探讨新鲜食品薄膜的包装功能

<正> 在现今社会追求方便的前提下,超级市场内出售的新鲜蔬菜和肉类越来越普及,并深受消费者的欢迎。对于这些新鲜食品来说,产品本身的质量固然重要,其使用的包装物料及容器,在保持食品新鲜上也起着重要的作用。因此,透明且具优质保鲜性能的薄膜包装便成为新鲜食品的理想包装材料。随着消费者对使用薄膜包装的新鲜     

Environmental assessment of a multilayer polymer bag for food packaging and preservation: An LCA approach

A screening of LCA for the evaluation of the damage arising from the life cycle of a bi-layer film bag for food packaging was carried out. Such packages are made of films obtained matching a layer of PA (Polyamide) with one of LDPE (Low-Density Polyethylene) and are mainly used for vacuum or modified atmosphere packaging and preservation of food. The study was conducted in accordance with the ISO standards 14040:2006 and 14044:2006 choosing, as the functional unit, 1 m² of plastic film delivered to the food production and packaging firms. The system boundaries go from cradle to factory-gate and include the phases of: the raw materials production and processing for the bag manufacturing; and the bag delivering to the food production and packaging plant.The damage assessment showed that the most impacting phases are the production of the Polyamide (PA6) and Low-Density Polyethylene (LDPE) granules due to the consumption of primary resources, such as natural gas and crude oil, in the amount of 53.55 dm³ and 132.42 g respectively, and to the emission in air of 295.73 g of carbon dioxide, 617 mg of nitrogen oxides, 12.1 mg of particulates, 349 mg of sulphur dioxide and 2.51 mg of aromatic hydrocarbons. The most affected damage category is Resources, followed by Climate Change, Human Health, and Ecosystem Quality.For minimising the total damage associated with the life cycle of the examined bag, the film thickness thinning and the use of a recycled PA granule were considered: the assessment showed that the two proposals allowed a reduction of about 25% and 15% (respectively) of the damage assessed.     

Individual wrapping of radishes with food packaging film

When ‘Taibai’ radishes were individually wrapped with food packaging film, they had a reduced weight and firmness loss and a decreased formation of internal sponginess. When stored at 1 °C, wrapped radishes lost 0.01% of their fresh weight per day when compared with the 0.28% weight loss per day for unwrapped radishes. When stored at 5 °C, wrapped radishes lost 0.02–0.03% of their fresh weight per day when compared with the 0.78% weight loss per day of unwrapped radishes. Wrapped radishes stored for 88 days at 5 °C or 165 days at 1 °C maintained their firmness better than unwrapped radishes. Wrapped radishes had significantly less internal sponginess than unwrapped radishes.     

食品包装用复合膜材质分析方法研究

目的 研究食品包装用复合膜材质的分析方法。方法 样品截面经包埋抛光后, 采用扫描电镜-能谱仪(scanning electron microscope-energy dispersive spectrometer, SEM-EDS)对样品层数及各层元素信息进行表征。样品经甲酸浸泡分层后, 采用傅里叶变换红外光谱仪(fourier transforminfrared spectroscopy, FT-IR)、差式扫描量热仪(differential scanning calorimetry, DSC)、SEM-EDS对分层后各层薄膜的红外特征吸收峰、熔点、元素信息进行表征。结果 确认该复合膜具有4层结构, 从外表面到内表面材质依次为PET层(厚度约13 μm)、PA层(厚度约16 μm)、铝层(厚度约10 μm)、PP/PE共混层(厚度约67 μm)。结论 通过溶剂剥离分层, SEM-EDS、FT-IR、DSC连用表征分析, 可以确认食品包装用复合膜的多层膜整体结构及每层薄膜材质。     

