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Article
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Total elimination of oxygen (O2) in modified atmosphere packaging of bakery products is difficult to achieve. Because of the typical porous texture of the packaging, air can be retained inside. The effect of O2 absorbers alone or in combination with modified atmosphere on Eurotium amstelodami, E. herbariorum, E. repens, and E. rubrum growth was investigated. Cakes of 0.80 to 0.90 water activity (aw) were packaged with different atmospheres (air, 100% N2; 70% N2:30% CO2) and O2 absorbers of 2 different absorption capacities. The use of absorbers with a suitable absorption capacity led to a significant increase of cakes with mold-free shelf life, regardless of aw and pH level, at 25 °C.
Article
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The objective of this study was to investigate the quality properties of sliced and modified atmosphere-packaged salami during refrigerated storage. Salami was sliced and packaged under air and three modified atmosphere packaging (MAP) compositions (100% N2; 50% CO2, 50% N2; 5% O2, 25% CO2, 70% N2) in polypropylene trays sealed with polyethylene terepthalate/polyvinylidene chloride/oriented polypropylene. Headspace oxygen and carbon dioxide (%), physical (color and texture), chemical (pH) and sensory properties were analyzed for 20 days at 4C. The results showed that CO2 concentration (%) decreased after 5 days of storage for MAP applications with high CO2, which was attributed to the solubility of CO2 in the salami. The pH did not significantly change during storage at all applications (P > 0.05). While L values increased, a and b values decreased during storage. The MAP applications with no oxygen received higher panelist scores and provided better quality characteristics than air and 5% O2, 25% CO2, 70% N2 for 15 days. Nowadays, consumers demand for safe, nutritious and ready-to-eat/use food products. The use of modified atmosphere packaging (MAP) for ready-to-eat/use meat products has considerably increased in recent years. Salami that are sliced and packaged in smaller portions could attract consumers interested in individual portions at supermarkets. Although optimization of gas composition is critical to ensure the product's quality and safety, only a few studies have focused on the preservation of meat products like salami. Atmospheres with no oxygen could be used for MAP of sliced salami as color, textural and sensory properties were preserved better than atmospheres with oxygen. Previous studies stated that vacuum packaging did not inhibit microbial growth; however, MAP with CO2 was found effective on microorganisms due to its bacteriostatic effect. Therefore, MAP packaging of sliced salami would be a better option than vacuum packaging.
Article
Full-text available
The barrier solutions presently available on the market all have their drawbacks, e.g. cost, water‐sensitivity, opacity or perceived environmental bad‐will. At the same time there is a trend to use more plastic‐based packaging materials for different applications, e.g. as replacements for metal and glass containers. This situation has stimulated the industry to provide new, more efficient barrier solutions. The innovations go along five major lines: (a) thin, transparent vacuum‐deposited coatings; (b) new barrier polymers as discrete layers; (c) blends of barrier polymers and standard polymers; (d) organic barrier coatings; and (e) nanocomposite materials. This paper provides a comprehensive review of the different approaches, outlining the principle behind each barrier technology, its performance, its potential and the companies developing and producing the materials. Copyright © 2003 John Wiley & Sons, Ltd.
Article
An experimental investigation was carried out in order to appraise the evolution of volatile compounds in ripened sausages during vacuum storage, by SPME-GC/ MS technique. The obtained results pointed out the influence of vacuum storage on the evolution of volatile compounds. In particular, the substances originated from carbohydrate fermentation showed an increase during time, while those derived from spices decreased. Volatile compounds derived from the oxidation of lipids, that are among the chiefly responsible of sensorial properties of meat products, were detected in low percentages. Furthermore, during storage they showed a significant increase starting from two months of storage.
Article
A very attractive solution in food packaging technology is the functionalization of packaging materials by incorporating an active phase into polymeric matrices. Nowadays, the applications of active substances into flexible packaging are very limited due to difficulties in realizing performing films by common manufactory processes. This work is focused on the production and characterization of monolayer poly(ethylene terephtalate) (PET) active films at different concentrations of an oxygen scavenger by cast extrusion process. Rheological, thermal, morphological analyses and oxygen absorption measurements were carried out on the produced samples to investigate the structure of active PET films and to determine their scavenging properties. Overall migration analyses were performed on active films to asses their safety in use with foodstuff, and finally the produced films were used to package fresh banana slices for evaluating their capability in quality foods preservation. Copyright
Article
Absorption kinetics of three different forms of the same iron-based oxygen scavenger were studied. Oxygen scavengers were used as pellet, sheet, and film materials. Two scavenger concentrations were used for sheet and film forms. Scavenger samples were analyzed at 75 or 100% relative humidities and stored at 5, 15, and 25°C. Oxygen concentration in the headspace was measured as a function of time. Absorption kinetics was best described by the Chapman-Richards empirical growth model rather than by a first-order reaction. Arrhenius behavior was observed for variations in the final absorption rate with temperature. Absorption capacities, final absorption rates, and activation energies were evaluated and discussed. Scavenger concentration, relative humidity, and temperature effects on kinetic parameters were studied for each experimental condition. Temperature was the most important factor that affected kinetic parameters. At the relative humidity levels studied, any important effect on kinetic parameters was not observed, except on absorption capacities.
