profile following zero-order kinetics. Pellets of SD showed a 12-hr release profile following first-order kinetics. Aqueous solubility of N after SD formation was found to be increased 10-fold. Due to increased solubility of N in SD, the drug release mechanism from the multi-unit erosion matrix changed from pure surface erosion to an erosion/diffusion mechanism, thereby altering the release rate and kinetics.     

Isolation of volatile oil from thyme (Thymbra spicata) by steam distillation

The effects of steam flow rate (1.03 and 0.64 L/h), distillation time, and particle size (0.50, 1.00, 2.05 mm) of Thymbra spicata on essential oil yield and sequence of extraction of compounds were studied. A logarithmic model fitted well to experimental data. The composition of the essential oil obtained by steam distillation was investigated for whole leaves only since the grinding had an adverse effect on yield. The oil obtained was very rich with respect to its carvacrol content. For both steam flow rates, oxygenated monoterpenes were recovered the most rapidly. Using whole leaves (2.05 mm) and a higher steam flow rate (1.03 L/h) for 75 min of distillation was chosen as the optimum which gives the lowest amount of monoterpene hydrocarbons, the complete recovery of oxygenated compounds, and the highest yield in a shorter time. Yield was 1.57% at this optimum condition. The oil was composed of 53.1% oxygenated compounds, 25.7% monoterpene hydrocarbons, 4.4% sesquiterpenes, and 14.1% p-cymene.     

Effects of different emulsifier types,fat contents,and gum types on retardation of staling of microwave-baked cakes

The effects of different types of emulsifiers, gums, and fat contents on the retardation of staling of microwave-baked cakes were investigated. First, different types of emulsifiers (DATEM, Lecigran, and Purawave) at three different fat contents (50%, 25%, and 0%) were added to cake formulations to retard staling of microwave-baked cakes. Then, three types of gums (guar gum, xanthan gum, and methylcellulose) were added to the optimum formulations chosen. As a control, cakes formulated without any emulsifier or gum addition and baked in an conventional oven at 175 degrees C for 25 min was used. Weight loss, firmness, soluble starch and amylose content of the cakes were used as the indicators of staling criteria. Cakes were baked in a microwave oven for 1.5 min at 100% power. Variation of staling parameters during storage of cakes followed zero-order kinetics. Use of emulsifiers and gums helped to retard staling of microwave-baked cakes. Fat content was found to be a significant factor in affecting variation of firmness and weight loss of the cakes during storage. DATEM and Purawave were the most effective emulsifier types. Using gums in combination with emulsifiers gave better moisture retention and softer cakes than using gums alone.     

Novel Type of Metal-Containing Polyimides for the Heck and Suzuki–Miyaura Cross-Coupling Reactions as Highly Active Catalysts

Novel palladium (II)-containing polyimides with exceptional catalytic properties for the Heck and Suzuki–Miyaura cross-coupling reactions were prepared from Pd(II)--bis(imine) complex and the corresponding dianhyrides. The glass transition temperatures (T _g ) of the polymers ranged from 169 to 241°C. The temperatures at which 10% weight loss occurred in air ranged from 415 to 579°C. Polyimides based on the palladium (II) complex were tested for catalytic activity in the Heck coupling reaction between styrene and several aryl halides and the Suzuki coupling reaction between phenylboronic acid and several aryl halides. The negative effects (e.g., expense, low reaction rates, air-sensitivity) experienced by using phosphines, particularly electron-rich phosphines, as catalysts in large scale applications is overcome by using polymer supported catalysis.     

Retrofit of a Three-Span Slab Bridge with Fiber Reinforced Polymer Systems—Testing and Rating

A 45-year old, three-span reinforced concrete slab bridge with insufficient capacity was retrofitted with 76.2- and 127-mm wide bonded carbon fiber-reinforced polymer (FRP) plates, 102-mm wide bonded carbon FRP plates with mechanical anchors at the ends, and bonded carbon FRP fabrics. The use of four systems in one bridge provided a unique opportunity to evaluate field installation issues and to examine the long-term performance of each system under identical traffic and environmental conditions. Using controlled truckload tests, the response of the bridge before retrofitting, shortly after retrofitting, and after one year of service was measured. The stiffness of the FRP systems was small in comparison to the stiffness of the bridge deck, and accordingly the measured deflections did not change noticeably after retrofitting. The measured strains suggest participation of the FRP systems, and more importantly, the strength of the retrofitted bridge was increased. A detailed 3D finite-element model of the original and retrofitted bridge was developed and calibrated based on the measured deflections. The model was used to predict more accurately the demands for computing the rating factors. The addition of FRP plates and fabrics led to a 22% increase in the rating factor and corresponding load limits. During a one-year period, traffic loading and environmental exposure did not apparently affect the performance of the FRP systems. The increased capacity and acceptable performance of the FRP systems enabled the engineers to remove the load limits in order to resume normal traffic. Future tests are necessary to monitor the long-term behavior of the FRP systems.     

