Anti-Listeria monocytogenes effect of bacteriocin-incorporated agar edible coatings applied on cheese

Bacteriocins synthesised by lactic acid bacteria are natural alternatives to control Listeria monocytogenes, a foodborne pathogen. Additionally, antimicrobial biopolymer coatings have significant benefits in food packaging and preservation. The effect of anti-L. monocytogenes enterocins synthesised by Enterococcus avium DSMZ17511 was evaluated when supported on agar edible films and applied as antimicrobial coatings on different cheese matrices artificially contaminated with L. monocytogenes 01/155. A decrease of at least 1 log unit in viability of the pathogen was detected. The wetter matrix of soft cheese facilitated rapid diffusion of the antimicrobials, while the drier matrix of semi hard cheese produced a gradual release with prolonged inhibition of the pathogen. Also, DSMZ17511 antimicrobial peptides, only at very high concentrations, exhibited mild cytotoxicity against L929 and Caco-2 cell lines. Therefore, application of these enterocin agar coatings could be an effective, low cost, natural and safe alternative to control L. monocytogenes in cheeses.     

Evaluation on some finishing properties of oil palm plywood

Oil palm is the largest and most important plantation crop in Malaysia. The oil palm generally lasts for 25–30 years before the next replantation is done. Substantial amount of biomass in the form of palm trunk results from plantation cycle. This resource is simply left on the ground to decay and is not used as raw material to manufacture any kind of value-added products. The objective of this study was to investigate the possibility of manufacturing plywood from oil palm trunks and to evaluate some of the finishing properties of such experimental panels in comparison to those from Shorea sp as control samples. Three-ply plywood samples were produced from 5 mm thick veneers of oil palm using urea formaldehyde adhesive. Three types of chemicals, namely nitrocellulose, pre-catalyzed lacquer and polyurethane were used to finish experimental panels. The surface finished with nitrocellulose had the lowest contact angle on raw surface of oil palm plywood and wood. The average cross cut tape index of oil palm plywood was comparable to Shorea sp. All finishing materials of oil palm plywood produced impact rating of 4 except for surface finished with nitrocellulose while finishing on wood indicated an impact rating of 3. Oil palm plywood had higher weight loss compared to Shorea sp. Based on results from contact angle, cross cut tape index, impact rate test, weathering, and soil burial test methods it appears that the samples showed acceptable finishing properties comparable to those of solid wood.     

Fire performance and decay resistance of solid wood and plywood treated with quaternary ammonia compounds and common fire retardants

In this study, the fire performance and decay resistance of solid wood and plywood treated with quaternary ammonia compounds (didecyl dimethyl ammonium chloride (DDAC) and didecyl dimethyl ammonium tetrafluoroborate (DBF)) were compared with the performance of untreated control specimens and specimens treated with common fire retardants ((monoammonium phosphate (MAP), diammonium phosphate (DAP) and ammonium sulphate (AS)). Test specimens were treated with 1% and 4% (% m/v) aqueous solutions of the chemicals. The fire performance tests were the fire tube test (ASTM E 69) which measures mass losses in the specimens and the cone calorimeter test (ASTM E 1354) which measures mass loss, heat release rate, time for sustained ignition, effective heat of combustion, and specific extinction area. The results from the cone calorimeter tests were used to estimate the flame spread index (FSI) in the Steiner tunnel test (ASTM E 84). Heat release rates of the specimens treated with MAP, DAP, and AS were lower than those of both DDAC and DBF-treated specimens and the untreated control specimens. Compared with the untreated specimens, higher heat release rates were observed for the specimens treated with the quaternary ammonia compounds, DDAC and DBF. The estimates for the FSI for DDAC and DBF were for values equal to or higher than for the untreated control specimens. At higher concentration levels, MAP, DAP and AS were effective in decreasing initial contribution of heat release to potential fire. Decay resistance tests were done according to AWPA E 10 standard method using one brown-rot fungus and one white rot-fungus. Decay resistance tests revealed that solid wood specimens treated with DDAC and DBF showed resistance against the fungi tested, however, MAP, DAP and AS did not provide complete protection. While DBF and DDAC increased resistance of plywood specimens, high mass losses in plywood specimens treated with MAP, DAP and AS were obtained.     

