乳酸菌素复合抗菌膜的制备及其在冷鲜猪肉保鲜中的应用

【目的】制备含有Nisin和植物乳杆菌素BM-1复合抗菌剂的包装薄膜,并观察其包装冷鲜猪肉在4℃条件下的品质变化。【方法】通过薄膜载体材料壳聚糖和羟丙甲基纤维素(HPMC)分别将乳酸菌素Nisin或乳酸菌素Nisin-植物乳杆菌素BM-1复合抗菌剂涂布至PE/PVDC/RCCP(PPR)塑料膜上,制备抗菌薄膜。利用该抗菌薄膜包装冷鲜猪肉,置于4℃条件贮藏,观察不同抗菌薄膜对冷鲜猪肉菌落总数(需氧菌和厌氧菌)、pH值和挥发性盐基氮值(TVB-N)的变化。【结果】冷鲜猪肉贮藏过程中,Nisin-BM-1-PPR复合型抗菌薄膜可抑制冷鲜猪肉中的菌落总数增长、维持pH稳定和降低TVB-N值升高。【结论】Nisin-BM-1-PPR复合型抗菌薄膜对冷鲜猪肉的保鲜作用至少8d以上,而Nisin-PPR抗菌薄膜只能作用4d。     

冷冻调理食品的包装及冻结

一、包装的方法及形式 　　1.真空袋包装 　　取代将内容物充填到成型塑料盒小袋包装的另一种形式是真空袋包装，这在冷冻食品中广泛被使用。其优点是对个体较为厚重的食品 (比如猪蹄或大丸子等 )，这种紧密包装，会给消费者感官产生一定的价值感。真空自动包装设备容易操作，外观效果好，调理方便。另外一种方式是采用全自动化的新型设备，分别由设备将上部薄膜和下部薄膜加以组成包装，充填的内容物首先被放置有下部薄膜的机器上，然后与上部薄膜进行第一次三面封口，然后进行抽真空，紧接着再进行第二次封口、切断的连续操作。在国外，…     

牛至精油聚乙烯醇抗菌薄膜的制备及其抑菌活性研究

[目的]制备一种以聚乙烯醇为基材,以牛至精油为抑菌剂的新型抗菌薄膜。[方法]采用气相色谱-质谱(GC-MS)分析鉴定了牛至精油的化学成分,将其与聚乙烯醇、玉米淀粉等制备抗菌薄膜,并且研究其力学性能、透光率、雾度及抗菌效果。[结果]牛至精油的主要化学成分是香芹酚,占84.40%;牛至精油可提升抗菌薄膜的断裂拉伸应变,但降低了抗菌薄膜的拉伸强度;随着牛至精油的添加,抗菌薄膜的透光率降低,雾度升高;抗菌薄膜的抑菌活性随着牛至精油添加量的增加而逐渐增强。[结论]当牛至精油的添加量为2%时,可以制备出一种抑菌性能和力学强度都较好的抗菌薄膜。该抗菌薄膜对灰霉、青霉、根霉的抑菌圈直径分别为60、45、90 mm。     

新型脂质--淀粉基可食膜的研究

可食性包装膜是以天然可食性物质(蛋白质、多糖、纤维素及其衍生物)为原料，通过不同分子间相互作用形成的具有多孔网络结构的薄膜。可食性包装膜的使用性能与合成塑料包装膜一样，更具有无法比拟的优越性，如(1)明显的阻隔性，可延缓食品中水和油及其它成分的迁移和扩散。(2)具有良好的机械性能，可增加食品表面抗冲击强度。(3)可与被包装食品一起食用，对食品和环境无污染等。     

漫话保鲜膜

<正>食品用塑料自粘保鲜膜,简称保鲜膜,是指用于包装食品时,具有自粘功能和食品保鲜或保洁功能的一类薄膜。作为一种厨房用品,保鲜膜在家庭中的使用日益得到普及。保鲜膜的分类按照所用材料,可将目前市面上出售的保鲜膜分为聚乙烯自粘保鲜膜、聚氯乙烯自粘保鲜膜和聚偏二氯乙烯自粘保鲜膜三类。其中,聚乙烯自粘保鲜膜是指以聚乙     

改性PDMS薄膜的制备及其抗菌性能研究

为了改进聚二甲基硅氧烷(PDMS)薄膜的抗菌能力,选择具有低表面能的PDMS作为研究对象,分别使用三氟乙酸(TFA)、钛酸四丁酯(TBT)以及二者的混合物对其进行改性.采用覆膜法,以大肠杆菌Echerichia coli作为供试菌种,对改性后的PDMS薄膜进行抗菌性能检测.结果表明:改性后的薄膜在短时间内表现出较强的抗菌性,使用TBT以及TFA与TBT混合物改性的PDMS薄膜经紫外照射后抗菌性明显提高.     