Safety by design of printed multilayer materials intended for food packaging

ABSTRACT

Printing inks are commonly used in multilayer plastics materials used for food packaging, and compounds present in inks can migrate to the food either by diffusion through the multilayers or because of set-off phenomena. To avoid this problem, the right design of the packaging is crucial. This paper studies the safety by design of multilayer materials. First, the migration from four different multilayers manufactured using polyethylene terephthalate (PET), aluminium (Al) and polyethylene (PE) was determined. The structural differences among materials such as the presence of inks or lacquer coatings as well as the differences in layers position allowed the study of a safety-by-design approach. Sixty-nine different compounds were detected and identified; 49 of them were not included in the positive list of Regulation EU/10/2011 or in Swiss legislation and 15 belong to Cramer class III, which means that they have a theoretical high toxicity. Some of the compounds related to ink composition were pyrene, a compound commercially used to make dyes and dye precursors and the antioxidant Irganox 1300. The application of external lacquers decreased the concentration of some migrants but also brought the potential for new migrants coming from its composition. A final risk assessment of the material allowed evaluating food safety for different food simulants and confirm it.     

基于生命周期评价的瓦楞原纸产品碳足迹评价

依据PAS 2050:2011,采用B2B的方法利用eFootprint系统,对以废纸为原料生产的瓦楞原纸产品进行碳足迹评价.评价结果表明,生产1000 kg瓦楞原纸所排放的温室气体量为1226.79 kg CO2e,其中废纸制浆和抄纸过程是温室气体(GHG)主要排放过程,分别占GHG排放量的32.6％和54.1％;G...     

富含浒苔多糖的可食性食品包装膜的研制

以浒苔多糖浸液为基料,测定了浒苔多糖浸液中多糖和蛋白质的含量,并以正交实验和综合平衡法确定浒苔多糖浸液与辅料成膜的最佳添加量,并对成品膜的抗拉强度、断裂生长率和透水率进行了检测.结果表明,100g浒苔粉使用10g的NaHCO3抽提多糖浸液,制成的多糖膜中含有浒苔多糖1g,蛋白质0.07g,磷脂0.2g,变性淀粉0.5g,CMC1g,甘油0.3g,明胶2g,膜的透水率为6.2%.     

Determination of bisphenol A in, and its migration from, PVC stretch film used for food packaging

Bisphenol A (BPA) is used as an additive in polyvinyl chloride (PVC) products, including stretch films used for food packaging. The BPA contents were investigated of several brands of stretch film bought locally but marketed internationally or throughout Spain and which were presumably produced at different manufacturing plants. Their major components were identified by FTIR (Fourier Transform Infrared Spectrometry) and horizontal attenuated total reflectance, and the migration of BPA from these materials into the standard European Union food simulants was determined by high-performance liquid chromatography (HPLC) using both fluorescence (FL) and ultraviolet (UV) detection, the identity of the analyte being confirmed by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). The two HPLC detection methods had different detection limits (30 μg l^-1 for UV, 3 μg l^-1 for FL), but afforded virtually identical BPA determinations for the samples tested. BPA contents ranging from 40 to 100 mg kg^-1 were found in three of the five PVC-based films analysed, and a content of 500 mg kg^-1 was found in a fourth; for these determinations, extraction into acetonitrile was used. In standard tests of migration into water, 3% acetic acid and olive oil over 10 days at 40°C, migration from a given film was in all cases greatest into olive oil. Migration from the films with non-zero BPA contents ranged from 3 to 31 μg dm^-2, values higher than those reported for many other food-contact materials, but lower than the European Union specific migration limit for BPA. PVC stretch film nevertheless may make a significant contribution to contamination of foodstuffs by BPA, and should be taken into account in estimating BPA intake or exposure to this substance.     

