Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Migration of additives from polymers into food simulants: numerical solution of a mathematical model taking into account food and polymer interactions

The principle of a computing program describing precisely the migration of additives from a polymer into a food simulant is presented. As six parameters are used to fit the simulant sorption and additive extraction kinetics, the parameters have been determined by independent experiments. Owing to the complicated coupling between the liquid and additive diffusion processes, migration kinetics cannot be obtained by a mathematical resolution of kinetic equations, but they must be calculated by numerical analysis. The method is applied to a UV absorber in polypropylene migrating into glyceryl tripelargonate, a pure triglyceride, of which behaviour and average molecular weight are similar to official fatty food simulants. Properly designed experiments validate the model used to fit the migration kinetics. The possibility of erasing any parameters is also discussed.     

国内外食品包装材料安全管理状况及对策分析

为了解国际上食品包装材料的管理模式，为我国食品包装材料的安全管理提供借鉴，对美国、欧盟、日本、韩国等经济发达国家的食品包装材料管理模式进行了对比分析。从法规设置、管理机构、管理程序等角度进行比较，发达国家都建有比较完善的法规标准体系和高效清晰的管理程序，对包装材料的安全管理比较成熟。我国应尽快出台可操作性强的包装材料准入制度，对相关标准进行修订，并加强对包装材料安全评价和检测能力的建设。     

Polymer additive migration to foods - a direct comparison of experimental data and values calculated from migration models for high density polyethylene (HDPE)

To reduce the amount of compliance testing for food contact polymers the use of migration modelling has been proposed. This study was conducted to provide valid data for the independent evaluation of two such diffusion-based models using a range of different high density polyethylene (HDPE) polymers and plastics additives. Seventy-two experimental migration data have been obtained in triplicate and used to evaluate two Fickian-based migration models in the prediction of specific migration of four HDPE additives into olive oil. All tests were conducted using olive oil, representing the most severe case for fatty foods with test conditions of 2h at 70oC, 6h at 70oC, 10 days at 40oC representing short term exposures at high temperatures and room temperature storage. Predicted migration values were calculated by inserting the measured initial concentration of additive in the polymers (Cp,0) into the equations together with known variables such as additive molecular weight, temperature and exposure time. The results indicate that both models predict migration values into olive oil close to, or in excess of, the experimental results. The Piringer migration model, using the 'exact' calculations of the Migratest Lite program, gave an overestimation for 83% of the migration values generated in this study. The highest overestimation was 3.7 times the measured value. For all measurements, the predicted migration from the Migratest Lite program was greater than 50% of the observed value. The FDA model was found more accurately to predict migration in most situations but underestimated migration more frequently. Differences in the polymer specification had little effect on specific migration of the additives investigated.     

Development and validation of analytical methods for monomeric and oligomeric migrants from nylon 12 packaging materials

Analytical methods for the determination of laurolactam--the monomer of nylon 12--as well as the cyclic dimer and trimer were established. High performance liquid chromatography using ultraviolet (HPLC-UV) and mass spectrometric detection (HPLC-MS) were both found suitable to identify and quantify monomer, cyclic dimer and trimer well below the specific migration limit (SML) of laurolactam, being 5 mg/kg of food (simulant). Gas chromatography with flame ionisation detection (GC-FID) showed to be an appropriate method for the detection of only laurolactam in aqueous and fatty food simulants. Food simulants could be analysed directly by all three methods, or after a change of solvents. For olive oil, a method for sample clean-up by size-exclusion chromatography (SEC) was established.     

Determination of the mass transport properties of chemical additives in polypropylene material/simulated food system

The mass transport process (migration) of five additives from three different types of polypropylene (PP) films into selected food simulants was studied. The migration tests were carried out at different time-temperature conditions, and the concentration of additives in polymer matrix and food simulants were analysed by high-performance liquid chromatography (HPLC). With all data, the mass transport properties for migration kinetics (partition and diffusion coefficients) were determined. Results showed that the partition coefficient was affected significantly by the temperature and simulants’ properties, whereas little affected by the types of PP film and molecular weight of substance. The polarity, structure and shape of substances can also have an influence in their partition between the polymer matrix and food simulants. Additionally, comparison results between the experimental diffusion coefficients and the calculated values by Piringer model suggested that the current migration model with the default modelling parameters for PP does not describe realistically the diffusion coefficients of additives. The calculated diffusion coefficients were greater than the experimental values, as a consequence, the migration of chemical additives will be overestimated. For more realistic migration calculations, more accurate modelling parameters in Piringer model should be established and the effect of food on migration should be high interest in future work.     

