纳米氧化锌在食品领域中的应用及安全性 研究进展

纳米氧化锌因其具有良好的抗菌性能已成为目前抗菌材料的研究热点。然而,随着纳米氧化锌在食品包装材料和食品添加剂等领域的广泛应用,其将不可避免地进入到生物体内,从而对人体健康造成一定危害,因此其生物安全性也引起了广泛关注。本文通过总结和归纳相关的研究报道,阐述了纳米氧化锌在食品领域的应用,并介绍了其可能引起的遗传、免疫、生殖、神经等毒性效应,深入探讨了纳米氧化锌相关毒性的影响因素,以期为今后纳米氧化锌在食品领域的研究和应用提供参考。     

基于纳米粉体的织物抗紫外线研究

通过纳米粉体反射光谱和纳米树脂薄膜紫外线透过率的测试，筛选出的纳米粉体．应用到棉织物上，使得织物抗紫外线性能符合抗紫外线标准要求．研究结果表明，丙烯酸树脂对UVA波段吸收较强；二甲苯含量对紫外线透过率有一定影响；对于相同厚度的膜，二甲苯比例越大，紫外线透过性能越好．随着纳米粉体含量增加，纳米膜抗紫外线效果会增强．对于ZnO、TiO2纳米粉体，波长320nm的紫外线透过率与纳米粉体含量呈负指数关系，当添加量达到4％以后，棉织物的紫外线透过率在0．5％以下。     

改性纳米二氧化钛的性能研究

研究了改性纳米二氧化钛在乙二醇介质中的稳定性及其影响因素和应用性能.结果表明，改性纳米二氧化钛溶胶的稳定性与改性剂的用量和体系pH值有关，在大于等电点时，随体系pH值的增加，溶胶的稳定性提高.红外光谱和应用性能研究表明，由于在改性纳米二氧化钛微粒表面引入了大量的硅羟基和环氧基等基团，织物经其整理后，抗紫外线等性能的耐久性有很大提高，且随着纳米改性剂用量的增加，耐久性逐渐提高.     

超细TiO_2、ZnO等粉体材料在功能型纺织品开发中的应用

介绍了超细陶瓷粉体TiO2 、ZnO的物化性能及其在功能型纺织品开发中的潜在价值、加工处理方法和检测手段     

Investigating the effect of corona treatment on self-cleaning property of finished cotton fabric with nano titanium dioxide

This research aims to create the durable self-cleaning property on cotton fabric using nano titanium dioxide and corona treatment as a dry and environmentally friendly process. In this regard, cotton fabrics were investigated under corona treatment with intensities of 2 and 3 A for 1, 3, and 5?min of irradiation. The treated samples with 0.1, 0.5, 1, and 1.5 on weight of bath percent were cured by nano titanium dioxide to obtain the highest self-cleaning property. The treated cotton fabrics, which were stained with direct green 6, were exposed to 20 and 400?W of UV radiation and their self-cleaning property was examined, and the results were reported. In addition, using corona treatment helped to stabilize the nano titanium dioxide on the cotton fabric surface even after 50 washing cycles. Through SEM images, Thermo Gravimetric Analysis plots, and XRD patterns, the presence of nano titanium dioxide on the surface of the treated cotton samples after washing was verified. Also, the tensile strengths of TiO₂-coated cotton fabrics were measured.     

Field trials on the efficacy of Beauveria bassiana,diatomaceous earth and Imidacloprid for the protection of wheat grains from four major stored grain insect pests

We assessed the insecticidal efficacy of Beauveria bassiana, diatomaceous earth (DE) and the neonicotinoid Imidacloprid against four major insect species of stored grain pests during field trials conducted on small farms located in four districts of Punjab, Pakistan. In each district, a 40 kg lot of wheat grain was admixed with B. bassiana (3 × 10¹⁰ conidia kg⁻¹), DE (150 ppm) and Imidacloprid (5.0 ppm) alone and in different combinations. Each lot was divided subsequently into four equal parts (10 kg each), packed in polypropylene bags, artificially infested, labeled and stored at the farms under natural environmental conditions up to 6 months. Sampling was carried out every 30 d to record the total number of dead and alive adults, as well as the percent of grain damage in treated and untreated (control) grains. Results revealed a significant difference among the treatments, test insect species and the storage period. For each district, the combined treatments provided better control of all tested insect species compared with each treatment alone. The least number of surviving adults and minimum percent grain damage was observed for Imidacloprid and DE combination, but was outperformed by the DE treatment with B. bassiana for long-term protection. For all grain protectants, we obtained the same order of susceptibility level among the test species (i.e. Liposcelis paeta > Cryptolestes ferrugineus > Rhyzopertha dominica > Tribolium castaneum). The results of the present study suggested that DE, insect pathogenic fungi and Imidacloprid can be effectively used for the protection of wheat stored at small-scale farmer's fields.     

