The effects of modified atmosphere gas composition on microbiological criteria, color and oxidation values of minced beef meat

This paper reports the effects of modified atmosphere gas compositions with different concentrations of CO(2)/O(2)/N(2) on color properties (L*, a* and b* values), oxidation stability (TBARS value) and microbiological properties of minced beef meat stored at +4 °C. Sampling was carried out on the 1st, 3rd, 5th, 7th, 9th, 11th and 14th day of storage. The gas mixtures used were as follows: (i) %30O(2) + %70CO(2) (MAP1), (ii) %50O(2) + %50CO(2) (MAP2), (iii) %70O(2) + %30CO(2) (MAP3), (iv) %50O(2) + %30CO(2) + %20N(2) (MAP4), and (v) %30O(2) + %30CO(2) + %40N(2) (MAP5). Control samples (AP) were packaged under atmospheric air. Pseudomonas, lactic acid bacteria, Brochothrix thermosphacta, and Enterobacteriaceae members were monitored. Among these five modified atmosphere gas compositions, the best preservation for minced beef meat was in MAP4 gas combination maintaining acceptable color together with oxidation stability and acceptable microbial loads until the end of storage period of fourteen days.     

Solid solution limit of Fe2O3 in mullite crystals,produced from kaolin by solid state reactions

Porcelain, wall/floor tiles, and roofing tiles are classified as traditional ceramics and are produced from natural raw materials such as clay, quartz, and feldspar. The raw materials are selected by the oxide content which provides the desired properties of the final product. However, impurities such as Fe₂O₃ and TiO₂ may have a significant influence on both physical/mechanical properties and aesthetic appearance. Fe₂O₃, which is of particular importance, causes black maculation formation in tablewares, in which whiteness is essential. The only way to overcome the black maculation is to corrupt the Fe₂O₃ crystal structure and to employ Fe^2+/3+ cation, making a solid solution with a host crystal (i.e. mullite-3Al₂O₃·2SiO₂). The aim of this study is to identify the solubility limit of Fe₂O₃ in mullite crystals. With the scope of the study, an illite/kaolinite was utilized by adding an increasing amount of Fe₂O₃ (e.g. 1–2–4–6–8–10?wt%) into the recipes fired at 1300?°C for 3?h after homogenization. According to the mullite phase content, it is concluded that ~ 5?wt% of Fe₂O₃ could be dissolved in mullite crystal structure on the basis of the Rietveld refinement of the XRD patterns.     

Determination of Membrane Protein Fouling by UV Spectroscopy and Electrochemical Impedance Spectroscopy

UV spectroscopy and electrochemical impedance spectroscopy were used to investigate the properties and performances of ultrafiltration membranes fabricated with different polymers. Membrane performances were studied by means of permeability and bovine serum albumin filtration. UV spectroscopy results showed that bovine serum albumin rejection was lowest in polyvinylidene fluoride membranes, whereas it was highest in polysulfone membranes. Electrochemical impedance spectroscopy data revealed that after bovine serum albumin filtration, resistance of the membranes was increased though double layer capacitances were decreased. Performance data of UV spectroscopy and electrochemical impedance spectroscopy were in correlation with each other. This study demonstrated that electrochemical impedance spectroscopy can be successfully used in filtration membrane studies.     

The use of Bacillus subtilis immobilized on Amberlite XAD-4 as a new biosorbent in trace metal determination

The present work proposes the use of Bacillus subtilis immobilized on Amberlite XAD-4 as new biosorbent in trace metal determination. The procedure is based on the biosorption of Cu and Cd ions on a column of Amberlite XAD-4 resin loaded with dried, dead bacterial components prior to their determination by flame AAS. Various parameters such as pH, amount of adsorbent, eluent type and volume, flow rate of solution and matrix interference effect on the retention of the metal ions have been studied. The optimum pH values of quantitative sorption for Cu and Cd were found to be 7.0 and 7.5, respectively. These metal ions can be desorbed with 1M HCl (recovery, 96-100%). The sorption capacity of the resin was 0.0297 and 0.035 mmol g(-1) for Cu(2+) and Cd(2+), respectively. The tolerance limit of some electrolytes were also studied. This procedure was applied to Cu(2+) and Cd(2+) determination in aqueous solutions, including river and well water systems. In order to evaluate the accuracy of the proposed procedure, the certified reference materials, NRCC-SLRS-4 Riverine water and LGC7162 Strawberry leaves were analyzed.     