不同薄膜包装对鲜切芹菜货架期品质的影响

以新鲜香芹(Apium graveolens L.)为材料,研究了不同厚度薄膜对鲜切芹菜贮藏效果的影响。结果表明,薄膜包装可延缓鲜切芹菜的失重、黄化等,其中P3薄膜效果最为理想。P3薄膜[32.7μm聚乙烯袋,CO2渗透系数31 616.57 m L/(m2·d),O2渗透系数4 329 m L/(m2·d)]包装可在包装袋内形成高浓度CO2、低浓度O2环境,提高芹菜贮藏品质。P3薄膜包装对鲜切芹菜保鲜效果最佳。     

纳米银抗菌膜对白菜的保鲜效果

为了获得纳米银抗菌膜对白菜的最佳保鲜效果,研究不同纳米银添加量(0、2%、3%、4%、5%、6%、7%)的聚乙烯薄膜对白菜上所携带微生物的抗菌效果,以及对白菜贮藏保鲜过程中失质量率、色差、新鲜度、袋内CO2、O2含量等指标的影响。结果表明,抗菌试验中,4%纳米银含量的薄膜对白菜上菌群的抗菌率达91.2%,已经对绝大多数的菌落产生了抑制作用;白菜保鲜试验中,纳米银含量达到4%的薄膜对降低白菜的失质量率、叶片黄化,保持白菜的新鲜度有一定的效果,而纳米银的添加对改善薄膜的气调作用没有效果。综合结果,在白菜的包装保鲜中,薄膜中纳米银的最佳添加量为4%。     

软罐头食品开发前景广阔

软罐头食品是指用软性材料薄膜包装、密封,经过杀菌处理的包装食品,具有节能省时、维生素 C 损失少、保鲜能力强、适用范围广、便于贮运等优点。小袋包装软罐头便于1～2人消费,适应现代家庭的饮食习惯,     

释放型抗菌包装技术在食品防腐保鲜中的应用

随着我国经济的快速发展,消费者对食品安全及营养健康的要求不断提高,创新食品防腐保鲜方式已成为现代食品工业发展的重点方向。在消费市场的驱动下,食品防腐保鲜与抗菌包装技术得到迅速发展,该技术在延长食品保藏期、维持良好感官及食用品质方面取得较好的效果。本文总结概括了几种抗菌包装技术方法,并指出不同方法之间的优缺点,用以指导生产实践工作。     

Antimicrobial and Photocatalytic Effect of Silicate and Silicone Hygienic Coatings

Antimicrobial and photocatalytic effect of silicate and silicone paints were tested. Silicate paints are based on water styrene-acrylic dispersion with mineral binder into form of potassium water glass. Silicone paints are based on water acrylic dispersion with silicone resin emulsion. Silicate and silicone paints were formulated with photocatalytic active nanooxides TiO2 and ZnO. Photocatalytic efficiency of coatings was measured as an absorbance change of organic dye Orange II solution at a wavelength of 485 nm. Antimicrobial properties of coatings were tested using agar plate methods. As test microorganisms Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Penicillium chrysogenum and Aspergillus niger suspension （density 10^6 cells/mL） were used. The inhibition effect of tested coatings and inhibitory zones were evaluated after incubation. Coatings containing nanoparticles of titanium dioxide and zinc oxide showed antimicrobial activity against the test microorganisms. Whereas coating with zinc oxide nanoparticles successfully inhibited the growth of both bacteria and fungi, the photocatalytic nanoparticles of titanium dioxide inhibited bacteria but not fungi （weak inhibition was observed）.     

Super-compressible foamlike carbon nanotube films

We report that freestanding films of vertically aligned carbon nanotubes exhibit super-compressible foamlike behavior. Under compression, the nanotubes collectively form zigzag buckles that can fully unfold to their original length upon load release. Compared with conventional low-density flexible foams, the nanotube films show much higher compressive strength, recovery rate, and sag factor, and the open-cell nature of the nanotube arrays gives excellent breathability. The nanotube films present a class of open-cell foam structures, consisting of well-arranged one-dimensional units (nanotube struts). The lightweight, highly resilient nanotube films may be useful as compliant and energy-absorbing coatings.     