Prevalence of resistance to deltamethrin in Rhyzopertha dominica (F.) in eastern Australia

The pyrethroid, deltamethrin, is currently used as a grain protectant to protect stored grain from insect pests in several countries including Australia. We examined the variation in response to wheat treated with deltamethrin among 15 field populations of the lesser grain borer, Rhyzopertha dominica (F.) collected from Queensland and New South Wales in eastern Australia during 2008 and 2009, to establish whether resistance has developed in this species. Based on the results of treated wheat bioassays, using a discriminating dose of 0.5 mg kg⁻¹, we found that 14 of the 15 field populations were resistant to deltamethrin. The distance between the two most geographically separated field populations was 450 km, and both of these populations contained resistant insects. Deltamethrin applied at 1 mg kg⁻¹ alone or with the synergist piperonyl butoxide at 8 mg kg⁻¹ failed to control resistant R. dominica. On the basis of our findings, we conclude that populations with deltamethrin resistant individuals are common in the eastern part of Australia, and control failures are expected when such populations are present in treated grain.     

Comparative toxicity of nanostructured alumina and a commercial inert dust for Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) at varying ambient humidity levels

The widespread concern for environmental and human health has raised the need for new reduced-risk control strategies and the search for new chemical classes of pesticides. Recently, a novel type of particulate material, nanostructured alumina (NSA) has been found to induce mortality in insects exposed to wheat treated with NSA dust. Preliminary studies have shown insecticidal activity of NSA particles on two insect species, Sitophilus oryzae (L.), and Rhyzopertha dominica, (F.), major pests of stored grain. We investigated the toxicity of NSA and Protect-It^® diatomaceous earth (DE) using dry dust applications at three different relative ambient humidity levels. Results showed that NSA was more effective in killing S. oryzae than Protect-It^® and was equally toxic to R. dominica. Treatment with both products also reduced progeny production. In addition, R. dominica was less susceptible to inert dusts than S. oryzae. Our results suggest that NSA might prove a good alternative or complement to DE based products, and encourage further testing with other insect pests and systems, plus experiments on delivery options to further enhance NSA products.     

纳米氧化锌在抗菌食品包装中的应用研究进展

食品包装技术在保障食品安全及保持食品品质方面发挥着重要作用,如何增强食品包装材料的抗菌能力因此成为近年来研究的热点。纳米氧化锌是一种常见的无机抗菌材料,对大肠杆菌和金黄色葡萄球菌等细菌及真菌具有良好的抗菌效果。本文在比较目前各类抗菌食品包装的基础上,综合分析了纳米氧化锌的抗菌机理及其在抗菌食品包装中的特性及应用。     

Base-line susceptibility of field populations of Rhyzopertha dominica (F.) to spinosad in Australia

Spinosad has recently been registered in several countries for long-term protection against a range of stored grain insects including the lesser grain borer, Rhyzopertha dominica (F.). The potential for development of resistance to spinosad is demonstrated by the existence of resistance in many insect pests of agriculture. The aim of this study was to determine the base-line susceptibility of R. dominica to spinosad, to provide a basis for future resistance monitoring. Eighteen insect populations of R. dominica were collected from field storage sites across four States within Australia, and exposed to a range of spinosad rates, including its current registered rate of 1 mg kg⁻¹ (1 ppm). Base-line susceptibility was assessed based on adult mortality and production of F₁ adults. Comparison of LC₅₀ and LC_99.9 indicated the existence of low level of variation among the tested R. dominica populations, in their susceptibility to spinosad. For adults, there was a narrow range of LC₅₀ values with the highest (0.027 ppm) being 2.5 × the lowest (0.011 mg kg⁻¹). Similarly, LC_99.9 values showed a narrow range with the highest (0.36 mg kg⁻¹) being 3.6 × the lowest (0.10 mg kg⁻¹). For adult progeny produced in spinosad treated grain, there was a narrow range of LC₅₀ values with the highest (0.025 mg kg⁻¹) being 5 × the lowest (0.004 mg kg⁻¹) and the highest LC_99.9 values (0.67 mg kg⁻¹) being 5 × the lowest LC_99.9 (0.13 mg kg⁻¹). Based on the data generated from this study, we recommend a dose of 1 mg kg⁻¹(1 ppm) to be used to discriminate between susceptible and resistant populations for future resistance monitoring programs.     