Layer-by-layer self-assembly of reduced graphene oxide on bamboo timber surface with improved decay resistance

Because bamboo is easily attacked by many fungi, and conventional preservatives have many disadvantages including environmental pollution and human health damage, bamboo products should be protected with environmentally friendly methods. Herein, a novel and efficient process for fabrication of antifungal bamboo timber by coating with graphene materials is presented. The crystal phase, morphology, microstructure and other physicochemical properties of the as-prepared samples were characterized by XRD, Raman, SEM, EDX, XPS and FTIR. XRD studies and Raman spectrum confirmed that graphene oxide was reduced to graphene aggregates in the one-step hydrothermal reduction process. SEM images proved that reduced graphene oxide (RGO) nanoplates were deposited on bamboo timber surface by layer-by-layer self-assembly. EDX proved the carbon element composition of RGO coating on the bamboo surface. XPS and FTIR indicated strong interaction of hydrogen bond between bamboo substrate and RGO coating. The anti-fungal activity of bamboo timber with RGO coating was improved significantly when bamboo was infected by Gloeophyllum trabeum and Panerochaete chrysosporium.     

Study on the water resistance of plywood bonded with UF-glutaraldehyde adhesive

A UF-glutaraldehyde adhesive system was used for the preparation of three-ply plywood. It was shown that 10 wt % content of the modifier markedly improves the durability of the plywood in water. The obtained wet shear strengths are comparable to those of dry plywood.     

Study on the water resistance of plywood bonded with UF-glutaraldehyde adhesive

A UF-glutaraldehyde adhesive system was used for the preparation of three-ply plywood. It was shown that 10 wt % content of the modifier markedly improves the durability of the plywood in water. The obtained wet shear strengths are comparable to those of dry plywood.     

羊毛混纺耐高温阻燃织物的研究与开发

通过对国内阻燃纺织品应用前景的介绍,比较了羊毛混纺阻燃织物的加工方法,指出羊毛与阻燃纤维混纺织成的耐高温阻燃织物具有工艺简单,成本低,阻燃性能好,舒适性好,耐久性强的特点,详细介绍了羊毛与耐高温阻燃纤维,阻燃改性纤维的混纺产品及应用。     

Viability of some probiotic coatings in bread and its effect on the crust mechanical properties

The objective of this study was to obtain functional bread combining the microencapsulation of Lactobacillus acidophilus and starch based coatings. Different probiotic coatings (dispersed or multilayer) were applied onto the surface of partially baked breads. In all treatments, microencapsulated L. acidophilus survived after baking and storage time, although reduction was higher in the sandwich treatment (starch solution/sprayed microcapsules/starch solution). Despite coatings significantly affected the physicochemical properties of the crust, increasing water activity and reducing the failure force, the sensory evaluation revealed a good acceptability of the functional breads. Scanning electron microscopy revealed the presence of scattered microcapsules onto the bread crust, being highly covered in the sandwich coating. Therefore, L. acidophilus included in microcapsules can be incorporated to bread surface through edible coatings, leading functional bread with similar characteristics to common bread, but with additional healthy benefits.     

涂料流变学性能——实用化的流变学

文章对涂料流变性能的基本类型、涂料流变性能的基本要求、涂料组分的流变性能作了论述,通过现有仪器的流变性能的测定,预测或模拟实际涂布的运行情况,完善涂料的流变性能,改进涂布运转性.     

Improved water resistance of UF adhesives for plywood by small pMDI additions

Addition of small amounts of isocyanate (pMDI), between 10% and 15% by weight, to UF resins for plywood considerably improve the UF glue line water resistance. Analysis of the plywood by X-ray microdensitometry indicate that on both sides of the glue lines there is a local density increase which reflects either some adhesive diffusion in the wood layers immediately in contact with the glue line, or some extent of wood densification as a result of the gluing process, or both.     

Discolouration of white coatings applied on kiln- and air-dried scots pine lumber

During drying, the low-molecular weight (LMW) sugars and nitrogenous compounds are redistributed and accumulated at the lumber surface. These soluble substances may migrate into coatings and cause discolouration. The aim of the present study was to determine the susceptibility to discolouration of white coatings, applied on kiln- and air-dried lumber surfaces with different content of LMW sugars and nitrogen. The differences in the discolouration were more distinct between the coatings than between the drying treatments. Planing had no significant effect on the discolouration, which proved that the different content of soluble substances at the original and planed surfaces did not induce significantly different discolouration. The type of drying and the actual contents of soluble substances at the surface, played a minor role in the discolouration process. The discolouration of all five coatings can be characterized as “fading”, due to decreased colour saturation and lightness.     