Analysis of food packaging UV inks for chemicals with potential to migrate into food simulants

Ultraviolet (UV) inks are an alternative formulation system to the more usual paste or liquid inks (oils or solvents based) that dry mainly by evaporation or penetration into the printed substrate. Based on acrylic acid chemistry, UV inks dry (the exact term is 'curing') by the chemical process of photopolymerization. Their composition (acrylate monomers and oligomers together with photo-initiators) exposed to UV emission lamps on the printing press units enable the transformation of the freshly printed ink layer into a tack-free film. For UV inks intended for primary food packaging, special care has to be paid to potential migrating species like small photo-initiator molecules and acrylate monomers not cross-linked in the formed network. The paper presents chromatographic methods to ascertain the level of ink ingredients potentially available to migrate into food simulants (migration tests). GC/MS was employed to quantify the levels of photo-initiators or acrylic esters (acrylates).     

Polymer additive migration to foods-a direct comparison of experimental data and values calculated from migration models for polypropylene

To reduce the amount of compliance testing for food contact polymers the use of migration modelling is under discussion and being evaluated by an EU Commission funded project (Evaluation of Migration Models No. SMT4-CT98-7513). The work reported in this paper was exclusively funded by industry to provide data for the independent evaluation of a diffusion based model using eight different samples of polypropylene (PP) covering the range of polymers specification and five commonly used plastics additives. One hundred and fifty experimental migration data have been obtained in triplicate and used to evaluate a Fickian-based migration model in the prediction of specific migration of five additives into olive oil. All tests were conducted using olive oil, representing the most severe case for fatty foods, with test conditions of 2h at 121 ° C, 2h at 70 ° C and 10 days at 40 ° C, representing short term exposures at high temperatures and room temperature storage. Predicted migration values were calculated using the Piringer 'Migratest Lite' model by entering the measured initial concentration of additive in the polymers(C_p,0) in to the equations together with known variables such as additive molecular weight, temperature and exposure time. Where necessary the data generated in this study have been used to update the model. The results indicate the Piringer migration model, using the 'exact' calculations of the Migratest Lite program, predicted migration values into olive oil close to, or in excess of, the experimental results for > 97% of the migration values generated in this study. For all measurements, the predicted migration from the Migratest Lite program was greater than 70% of the observed value. This study has identified the possibility that random co-polymers of propylene and ethylene give higher migration than other grades of polypropylenes and could be treated as a separate case. However, further work on more samples of random co-polymers is required to confirm this finding.     

Searching for triangles: An extension to food & packaging

Two laboratory-based visual search experiments (Experiments 1 and 2) and an online survey (Experiment 3) were conducted in order to investigate the visual search for triangular foods. The results of Experiment 1 revealed that the visual search for a downward pointing triangular target was faster than when the same target pointed upward, regardless of whether the stimuli were simple geometric figures or photos of food. Experiment 2 replicated these results using images of both food and non-food packaging. Experiment 3 revealed that the same triangular stimuli were generally rated as less pleasant, less liked, and less familiar when they pointed downward than when they pointed upward. Taken together, these results therefore suggest that the cognitive processing of food images is influenced by incidental aspects of their visual appearance, and that such a pattern of results can also be extended to the case of food packaging.     

Influence of semi-solid fluid’s surface tension and rheological properties on the residues at packaging materials

Residues of food are unwanted in food processing and food packaging. Therefore different properties of high viscous food and their relevance to adhesion phenomena at packaging surfaces are investigated herein. The results may be utilised to reduce the amount of sticking content.In order to quantify the amount of remaining material a method of evaluation was designed using polysaccharides solutions and mixtures of highly viscous oils as model products. The surfaces tension and rheological properties were analyzed. The work of adhesion of each product-surface system was calculated from the respective contact angle data.It was found that the viscosity has a great influence on the amount of residues. For Newtonian liquids the influence is linear. For viscoelastic liquids there are other effects that cause fewer residues when the viscosity is increased. Furthermore, it seems that fewer residues remain when the dispersive part of the surface tension of the liquid is high. Aside from this the work of adhesion is a good measure to predict the amount of residue.     

Oxygen transfer in foods using oxygen luminescence sensors: Influence of oxygen partial pressure and food nature and composition

A rapid and easy to handle (on-line monitoring) method to achieve oxygen sorption kinetics was developed and tested on a large range of food products. Measurements were performed using luminescence sensors placed into of a thin layer of food material exposed to increasing oxygen contents in the atmosphere. From oxygen sorption kinetics diffusivity values could be calculated using a mathematical model based on Fick’s second law. A large range of model and real food were studied: water, agar gel, orange juice, mashed apple, mashed tomato, miglyol, olive oil and copra oil.     

