Ohmic Heating of Liquid Whole Egg: Rheological Behaviour and Fluid Dynamics

Although ohmic heating is used as an alternative heating method for liquid egg products commercially, there is a lack of information on the change of rheological properties and fluid dynamics characteristics of ohmically heated liquid whole egg in the literature. The change of rheological behaviour of the ohmically heated liquid whole egg, across a temperature range of 4–60 °C, was determined by using a concentric rotational viscometer. The ohmic heating was conducted by applying the voltage gradient (20 V/cm) at 50 Hz. The temperature dependency of the electrical conductivity of liquid egg was linear (R ² = 0.999). The rheological behaviour was found to be shear thinning since power law model had higher regression coefficient and lower χ ² and root mean square error values than Newtonian model. Ohmically heated liquid whole egg exhibited higher degree of thixotropic index indicating the occurrence of the protein denaturation at 60 °C. The flow behaviour of liquid whole egg in the continuous ohmic heating system was predicted as laminar (GRe range of 87.59–538.87) for the mass flow rate range of 0.0056–0.0166 kg/s. The friction factors and pressure losses in the system in those mass flow rates were also assessed. The result of this study will give necessary information on flow characteristics of liquid whole egg for the modelling, designing and the scaling up of the continuous ohmic heating systems for pasteurisation of liquid egg products.     

In vitro cytotoxicity of monticellite based bioactive ceramic powder synthesized from boron derivative waste

The cytotoxicity of monticellite based bioactive ceramic powder, which was synthesized from boron derivative waste has been determined by in vitro assays of MTT, NRU, and JC-1 staining. The toxicity of powder on different mammalian cell lines (3T3-L1, HUVEC, CRL-2120) was evaluated at the concentrations of 10, 100, 200, 400 and 800?µg/mL to justify its potential for biomedical applications. The obtained results showed that monticellite based bioactive ceramic powder possesses not only bioactive feature but also biocompatible characteristic at the concentration range of 10–200?µg/mL. Hence, monticellite based bioactive ceramics have high potential as a bone graft substitute for bone void filling and coating applications.     

Association of physicochemical with technological properties of wheat

This study focused on twenty‐five different European common wheat varieties and aimed to identify correlations between the most important quality characteristics. When considering the physicochemical characteristics of the wheat samples, our results indicated that milling value is not correlated with vitreous kernel and test weight, but is correlated with gliadin/glutenin. The technological properties of the whole‐wheat flours estimated by means of Mixolab indicated rather good protein quality and the ability to form doughs with good stability in case of most of the samples. Technological behaviour of the flour was affected by dietary fibres and pentosan contents. The starch behaviour was positively correlated with the pentosan contents. The principal components analysis allowed establishing correlations between physicochemical, technological and nutritional parameters of wheat varieties. This finding is important for efficient selecting among wheat varieties, especially when healthy cereal‐based foods are desired.     

Equivalent circuit for capacitive micromachined ultrasonic transducers to predict anti-resonances

Equivalent circuit models have been long used to evaluate the dynamics of the capacitive micromachined ultrasonic transducer (CMUT). An important parameter in the characterization of a CMUT is the anti-resonance frequency, which limits the immersion bandwidth. However, there is no equivalent circuit model that can accurately determine the anti-resonance frequency of a membrane. In this work, we present an improved lumped element parametric model for immersed CMUT. We demonstrate that the proposed equivalent circuit model accurately predicts anti-resonance and higher order mode frequencies, in addition to that of the fundamental mode. The proposed circuit model is in good agreement with device characteristics calculated using the finite element method and experimentally measured data.

     

Mechanical properties of bovine hydroxyapatite (BHA) composites doped with SiO<Subscript>2</Subscript>, MgO,Al<Subscript>2</Subscript>O<Subscript>3</Subscript>, and ZrO<Subscript>2</Subscript>

Biologically derived hydroxyapatite from calcinated (at 850 °C) bovine bones (BHA) was doped with 5 wt% and 10 wt% of SiO₂, MgO, Al₂O₃ and ZrO₂ (stabilized with 8% Y₂O₃). The aim was to improve the sintering ability and the mechanical properties (compression strength and hardness) of the resultant BHA-composites. Cylindrical samples were sintered at several temperatures between 1,000 and 1,300 °C for 4 h in air. The experimental results showed that sintering generally occurs at 1,200 °C. The BHA–MgO composites showed the best sintering performance. In the BHA–SiO₂ composites, extended formation of glassy phase occurred at 1,300 °C, resulting in structural degradation of the resultant samples. No sound reinforcement was achieved in the case of doping with Al₂O₃ and zirconia probably due to the big gap between the optimum sintering temperatures of BHA and these two oxides.     