The effect of pig slurry applied to a soil surface on the composition of the soil atmosphere

Intensive livestock production and labour-saving methods of husbandry require the storage and subsequent disposal of large volumes of slurry on land. The effect of pig slurry, applied to a soil surface, on the composition of the soil atmosphere was investigated using laboratory soil columns. When the effect of slurry was compared with equivalent amounts of glucose, results showed that while both energy sources increased microbial activity, slurry also sealed soil pores, slowing gaseous diffusion rates and delaying the return of the composition of the soil atmosphere to that approaching air. Repeated slurry applications completely sealed the soil surface and oxygen in the soil atmosphere was rapidly depleted. Ethylene, capable of harmfully affecting root-growth, was produced in the anaerobic soil. The fine solids fraction (less than 250 μm particle diameter) of slurry was most effective at blocking soil pores to gaseous diffusion.     

Effect of edible surface coatings followed by dehydration on some quality attributes and antioxidants content of raw and blanched tomato slices

Changes in quality attributes and antioxidants content of tomato slices coated with gum Arabic at different concentrations then sun- or air-dried were investigated. Drying increased the dry matter content and the rehydration ratio with increase in gum Arabic concentrations. The water activity was fluctuated. Slices coated with 10% gum Arabic and air-dried had a maximum dry matter content (84.87%), a minimum water activity value (0.27) and a higher rehydration ratio (4.69), compared to uncoated slices. Drying of slices before and after coating had no significant (p≤0.05) effect on the pH. Coating of the slices followed by drying had no effect on the total soluble solids content. Blanched slices coated with 10% gum Arabic and sun-dried had a lower browning index value (0.029). Dried uncoated slices were darker than coated slices. Surface coating alleviates the effect of heat on the ascorbic acid, total phenolics, and flavonoid contents.     

Comparative decay resistance of 43 mexican tropical hardwoods

Decay resistance (natural durability) of 43 Mexican tropical hardwoods were tested according to ANSI/ASTM D 2071-71.     

Antimicrobial activity of the surface coatings on TiAlZr implant biomaterial

This study is devoted to antimicrobial activity of new surface coatings on TiAlZr. Ti alloys such as TiAlZr are used as implant biomaterials, but, despite the good behavior of such alloys in simulated conditions, bacterial infections appear after the introduction of an implant into the body. The infections are typically caused by the adherence and colonization of bacteria on the surfaces of the implants. The study presents preparation and surface morphology characterization of coatings obtained via anodizing, as well as biomimetic coatings with hydroxyapatite and silver ions with and without antibiotic. The percentage inhibition of Escherichia coli bacteria growth was evaluated for each of the studied coating, and a Trojan-horse model of silver nanoparticles (nAg) antibacterial activity at interface was proposed. Such coatings could be more important taking into account that antibacterial treatments with antibiotics are becoming less effective due to their intensive use.     

Effect of photocatalytic and hydrophobic coatings on brewery surface microorganisms

The aim of this study was to determine whether process hygiene in the beverage industry could be improved by applying new coating techniques to process surfaces. Photocatalytic titanium dioxide (TiO(2)) and hydrophobic coatings applied to stainless steel with or without added antimicrobial compounds were studied in laboratory attachment tests and in a 15-month process study. No clear reductions in numbers of attached microbes were obtained with photocatalytic coatings, except for coatings to which silver had been added. These TiO(2)+Ag coatings reduced microbial coverage in laboratory studies and in some process samples. Hydrophobic coatings reduced the area coverage of microorganisms in 4-h laboratory studies but did not affect colony counts in laboratory or process studies. The surfaces had changed from hydrophobic into hydrophilic during the process study. The coatings did not mechanically fully withstand process conditions; part of the hydrophobic coatings had peeled off, most of the precipitated Ag had dissolved, and some of the TiO(2) coatings were damaged. In conclusion, functional coatings have potential for reducing microbial loads on beverage industry surfaces, but these coatings need further development.     