UV自由基固化和阳离子固化涂层的比较研究

对 U V自由基固化和阳离子固化两种机理进行了对照试验 .考察了温度和 O2 对固化速度的影响 ,涂层性能及它们作为 UV固化涂料、油墨的优缺点 ,并从理论上进行了分析 .U V自由基固化和阳离子固化的固化速度随温度的升高而加快 ,并且自由基的固化速度大于阳离子固化速度 .自由基固化体积收缩大 ,附着力差 ;阳离子固化体积收缩小 ,附着力优异 .氧对自由基固化有显著的阻聚作用 ,而对阳离子固化没有阻聚效应 .此外 ,阳离子固化存在“暗反应”,当移走 UV光源后 ,仍会发生固化反应     

虾类生物保鲜膜的制备技术研究

以凡纳滨对虾为原料,采用茶多酚、海藻酸钠、甘油、硬脂酸等成分为成膜材料,对生物抗菌膜的组分配比和制膜工艺进行研究。结果表明：茶多酚浓度15 g/L、海藻酸钠浓度20 g/L、甘油浓度0.4%、硬脂酸浓度15 g/L的组分配比以及在膜液pH 5.5、存放环境RH〈50%的条件下制备的膜具有良好的机械抗菌性能。经过上述条件生产的抗菌膜对凡纳滨对虾及其虾仁具有良好的保鲜效果,虾类保鲜期延长3~4 d,虾仁持水力和感官品质得到不同程度的提高。     

脉冲偏压电弧离子镀CrN薄膜的表面形貌和性能研究

采用脉冲偏压电弧离子镀技术沉积了CrN薄膜,并考察了在不同偏压下薄膜的表面形貌、相结构、显微硬度和耐磨性．随着偏压的增加,CrN薄膜表面颗粒逐渐变少,表面粗糙度降低,结晶度增大,偏压为-100V的CrN薄膜具有致密的表面结构,较高的硬度,最佳的抗磨性能．     

Mussel-inspired surface chemistry for multifunctional coatings

We report a method to form multifunctional polymer coatings through simple dip-coating of objects in an aqueous solution of dopamine. Inspired by the composition of adhesive proteins in mussels, we used dopamine self-polymerization to form thin, surface-adherent polydopamine films onto a wide range of inorganic and organic materials, including noble metals, oxides, polymers, semiconductors, and ceramics. Secondary reactions can be used to create a variety of ad-layers, including self-assembled monolayers through deposition of long-chain molecular building blocks, metal films by electroless metallization, and bioinert and bioactive surfaces via grafting of macromolecules.     

The ultrasmoothness of diamond-like carbon surfaces

The ultrasmoothness of diamond-like carbon coatings is explained by an atomistic/continuum multiscale model. At the atomic scale, carbon ion impacts induce downhill currents in the top layer of a growing film. At the continuum scale, these currents cause a rapid smoothing of initially rough substrates by erosion of hills into neighboring hollows. The predicted surface evolution is in excellent agreement with atomic force microscopy measurements. This mechanism is general, as shown by similar simulations for amorphous silicon. It explains the recently reported smoothing of multilayers and amorphous transition metal oxide films and underlines the general importance of impact-induced downhill currents for ion deposition, polishing, and nanopattering.     

Using selective withdrawal to coat microparticles

We report a method that uses the process of selective withdrawal of one fluid through a second immiscible fluid to coat small particles with polymer films. Fluid is withdrawn through a tube with its orifice slightly above a water-oil interface. Upon increasing the flow rate, there is a transition from a state where only oil is withdrawn to a state where the water, containing the particles to be coated and appropriate prepolymer reagents, is entrained in a thin spout along with the oil. The entrained particles eventually cause the spout interface to break, producing a thin coat of controllable thickness around each particle, which can be subsequently polymerized using chemical reagents, light, or heat. This method allows flexibility in the chemical composition and thickness of the conformal coatings.     

长输管道外防腐层的选择

对长输客道防腐层的质量标准及应具备的性能进行了分析，总结了近期国内外管道防腐层的应用情况。近年来我国长输管道选用的防腐层以煤焦油瓷漆，聚乙烯二层或三层结构占多数，对各种防腐覆盖层的性能，适应条件以及优缺点进行了分析比较，提出了防腐层的选用原则。