我国常见包装食品营养成分标识的现状分析

为了解我国常见包装食品标签上标识值与检验值的符合情况并为标识数据的引用提供参考依据 ,调查了 10类 378种包装食品 ,共有 14 9种食品有营养成分标识 ,对这 14 9种标识的食品成分应用图标法或AOAC法进行一一对应的成分分析。同时参照GB 10 76 5～ 10 76 7— 1997《婴幼儿食品》中检验规则规定的允许误差范围判断 14 9种食品。成分标识值与检验值的总符合率为 6 7 1%,国内外品牌食品的符合率无统计学上的差异显著性。结果说明 ,大多数食品的标识值是可信的 ,可以为扩充国家食物成分数据来源提供有价值的参考资料     

Kinetic migration studies from packaging films into meat products

One of the main concerns regarding safety of food packaging is the possible migration of chemical substances (monomers and other starting substances, additives, residues) from food contact materials into foods. To evaluate the effect of the fat content and of the temperature of storage on the migration from plastics packaging films into meat products as an important class of foodstuffs, the kinetic mass transport of a model migrant (diphenylbutadiene) from low density polyethylene (LDPE) film in contact with different meat products was investigated. From the data, the diffusion coefficients were calculated for the applied test conditions, by use of a mathematical model. The results showed that migration increased with fat content and storage temperature. Analysis of migration data corresponding to minced pork meat containing different amounts of fat, stored for 10 days at 25°C, revealed an excellent relationship between migration level and fat content. This behaviour was also found for other types of meat products (chicken and pork neck). A simplifying mathematical model was applied to derive effective diffusion coefficients in the polymer which, however, do take kinetic effects in the meat also into account. In the case of pork meat contact, the effective diffusion coefficients derived from mathematical modelling were ten times higher for storage at 25°C (1.88×10(-9)cm(2)s(-1)) than for storage at 5°C (1.2×10(-10)cm(2)s(-1)).     

Oxygen permeation through an oil-encapsulating glassy food matrix studied by ESR line broadening using a nitroxyl spin probe

A non-invasive method based on the broadening of electron spin resonance (ESR) lines in the presence of oxygen (oximetry) has been developed to determine the rate of permeation of oxygen from head space into oil, encapsulated in a glassy matrix (a food model made from sucrose, maltodextrin and gelatine by freeze-drying). The lipophilic nitroxide 16-doxylstearic acid, 16-DSA, was used as a spin-probe, and it was found to be concentrated mainly in the oil phase in the glassy matrix. The concentrations of oxygen in the freshly made glasses were found to be similar to the concentration in atmospheric air, and the process of freeze-drying is apparently not able to remove oxygen before the glassy system solidifies. Storing the oil-encapsulating glasses under oxygen increased the oxygen concentration inside the matrices, and the rate of permeation was found to increase with temperature. A kinetic model for the oxygen permeation was established, based on the rate data obtained up to full saturation of the oil with oxygen below the glass transition temperature (T_g=65°C ), and on data for partial oxygen saturation above the glass transition temperature. The kinetic model includes a temperature independent master curve and allows for structural heterogeneity. The energy of activation for oxygen permeation was found to be 74±6 kJ/mol for the glassy matrix, and the large value is in favour of the molecular model for oxygen diffusion rather than the free volume model, and accords with the zeroth-order kinetics for oxidation of lipids encapsulated in a glassy matrix, which has previously been observed to be associated with oxygen permeation as the rate-determining step.     

A study on the migration of organic pollutants from recycled paperboard packaging materials to solid food matrices

Paper and board are widely used as food packaging materials, mainly for disposable products. As public interest in conservation of natural resources has accelerated in the past several years, the use of recycled paper and board has increased. Recycled fiber materials can be used in certain limits as food contact materials. The safety of recycled fiber-based materials for food contact applications is largely dictated by the ability of post-consumer contaminants to be absorbed into recycled materials and later released by the packaging material and trapped on the food. The present work was undertaken with the aim of investigating the physicochemical behavior of selected model contaminants on paper and board, in contact with foodstuffs thus producing a fundamental set of data about their mobility from recycled paper and board into foods. More specifically, the kinetics of migration of selected model contaminants (surrogates) from contaminated recycled paper packaging samples into dry foodstuffs with different fat content was studied using a method based on solvent extraction and GC-FID quantification. Results showed the ability of selected contaminants of various types and various volatilities to potentially transfer to dry foods. The proportion of substances migrated to food was strongly dependent on the nature of the paper samples, fat content of the food, chemical nature and volatility of the migrant. The highest level of migration of organic pollutants was observed for the substrate with the highest fat content. Furthermore, it is shown that contact time and temperature have a significant effect on migration of model contaminants into foods.     