Modified Rice Straw as a Template in Syntheses of Nano TiO2 Loaded on Wool Fibers for Wastewater Treatment

Industrialization of textile produces large amounts of colored wastewater and recycling of that wastewater is recently under the scope. The current work is implemented to use rice straw as a template for preparation of nano TiO₂ to be applied in decolorization of wastewater of textile industries. Different treatments including silica removal and esterification were performed for rice straw to produce highly reactive nanotitanium dioxide. Size, morphological shape, and surface area of the so obtained TiO₂ nanoparticles were observed to be influenced by rice straw treatments. Percentage of anatase phase in titanium dioxide was increased from 41.6% to 75.0% after removing of silica and modification with citric acid of rice straw. The particle size of anatase was significantly reduced from 88.6 nm to 10.5 nm while the BET surface area of nanotitanium dioxide was enlarged from 41.2 m²/g to 84.7 m²/g. The prepared TiO₂ nanoparticles were loaded onto wool fibers and the photocatalytic properties of nano TiO₂ powder before and after loaded to fiber were measured against methylene blue dye. The dye removal percentage raised from 92.5 to 99.2 by using of nano TiO₂ powder-loaded wool fibers compared to nano TiO₂ powder.     

The disappearance of photocatalytic properties of titanium dioxide nanoparticles formed on PET fabrics treated in a simultaneous hydrothermal-dyeing process

In this paper, the influences of dyestuff Disperse Blue 79 and corresponding dyeing auxiliaries on the microstructure and the photocatalytic activities of titanium dioxide nanoparticles formed on polyethylene terephthalate (PET) fabric modified with tetrabutyl titanate in a simultaneous hydrothermal-dyeing process are studied. In contrast to the apparent photocatalytic activities of the crystalline titanium dioxide particles formed in the solely hydrothermal process using tetrabutyl titanate, the titanium dioxide nanoparticles formed in the simultaneous hydrothermal-dyeing process is non-crystalline and is covered with a layer of organic substances. It is thus concluded that the microstructure of the as-synthesized titanium oxide nanoparticles is greatly influenced by the presence of dyestuff and its corresponding dyeing auxiliaries. It is also found that these resultant non-crystalline titanium oxide nanoparticles in the simultaneous hydrothermal-dyeing process do not show any photocatalytic activity; the disappearance of the photocatalytic activity of the resultant titanium oxide nanoparticles in the simultaneous hydrothermal-dyeing process might be due to both their non-crystalline microstructure and their surface coating of organic substances.     

Preparation,characterization, and functional analysis of zinc oxide nanoparticle-coated cotton fabric for antibacterial efficacy

Nanotechnology is an emerging interdisciplinary technology and nanostructures capable of enhancing the physical properties of conventional textiles in areas such as antimicrobial properties, water repellence, soil resistance, antistatic, anti-infrared and flame-retardant properties, dye ability, color fastness, and strength of textile materials. The studies were carried out in order to fine tune the preparation of zinc oxide nanoparticles (NPs) for special applications. Soluble starch (stabilizing agent), zinc nitrate and sodium hydroxide (precursors) were used for the preparation of zinc oxide NPs by wet chemical method. The synthesized NPs were coated on cotton fabric (plain weave), and the antibacterial property of the treated fabric was analyzed. Fourier transform infrared spectroscopic analysis, scanning electron microscopy, and physical and chemical characterization were employed to determine the phase and morphology of the final nanoparticle-coated fabric. The results indicated that 2% zinc oxide nanoparticle (200 nm) -coated fabric have high antibacterial efficiency (99.9% against Staphylococcus aureus and 80% against Escherichia coli) and upon washing the coated fabric (five hand washes), the antibacterial activity was found to be 98% against S. aureus and 75% against Escherichia coli.     