Antimicrobial food packaging film based on the release of LAE from EVOH

The aim of this work was to develop antimicrobial films for active packaging applications containing the natural antimicrobial compound LAE (lauramide arginine ethyl ester) in EVOH copolymers with different mol % ethylene contents (i.e. EVOH-29 and EVOH-44). EVOH-29 and EVOH-44 films were made by casting and incorporating 0.25%, 1%, 5%, and 10% LAE in the film forming solution (w/w with respect to polymer weight). Previously, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of LAE against Listeria monocytogenes, Escherichia coli, and Salmonella enterica were determined by a microdilution assay. The antimicrobial activity of the resulting films was tested in vitro against these microorganisms in liquid culture media. The activity of the films was also evaluated over time. The results showed that films containing 5% and 10% LAE produced total growth inhibition and viable counts decreased with 0.25% and 1% LAE. Finally, the effectiveness of the films was tested by applying them to an infant formula milk inoculated with L. monocytogenes and S. enterica and stored for 6 days at 4°C. The application of films with LAE to infant formula milk inoculated with L. monocytogenes reduced at the end of storage period about 4 log in case of 10% LAE and with S. enterica reduced 3.74 log and 3.95 log with EVOH 29 5% and 10%, respectively, and EVOH-44 5% and 10% LAE reduced 1 log and 3.27 log, respectively, at the end of storage. The antimicrobial capacity of EVOH-29 films was greater than that of EVOH-44 films in all the cases tested. In general, the films were more effective in inhibiting the growth of L. monocytogenes than S. enterica, this inhibition being more acute at the end of the storage time.     

食品包装塑料薄膜的机械性能及检测方法研究

柔软的塑料薄膜适用于各种各样的包装,食品包装材料的机械性能是产品在包装之后对产品进行保护的最基本性能,可以防止包装的破损与泄漏。本文阐述了食品包装塑料薄膜的主要机械性能,包括拉伸性能、剥离性能、热合性能、撕裂性能、冲击性能以及穿刺性能,并介绍了主要的食品包装塑料薄膜的机械性能检测方法,为食品包装技术的研究和新产品的开发提供参考。     

纤维板生命周期评价模式的构建

根据生命周期评价(LifeCycleAssessment,简称LCA)的原则和框架,构建了我国现有的纤维板生产系统在环境效益、经济效益和技术性能方面生命周期综合评价的模式。该模式为我国生产纤维板企业的老厂改造、新厂建设以及相关政策法规的制定提供依据和参考。本模式在评价过程中采用了层次分析方法,不仅选用了专家评分的定性给分法,而且还根据获取的数据运用定量给分的方法,使计算结果能够体现纤维板工程项目的实际情况。     

基于生命周期评价（LCA）的纸产品碳足迹评价方法

结合我国纸产品生产的特点,基于生命周期评价法(LCA),研究了我国纸产品碳足迹评价的方法,包括启动阶段、纸产品碳足迹计算和结果解释三个步骤.     

棉织品的生命周期影响评价

生命周期影响评价是生命周期评价的重要环节,本文在综合分析国际生命周期影响评价的基础上,针对我国棉织品生命周期过程的环境特点,建立了一套棉织品生命周期影响评价的模型与方法。它包括环境影响类型选取、影响评价模型构造、特征化结果说明等流程,从而为我国棉织品的生态设计和开发提供了可供参考的依据。     

纳米二氧化钛抗菌食品包装复合膜的研究进展

纳米二氧化钛具有较好的抗菌作用,且在传统包装材料中有较好的分散性,添加了纳米二氧化钛的食品包装薄膜具有较好的抗菌效果,能在一定程度上延长食品的保质期。目前,有较多关于纳米二氧化钛食品包装复合膜的研究,主要是围绕抗菌性,机械性能和安全性等方面展开,研究表明：纳米二氧化钛复合膜的抗菌性受光照影响;复合膜的机械性能、热力学性能和阻隔性等随纳米二氧化钛的加入有所改变;复合膜中的纳米二氧化钛可能会迁移到包装的食品中,造成食品安全隐患;制备复合膜时需综合考虑以上因素。本文主要对纳米二氧化钛的抗菌机理、纳米二氧化钛抗菌食品包装薄膜的制备和应用、纳米二氧化钛的迁移研究进展进行概述,旨在扩展纳米二氧化钛复合膜更好更安全地应用于食品包装。     

Experimental and theoretical study of thermodynamics and transport properties of multilayer polymeric food packaging

The specific migration of Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (I-1076) from three-layer low-density polyethylene plastic films into a fatty food simulant was studied. The film samples, having a symmetrical structure with a contaminated core layer and virgin outer layers, were developed with a known amount of a selected migrant in the inner layer. A phenomenological model based on a resistances-in-series was resolved through the regula falsi algorithm according to a routine that considers the income of the structural parameters of the system and experimental conditions in which migration testing was performed. The model’s accuracy in predicting migration was demonstrated successfully by comparing simulated results to experimental data. The computer program, developed as a total solution package for migration problems, can be applied not only to multilayer structures made with the same type of plastics but also to structures with different plastics.     