Highly filled polyolefin plastomer formulations for possible PVC replacement in flooring

Calcium carbonate highly filled composites of a polyolefin plastomer (POP), and its blends with postconsumer linear low‐density or high‐density polyethylene (PC‐LLDPE or PC‐HDPE) were prepared and evaluated. The mechanical properties of compounded POP and its blends were compared with those of a PVC–calcium carbonate formulation used for flooring applications. Tensile and impact properties of calcium carbonate‐filled POP composites compare very favorably to the PVC‐based formulation at filler loadings as high as 200 phr. Moreover, postconsumer LLDPE or HDPE can replace at least 50% of the POP in these composites without affecting their main properties. DSC analyses indicate that the synergism occurring in mechanical properties for some of the blend compositions, may be related to the ability of the individual polymers to cocrystallize in the respective blends. This article presents the results of a preliminary study. Continued research is expected to contribute toward a complete characterization of the compounded POP/postconsumer PE blends to establish if they can replace plasticized PVC compounds in some or all flooring applications. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1156–1168, 1999     

Rigid poly(vinyl chloride)-organosolv lignin blends for applications in building

The article presents preliminary work carried out to prepare and evaluate the blends obtained from an unplasticized poly(vinyl chloride) (PVC) compound, formulated with several amounts of TiO₂ and an organosolv lignin. A series of blends in which lignin replaced partially or totally the TiO₂ were made on a laboratory scale. The influence of lignin on the melt processing of the blends and on their stress-strain properties was studied. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were performed to examine the contribution of lignin to the properties of these blends. The possibility of a proton donor/proton acceptor interaction between lignin and PVC chains is discussed. This can arise due to the interaction between the carbonyl group of lignin and α hydrogen of PVC or between hydroxyl groups of lignin and chlorine of PVC. © 1996 John Wiley & Sons, Inc.     

Utilization of natural antioxidants: Green tea extract and Thymbra spicata oil in Turkish dry-fermented sausage

Effect of natural (green tea extract, Thymbra spicata oil) and synthetic antioxidants (buthylatedhydroxytoluene, BHT) on the safety (biogenic amine and TBARS values) and quality (pH, colour and sensory attributes) of sucuk (Turkish dry-fermented sausage) were investigated during the ripening periods. Addition of antioxidants decreased (P<0.05) the TBARS values. It was found that natural antioxidants decreased TBARS formation more than BHT. Antioxidants reduced (P<0.05) putrescine formation in the following order: green tea extract>green tea extract-T. spicata oil>T. spicata oil>BHT, and their mean values were 70.45, 76.05, 83.13, and 95.97mg/kg, respectively. The highest tyramine concentration was observed in control sucuk prepared without any antioxidants, while the lowest was in the recipe with green tea extract as their mean values were about 99.42 and 64.31mg/kg, respectively. The pH, L, b, and overall sensory quality were not significantly different (P>0.05) with the addition of green tea extract, T. spicata oil, green tea extract-T. spicata oil. These results indicated that the most effective antioxidant was found to be green tea extract. This study pointed out that natural antioxidants were more effective than synthetic antioxidants, so they could be easily utilized in sucuk to enhance quality and provide safer products.     

Characterization of water-soluble conjugates of polyacrylic acid and antigenic peptide of FMDV by size exclusion chromatography with quadruple detection

Intermolecular complex by electrostatic interaction and specifically coupled conjugates between polyacrylic acid (PAA) and a synthetic peptide representing 170-188 sequence from the GH loop of VP1 protein of foot-and-mouth disease virus (FMDV) were investigated as an intermolecular model system due to their importance in biotechnology and immunology. In this study, polyacrylic acid (PAA) with a synthetic peptide representing 170-188 sequence from the GH loop of VP1 protein of foot-and-mouth disease virus at a wide range of mixing ratios of components (C_Peptide/C_PAA 0.1, 0.25, 0.5, 0.75 and 1.0, respectively) were characterized by size-exclusion high performance liquid chromatography with on-line refractive index, UV, light scattering and viscometer detectors. The results revealed that two molecules are both negatively charged as a result of repulsive forces preventing complex formation at neutral pH. Therefore, these molecules bound covalently to each other by using water-soluble carbodiimide when pH levels are higher than the pI of the peptide. High performance liquid chromatography analysis showed that the amount of protein-polymer complex increased and free peptide amount decreased with the increase in molar ratio of the peptide. Also, this paper presents that number of the bound peptide molecules with one PAA molecule was expressed by a Langmuir-type equation as a function of the amount of excess synthetic peptide existing free in the solution.