New monomers and polymers derived from α‐hydroxymethyl methyl vinyl ketone

2‐Hydroxymethyl‐but‐1‐ene‐3‐one [α‐hydroxymethyl methyl vinyl ketone (HMVK)] was synthesized from methyl vinyl ketone using paraformaldehyde and a tertiary amine catalyst. Free‐radical polymerization of this monomer created transparent, tough polymers that were insoluble in organic solvents. HMVK was converted to trimethylsilyl, acetate, and chloride derivatives. When the hydroxyl group was thus protected or removed, all these monomers could be free radically polymerized in bulk to make soluble polymers. The chlorination reaction is complicated by the formation of 1,1‐bischloromethylacetone, which dehydrohalogenated unexpectedly to the desired α‐chloromethyl methyl vinyl ketone. HMVK will self‐condense to an ether dimer in the presence of a catalytic acid. This reagent is capable of crosslinking many alkene monomers through hydrolytically stable ether bonds. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 509–516, 2000     

Synthesis,structure, and thermo‐physical properties of Fe2O3.Al2O3 and polyethylene nanocomposites

In this study, Fe₂O₃.Al₂O₃/polyethylene composites were prepared using a two‐step process. In the first step, PE is synthesized using titanium based metallocene catalyst system. While the synthesized PE was subsequently purified, hydrated alumina filled PE (MHFP) composites was formed by the hydrolysis of methylaluminoxane (MAO). In the second step, Fe₂O₃.Al₂O₃/PE was prepared via thermal decomposition of ferric formate in a high temperature solution of MHFP composite. The structure, morphology, and thermal properties of the composites were characterized using the XRD, FTIR, SEM‐EDX, TGA, and DSC analytical techniques. Results showed that the incorporation of a suitable amount of Fe₂O₃.Al₂O₃ into the composites enhances the thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and study of thermal properties of phase change materials based on paraffin–alumina‐filled polyethylene

Novel phase change materials based on paraffin and alumina‐filled polyethylene (FPE) were prepared using a two‐step process. In the first step, PE is synthesized using metallocene catalyst system. The synthesized PE is subsequently purified, whereas hydrated alumina–PE composites will be formed by the hydrolysis of aluminum organic cocatalyst and dispersion of hydrated alumina in the PE matrix. In the second step, paraffin–alumina‐FPE composites were prepared by using the ex situ technique. Scanning electron microscopy, X‐ray diffraction, Fourier‐transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry were used to evaluate the structure and thermal properties of the composites. The results show that the incorporation of a suitable amount of alumina into the composites changes their thermal stability. It is also possible to improve the thermophysical properties of the thermal energy storage materials by altering the paraffin ratio to the FPE. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Control of Some Filamentous Fungi and Yeasts by Dehydrated Allium Extracts

The antifungal activities of dehydrated garlic (Allium sativum L.), onion (Allium cepa L.) and leek (Allium porrum L.) against Aspergillus niger, Fusarium oxysporum, Candida albicans ATCC 10231 and Metschnikowia fructicola were investigated. Inhibition activities of the ethyl alcohol or acetone extracts of dehydrated Allium species were studied by disc-diffusion and broth dilution methods. The Minimum Inhibitory Concentration (MIC) and the Minimum Fungicidal Concentration (MFC) were found in the range of 75 and 100 mg/mL (w/v). Ethyl alcohol extracts of dehydrated onion (Allium cepa L.) in the range of 75 and 175 mg/mL were determined as the most inhibitory MIC and MFC for A. niger, F. oxysporum and C. albicans respectively. The extracts possess antifungal activity against some of the tested filamentous fungi and yeasts at various concentrations.