氧化锌纳米颗粒-海藻酸钠/壳聚糖双层复合膜的制备及特性

本研究基于层层组装流延法制备了载有氧化锌纳米颗粒的海藻酸钠/壳聚糖双层复合膜。通过评价机械、阻水及光学性质研究了氧化锌纳米颗粒对双层复合膜特性的影响,进而借助原子力显微镜、扫描电子显微镜、傅里叶变换红外光谱和热重分析对双层复合膜结构进行表征。结果表明,海藻酸钠/壳聚糖双层膜在添加氧化锌纳米颗粒后,抗拉强度提高,断裂伸长率、水溶性、水蒸气透过性和透光性降低,而外观色泽没有明显变化。从双层膜的微观结构看,随着氧化锌纳米颗粒添加浓度由0.25%（w/w）增加至1.00%（w/w）,海藻酸钠/壳聚糖双层复合膜表面出现颗粒团聚,粗糙度Ra从3.12 nm增加至3.53 nm。红外和热重分析表明,氧化锌纳米颗粒与海藻酸钠和壳聚糖之间存在较强的氢键相互作用,使得双层复合膜的热稳定性增强。综上,氧化锌纳米颗粒-海藻酸钠/壳聚糖双层复合膜具有优良的包装特性和适用性。     

纳米氧化锌表面改性及应用研究

讨论了纳米氧化锌的制备方法及影响因素。并比较了聚乙二醇PEG-400、不饱和脂肪酸Tween-60和低聚丙烯酸钠PAAS三种表面改性剂对氧化锌颗粒大小及表观形态的影响。试验表明，聚乙二醇能有效地降低颗粒尺寸，而采用Tween-60和PAAS能得到分散性良好的纳米氧化锌。改性后的纳米氧化锌的抗紫外和抗菌性都有明显提高。     

纳米氧化锌对金黄色葡萄球菌的抑制及其作用机制研究

目的 研究纳米氧化锌对金黄色葡萄球菌的抑制及其作用机制。方法 统计金黄色葡萄球菌在含有0.5、1.0、1.5、2.0和4.0 mg/mL纳米氧化锌的胰蛋白胨大豆肉汤中的活细胞数目, 不同质量浓度纳米氧化锌处理金黄色葡萄球菌后, 分别采用扫描电镜和透射电镜观察细胞形态和超微结构的变化, 并分析细胞中活性氧(O2-)含量及超氧化物歧化酶(superoxide dismutase, SOD)活性的变化。结果 纳米氧化锌可显著抑制金黄色葡萄球菌的生长(P<0.05), 当纳米氧化锌的质量浓度为2.0 mg/mL时, 培养24 h后金黄色葡萄球菌的数目比不加纳米氧化锌的对照组低5.2 logCFU/mL (P<0.05)。经纳米材料处理后, 金黄色葡萄球菌的菌体外形虽然未发生明显改变, 但细胞内部的组织结构遭受严重损伤, 细胞膜结构模糊, 胞内的O2-含量显著升高(P<0.05), SOD酶活性在处理后期显著降低(P<0.05)。结论 纳米氧化锌的处理可使金黄色葡萄球菌菌体细胞组织结构和细胞膜发生损伤, 并导致细胞产生了氧化应激反应, 从而抑制其增殖。     

Functional finishing of cotton fabrics using graphene oxide nanosheets decorated with titanium dioxide nanoparticles

This study examined an innovative approach for imparting multi-functional properties, i.e. self-cleaning, electrical conductivity, ultraviolet (UV) blocking as well as antimicrobial properties onto cotton fabric. Graphene oxide/TiO₂ nanocomposites were successfully prepared, by a simple method of mixing and sonication, and used for multi-functional treatment of cotton fabrics by dip-drying technique. The physicochemical properties of the prepared samples were characterized with field emission scanning electron microscope, transmission electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy. Self-cleaning performance, electrical resistance, antimicrobial properties, and UV blocking activity of treated fabrics were also assessed. The coated cotton fabrics with graphene oxide/TiO₂ nanocomposite showed excellent photocatalytic self-cleaning activity measured by degradation of methylene blue in aqueous solution under sunlight irradiation. Results showed that the electrical conductivity of the graphene oxide/titanium dioxide nanocomposite-coated fabrics was improved significantly after sunlight irradiation. Moreover, the nanocomposite finished cotton fabric demonstrated proper antimicrobial properties and UV blocking activity.     

Effectiveness of diatomaceous earth for control of Sitophilus zeamais (Coleoptera: Curculionidae), Tribolium castaneum and Palorus subdepressus (Coleoptera: Tenebrionidae)

The effectiveness of diatomaceous earth (DE) or diatomite has been assessed against three major beetle pests of stored maize: Sitophilus zeamais (the maize weevil), Tribolium castaneum (the red flour beetle) and Palorus subdepressus (the depressed flour beetle). Maize has been treated with four doses of DE (1.5, 3, 4.5 and 6 g/kg) and four doses of Actellic Super™ Dust a chemical insecticide used as a reference (0.25, 0.5, 0.75 and 1 g/kg). The effective mortality was measured for each treatment after 1, 2, 4, 7 and 14 d of exposure. The corrected mortality rates were calculated by considering the mortality in the control group. Diatomaceous earth was as effective as Actellic Super™ Dust but required higher doses. Diatomaceous earth acted faster on S. zeamais and P. subdepressus compared to T. castaneum. The highest dose tested for DE caused the same mortality in T. castaneum as the recommended dose of Actellic Super™ Dust. Diatomaceous earth is a good alternative for the control of these three devastating insect pests of maize stocks and can readily be incorporated into integrated stored products pest management programs.     