Pseudospecific magnetic affinity beads for immunoglobulin‐G depletion from human serum

Magnetic poly(ethylene glycol dimethacrylate‐N‐methacryloyl‐(L )‐histidine methyl ester) [m‐poly(EGDMA‐MAH)] beads were prepared by suspension polymerization for the affinity depletion of immunoglobulin‐G (IgG) from human serum in a batch system. Elemental analysis of the magnetic beads for nitrogen was estimated as 70 μmol MAH/g polymer. IgG adsorption onto the m‐poly(EGDMA) was negligible. Higher adsorption value (up to 46.8 mg/g) was obtained in which the m‐poly(EGDMA‐MAH) beads were used. IgG adsorption capacity of the magnetic beads increased with an increase in the concentration of IgG. The maximum IgG adsorption was observed at pH 6.5 for MOPS buffer. IgG molecules could be repeatedly adsorbed and eluted with these adsorbents, without noticeable loss in their IgG adsorption capacity. Adsorption capacity decreased for both increasing salt concentration and temperature. In this study, we show that m‐poly(EGDMA‐MAH) beads (wherein IgG molecules bind directly with the matrix) can be used directly for affinity depletion without further modification. Higher adsorption value was obtained from human serum (up to 85.7 mg/g). The elution results demonstrated that the adsorption of IgG to the adsorbent was reversible. The depletion efficiencies for IgG were above 85% for all studied concentrations. Eluted portion was analyzed for testing the IgG removal efficiency by two dimensional gel electrophoresis. Eluted proteins include mainly IgG, and a small number of nonalbumin proteins such as apolipoprotein A1, serotransferrin, haptoglobulin, and α1‐antitrypsin. IgA was not identified in eluted fraction. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

A Study on Degree of Starch Gelatinization in Cakes Baked in Three Different Ovens

The main objective of the study was to determine the effects of different baking ovens and different cake formulations on the degree of starch gelatinization during cake baking. Baking was performed in microwave, infrared–microwave combination, and conventional ovens. Starch gelatinization levels of fat free, 25% fat, and 25% Simplesse™-containing cake samples were examined using differential scanning calorimeter (DSC) and rapid visco analyzer (RVA). Both DSC and RVA results showed that increasing baking time increased gelatinization level for all baking types significantly. It was also found that the effect of fat content on starch gelatinization was different depending on the type of baking. Addition of fat reduced the degree of starch gelatinization in conventional baking. However, fat enhanced the gelatinization in microwave and infrared–microwave combination ovens. Usage of Simplesse™ as a fat replacer decreased the starch gelatinization in all types of baking significantly. There was insufficient starch gelatinization in microwave-baked cakes in which the degree of gelatinization ranged from 55% to 78% depending on formulation. On the other hand, it ranged from 85% to 93% in conventionally baked cakes. Combining infrared with microwaves increased degree of starch gelatinization (70–90%).     

Predicting the cookie quality of flours by using Mixolab<Superscript>®</Superscript>

The objective of this study was to determine the possibility of using Mixolab^® to predict the cookie baking quality of different wheat flours. Mixolab data was also compared with various flour quality characteristics. There were significant correlations (P < 0.001) between Mixolab stability and some of the flour quality characteristics (protein and wet gluten contents, Zeleny sedimentation value). Alveoconsistograph T value was negatively correlated with Mixolab C3, C4 and C5 values. The cookie diameter gave highly significant correlations with protein content, Zeleny sedimentation value and damaged starch content. Mixolab C3 and C4 values were highly correlated (P < 0.001) with both cookie diameter and spread ratio. A significant correlation coefficient (r = 0.556) was determined between the cookie diameter and C1–C2 value which is an indication of protein quality. The dependence of cookie diameter and spread ratio on Mixolab C3 value, damaged starch content and Zeleny sedimentation value were analyzed with multiple regression analysis and high multiple correlation coefficients were found between these parameters (r = 0.948 and 0.861, respectively).