Overall migration from commercial coextruded food packaging multilayer films and plastics containers into official EU food simulants

The overall migration from a wide range of commercial five-layer coextruded packaging films into aqueous food simulants (distilled water, 3% aqueous acetic acid) and alternative fatty food simulant (iso-octane) was studied. The overall migration from commercial plastics cups (PS, HIPS, and PP) used for ice-cream or yogurt packaging into distilled water and 3% aqueous acetic acid was also studied. Test conditions for packaging material/food simulant contact and method of overall migration analysis were according to the EU directives and CEN-standards. The results showed that for all tested five-layer films and plastics (PS, HIPS, and PP) cups values of overall migration into aqueous simulants (0.11-0.79 mg/dm², 2.3-15.9 mg/l) and (<0.10-0.41 mg/dm², <0.80-3.1 mg/l) were significantly lower than the upper limit (10 mg/dm²) for overall migration from plastic packaging materials and articles into food and food simulants set by the EU Directive 90/128/EEC and their revisions. The overall migration values from five-layer materials into iso-octane were significantly higher (0.94-8.23 mg/dm², 18.8-164.7 mg/l) than the above values but are still lower than the upper limit for overall migration. Global migration values of five-layer films into aqueous food simulants seems to be independent of material thickness. In contrast, overall migration into iso-octane increases with film thickness.     

Antimicrobial nanoparticles and biodegradable polymer composites for active food packaging applications

The food industry faces numerous challenges to assure provision of tasty and convenient food that possesses extended shelf life and shows long-term high-quality preservation. Research and development of antimicrobial materials for food applications have provided active antibacterial packaging technologies that are able to meet these challenges. Furthermore, consumers expect and demand sustainable packaging materials that would reduce environmental problems associated with plastic waste. In this review, we discuss antimicrobial composite materials for active food packaging applications that combine highly efficient antibacterial nanoparticles (i.e., metal, metal oxide, mesoporous silica and graphene-based nanomaterials) with biodegradable and environmentally friendly green polymers (i.e., gelatin, alginate, cellulose, and chitosan) obtained from plants, bacteria, and animals. In addition, innovative syntheses and processing techniques used to obtain active and safe packaging are showcased. Implementation of such green active packaging can significantly reduce the risk of foodborne pathogen outbreaks, improve food safety and quality, and minimize product losses, while reducing waste and maintaining sustainability.     

Development of mono and multilayer antimicrobial food packaging materials for controlled release of potassium sorbate

In this study, cellulose acetate (CA) based mono and multilayer films including potassium sorbate (Psb) as an antimicrobial agent were prepared using dry phase inversion technique. To achieve appropriate controlled release of Psb, the structure of the films was changed by manipulating the film preparation conditions. In particular, the initial casting composition, wet casting thickness and drying temperature were varied. Results indicate that Psb release rate decreased as the CA content in the casting solution, the wet casting thickness and the drying temperature for both mono and multilayer films were increased. Compared to the results for the monolayer films, a significant decrease of Psb release rate through the multilayer films was recorded. Drying-induced crystallization was observed in the monolayer films. As a consequence of this, a fast initial release of Psb, controlled by Fickian diffusion, was followed by a slower release controlled by dissolution of Psb crystals. In multilayer films, no crystals were detected in the structure and the release rate was regulated only by diffusion of Psb through the film. The results suggest that the films prepared in this study can be used as food packaging materials for achieving controlled and extended release of Psb.     

造纸污泥干燥焚烧的生命周期评价

以造纸污泥为研究对象,应用生命周期评价方法对造纸污泥干燥焚烧的生命周期进行清单分析,以获得造纸污泥干燥焚烧处理方式的能耗及其对环境的影响,实现对全球变暖(GW)、大气酸化(AC)、水体富营养化(NE)以及烟尘和灰尘(SA)等环境影响的定量化,以获得污泥处理对环境影响的程度和趋势。