Stability testing of selected plastics additives for food contact in EU aqueous, fatty and alternative simulants

Within the framework of the AIR3-CT94-2360 EUproject, the stability of three plastics additives in three EU aqueous and fatty food simulants and in two alternative simulants was studied under various timetemperature conditions. The additives tested were bis(2-ethylhexyl) adipate (DEHA), bis(2-ethylhexyl) phthalate (DEHP) and octadecyl 3-(3,5-di- tert -butyl4-hydroxyphenyl) propionate (Irganox 1076). The various test conditions included exposures of 10 days at 40 o C, 1h at reflux temperature for all aqueous simulants, 10 days at 40 o C and 1h 175 o C for the olive oil and 2 days at 20 o C and 3h at 60 o C for the isooctane simulant. Following the exposure, the additive samples were extracted from aqueous simulants with hexane. A sonication step was necessary to ensure maximum extraction of control samples. In the case of the isooctane simulant, the samples were analysed directly from the simulant. The oil samples were extracted by acetonitrile. The extracts of samples exposed to various heat conditions as well as unexposed spiked controls and blanks were analysed by gas chromatography (GC) on a non-polar (5% -phenyl)-methylpolysiloxane capillary column with high temperature capabilities. The results showed that DEHA, DEHP and Irganox 1076 were stable at 40 o C and at reflux temperature in ethanolic or acidic aqueous simulants. The various additives were also stable in the organic isooctane simulant as well as in the fatty simulant olive oil. Studies on the stability of such additives used in food packaging are designed for regulatory purposes as an aid to decide whether the legislation should regulate limits for plasticizers based on a quantity in the food packaging itself or based on an ingested dose by the consumer.     

酸水解冬虫夏草胞外多糖的分子质量变化及动力学研究

以冬虫夏草胞外多糖为研究对象,通过凝胶渗透色谱分析酸水解多糖的分子质量、分子质量降解率(MWDR)和多分散指数(MW/Mn)的变化规律,并在此基础上探讨酸水解动力学。结果表明：酸水解可得到高分子质量和低分子质量两个多糖组分,高分子质量多糖组分的含量、分子质量和MW/Mn均随酸解时间的增加而减小,而MWDR呈线性增加趋势。低分子质量多糖组分含量随酸水解时间的增加而增加,分子质量基本维持在3.0kD;MWDR在0.5h内呈线性增加趋势,大于0.5h后基本维持在0.25。胞外多糖的酸水解模式为中心链断裂,符合假一级反应动力学方程,反应速率常数为3.24×10-2min-1,远小于随机链断裂的反应速率常数。     

Evaluating the migration of ingredients from active packaging and development of dedicated methods: a study of two iron-based oxygen absorbers

The behaviour of two commercial oxygen-scavenging products with respect to migration of active ingredients into foodstuffs was investigated. Migrants were identified, and by using appropriate analytical methods, migration was determined in a variety of liquid, solid or gelled food simulants and foods. Simulants were chosen to cover a range of water activities and viscosities. Foods and the gelled food simulant agar were packed with and without vacuum, and with the oxygen scavenger in various locations relative to the packed food. The main migrants, as identified by X-ray fluorescence spectrometry, infrared spectroscopy and scanning electron microscopy with energy-dispersive spectrometry were Na + and Cl - in non-acidic aqueous simulants, and Na + , Cl - and Fe 2+ in 3% acetic acid. Migration into aqueous simulants exceeded the current European Union limit for total migration from plastic materials (assumed to be currently applicable to these systems) and was probably excessive by any reasonable standard. However, neither oxygen scavenger appeared to release significant quantities of migrants into solid foods when the scavenger was properly located in the package and the packing process does not favour the contents becoming wet by water released from the food.     

国内外新型食品包装材料审批管理模式分析

目的为我国新型食品包装材料审批管理体系提供借鉴,加快我国审批管理系统化的进程。方法介绍我国、美国、欧盟、加拿大、澳新、日本新型食品包装材料的审批管理在管理部门、审批方式、资料要求和发布形式方面的规定,比较各管理模式之间的异同,并分析相关性和显著特点,及其对我国管理的启示。结果各国在管理部门、审批方式、资料要求和发布形式4个方面有其显著的特点,对我国管理模式有很多值得借鉴的地方。结论各个发达国家基本建立了适合于本国的管理模式,在我国新型食品包装材料审批管理模式形成的初级阶段,应充分借鉴其他发达国家的先进经验,逐步形成适合我国国情的管理体系。     

Fresh from the tree: Implied motion improves food evaluation

The current research explores whether the often-used depiction of foods in motion both on packaging and in marketing campaigns helps improve consumer judgments of food products. In two studies, we show that depictions of food with implied motion lead to enhanced evaluations of both freshness and appeal. This occurs even when motion is merely implied, rather than actual. These findings shed light on the common practice of showing motion in food advertising and in food packaging design. We argue that this phenomenon may relate to an overextension of a primitive link between motion and freshness. This feature can be used to help promote healthier food choices and consumption by increasing their appeal via implied motion.