Impact of the intumescent formulation of styrene acrylic-based coatings on the fire performance of thin painted red lauan (Parashorea spp.) plywood

Intumescent material with commercial resin, such as styrene acrylic copolymer resin, has been demonstrated to be extremely effective in improving the fire performance of wooden materials used for indoor furnishing. The formulation of the coating is a key to its ability to improve flame retardance. This study investigates the enhancement for painted thin red lauan (Parashorea spp.) plywood. The ability of the material to retard flame arises due to the interactions between the four major components of intumescent formulation: (1) a binder resin (BR), styrene acrylic emulsion resin, (2) a carbonizing substance (CS), pentaerythritol (3) a foam producing substance (FPS), melamine and (4) a dehydrating agent (DA), ammonium polyphosphate. This paper compares the fire performance of the plywood when coated with resin of differing BR/CS ratios (designated as the FRS series) and FPS/DA ratios (designated as the FRD series), by means of a cone calorimeter. These intumescent formulations significantly enhanced the fire retardancy of painted plywood, exhibiting lower peak heat release rates, higher expansion of the intumescent layer and longer time to peak heat release rates (PHRR), when compared to plywood panels coated with sole binder resin. However, worse performance was presented when compared with the data for uncoated plywood panels if the intumescent was produced by equal ratio of the four components. Therefore, the formulation of the intumescent is important. Additionally, lower BR contents in the FRS series and lower FPS contents in the FRD series further enhanced flame retardancy. Advanced investigation by IR and ³¹P NMR demonstrated that lower BR and FPS content extends the survival duration of the phosphor-carbonaceous structure of chars. The findings in this study enhance the state-of-the-art understanding of the effect of the intumescent.     

桉木胶合板生产工艺的研究

在试验与生产结合的情况下,通过正交方法研究了桉木胶合板的制造工艺,运用极差和方差联合进行分析,得出了桉木生产的最佳工艺参数,即桉木的涂胶量是290g/m2,热压时间是1.9min/mm,热压压力1.4MPa,热压温度是115℃,在此参数组合下,桉木胶合板的性能达到最好,其耐水胶合强度满足Ⅱ类胶合板的要求,为1.89MPa,静曲强度54.45MPa,弹性模量7071MPa.     

Cooling effect of MWCNT-containing composite coatings on cotton fabrics

Multiwalled carbon nanotubes (MWCNTs) were dispersed in an aqueous solution of epichlohydrin based resin with the aid of a surfactant. The MWCNT-resin solutions were applied onto cotton fabrics to form a thin coating with different MWCNT contents (0, 11.1, 20.0, 33.3, and 50%). The thermal conductivity of the fabrics was measured based on the Newton’s law of cooling. The coating containing 50% MWCNTs showed 151% increase in the thermal conductivity. Infrared thermography was used to characterize the heating/cooling behavior of the fabrics. On contact with a 50°C hot surface, coated fabric that had 50% MWCNTs in the coating layer showed a 3.9°C lower equilibrium surface temperature than the untreated fabric. The cooling rate increased with increasing the MWCNT content within the coating layer. Such an effective cooling performance was attributed to the increased thermal conductivity and surface emissivity of the MWCNT-containing coating layer. The coating showed little influence on water contact angle of the coated fabrics, but slightly decreased the air permeability.     

Suppression of arsenopyrite surface oxidation by sol-gel coatings

Oxidation of arsenopyrite (FeAsS) in mine tailings is considered as the major cause of arsenic release in groundwater around mineral mine sites. Oxidation rate is increased by the biooxidation of chemolithoautotrophic bacteria, such as Acidithiobacillus ferrooxidans via the adsorption mechanism. Hence, coating with thin films as a physical barrier for oxidants surrounding the mineral surface is one of the effective abatement strategies. In this work, we studied and characterized the formation of thin films using sol-gel on arsenopyrite and investigated the resistance of thin films to biological and chemical oxidations. We selected methyltrimethoxysilane (MTMOS), tetramethoxysilane (TMOS), tetraethoxysilane (TEOS) and N-(2-aminoethyl)-3-aminopropyl trimethoxysilane (AAPS) as sol-gel precursors. MTMOS coating arsenopyrite particles at a H2O/Si molar ratio of 2 suppressed both biological oxidation and chemical oxidation and was superior to other alkoxysilane monomers. Factors involved in oxidation suppression are the crack-free morphology and the hydrophobicity of MTMOS coating. The Si-O-Si spectrum by Fourier transform infrared (FTIR) distinctly found for the MTMOS film is considered to indicate the formation of the networks of the film, and the Fe-O-Si spectrum confirmed the bonding of the film to the arsenopyrite surface.