Lethality and kinetic of diatomaceous earth uptake by the bean weevil (Acanthoscelides obtectus [Say] Coleoptera: Bruchinae): Influence of short-term exposure period

Laboratory bioassays were carried out to assess the lethal effect of the diatomaceous earth (DE) formulation Fossil-Shield® against males and females of adult bean weevils (Acanthoscelides obtectus [Say]). Kinetics of the DE uptake experiment was determined by using manganese as a trace element. The adherence of DE to the common bean was also measured in this study. The mortality of weevils was evaluated after exposure to eight different DE dosages (400–4000 mg/kg) after 1, 2 and 4 days, respectively. DE dust was more lethal to male than female weevils within shorter exposure period at low DE dosages (<2400 mg/kg). However, LD₉₉ values did not show a significant difference (P > 0.05) between sexes. DE adherence ratio ranged between 73% and 98% at the highest (3600 mg/kg) and the lowest (400 mg/kg) DE dosages, respectively. The maximum saturated amount of DE retention on the bean surface was approximately 7.14 μg/mm². The amount of DE uptake by a weevil was significantly increased (P < 0.05) with DE dosage and exposure time. The two-compartment kinetic model fitted well to the experimental data as a two-site reaction model over the range of DE dosage between 500 and 2000 mg/kg. According to the model, bean weevils can take-up 2.3–3.1 μg/mm² of DE based on their corresponding LD₉₉ values depends on the exposure period. It was observed that DE particles were incorporated into the epicuticle lipid layer at a rate of 1.18 × 10⁻³ μg mm⁻² min⁻¹ during DE uptake by a weevil. This indicates that from the total body weight, approximately 2% of DE taken-up by an insect within a given exposure period was more decisive for insect mortality than the rate of DE application.     

Antimicrobial agent detection in ewes’ milk by the microbial inhibitor test brilliant black reduction test—BRT AiM®

The detection limits of 24 antimicrobial agents were determined in ewes’ milk by one commercially available version of brilliant black reduction test, BRT Inhibitor Test with prediffusion AiM^® (BRT AiM^®). For each drug, eight concentrations were tested on 20 milk samples from individual ewes. The detection limits of the BRT AIM^® method were determined by means of logistic regression models: 6 μg kg⁻¹ amoxycillin, 6 μg kg⁻¹ ampicillin, 51 μg kg⁻¹ cloxacillin, 2 μg kg⁻¹ penicillin “G”, 230 μg kg⁻¹ cefadroxil, 1330 μg kg⁻¹ cephalosporin “C”; 270 μg kg⁻¹ cephalexin, 92 μg kg⁻¹ cefoperazone, 120 μg kg⁻¹ ceftiofur, 69 μg kg⁻¹ cefuroxime, 6000 μg kg⁻¹ streptomycin, 1200 μg kg⁻¹ gentamycin, 3700 μg kg⁻¹ neomycin, 630 μg kg⁻¹ erythromycin, 120 μg kg⁻¹ tylosin, 390 μg kg⁻¹ doxycycline, 5500 μg kg⁻¹ oxytetracycline, 6200 μg kg⁻¹ tetracycline, 5400 μg kg⁻¹ sulfadiazine, 3200 μg kg⁻¹ sulfamethoxazole, 6500 μg kg⁻¹ sulfamethoxypyridazine, 6200 μg kg⁻¹ sulfaquinoxaline, 22000 μg kg⁻¹ chloramphenicol and 4100 μg kg⁻¹ trimethoprim. The BRT AiM^® method presents detection limits for β-lactam antibiotics that are similar to those obtained as Maximum Residue Limits (MRLs) according to Regulation 2377/90 EEC as set out by the European Union. However, for other antimicrobial agents the estimated limits were higher than those of the EU-MRLs. It is therefore advisable to enhance the sensitivity of the method for the detection of the different antimicrobial groups or to develop a combined system of different microbiological inhibitor tests that would enable the detection of a greater number of antimicrobial agents.