Article
A rapid, dependable method of on-line package inspection will allow wider implementation of energy-and material-ef®cient retortable pouches and trays, by reducing inspection costs. To evaluate high-frequency ultrasonic imaging as a sensing method, the 17Á3 MHz ultrasonic pulse-echo Backscattered Amplitude Integral (BAI) method was used to visualize and evaluate major defects (channels and product inclusions, which compromise the seal integrity and must be reliably inspected) in the seal area of ¯exible food packages. The focus of this study was to evaluate the image contrast, denoted DBAI, for various packaging materials, defect types and sizes. Channel (6±100 mm in diameter) and inclusion defects (strands of mouse tail tendons, 20±150 mm) were created in the seal area of all-plastic and foil-containing packaging ®lms. It has been shown that there is a direct relationship between the defect size and DBAI value, and that different defect types and packaging materials have a signi®cant impact on the DBAI value. The utility of DBAI for detecting defects makes it a useful and reliable sensing method for package inspection.
Article
One of the most important processes in the food and pharmaceutical industries is the leakage detection of sealed packages to prevent pollution by bacteria. A high frequency, high voltage method is used as a highly reputed method for high accuracy inspection of ampoules and sealed food packages for pinholes. This paper outlines a pinhole inspection machine. © 1997 John Wiley & Sons, Ltd.
Article
While oxygen scavengers sandwiched between barrier resins such as PET are targeted for making super barriers to reduce ingress oxygen, oxygen scavengers used in flexible packages or in caps and closures are designed with oxygen permeable food contact/seal layer to allow fast removal of head space oxygen. Unfortunately, such permeable food contact layers are inadequate in keeping organic oxidation by-products from migrating into packaged food and drinks. Therefore strong off taste and off odors are often detected in food packaged in commercial oxygen scavenging polymers based on MXD 6 nylon and other conventional unsaturated polymers. This paper presents a proprietary, practical and economical break through in oxygen scavenging technology to meet both these highly demanding sensory requirements, as well as the stringent FDA regulation of no detectable (< 50 PPB EDI) migrating polymer byproducts in extraction studies. Chevron 's proprietary oxygen scavenging system was petitioned under Food Contact Notification (FCN) with the FDA in February of 2000 with an anticipated approval in June 2000. Steps to ensure EU food law compliance and chemical registration are also underway. This important non-fragmental active oxygen scavenger concept could be incorporated to make "super oxygen barriers" out of traditional passive barriers such as EVOH and other well known flexible and rigid packaging polymers. Potential impact of this technology to future flexible and rigid packaging design will be discussed.
Article
An evaluated compilation of equilibrium relative humidities in air vs. temperature from pure phase to approximately 10**5 pascal (1 atm) in pressure is presented for 28 binary saturated aqueous solutions. The relative humidities of the solutions range from about 3 to 98%. Using a data base from 21 separate investigations comprising 1106 individual measurements, fits were made by the method of least squares to regular polynomial equations with two through four coefficients. Equations and tables are presented along with the estimated uncertainties in the correlated results.
Article
The aim of this paper is to provide a framework, whereby gas permeation rates through plastic packaging walls, and hence, food shelf life may be estimated. Although the approach is quite general, specific attention is given to the case of liquid-filled polyethylene terephthalate (PET) bottles with oxygen as the permeating gas. Two situations are considered: when the walls simply provide a passive resistance to the flux (as is the case for standard PET or PET blended with some other low permeability material) and when an active gas scavenger is incorporated within the boundary material. For the passive wall, permeability data relative to oxygen have been collected from literature sources and also measured using specific oxygen transmission rate experiments. For the active walls, scavenger kinetic constants were estimated from data obtained using test bottles prepared with varying scavenger concentrations. Numerical predictions in both cases have been verified by comparison with data on gas concentration in water-filled bottles maintained under controlled conditions for periods of up to 6 months. Copyright
Article
The oxygen (O2) absorption kinetics of six commercial O2 scavengers were studied. The scavengers were placed in bags which were filled with 240 mL of air, 4.5 L N2 + 15 mL of air, or 3.5 L CO2 + 9 mL of air. The O2 concentration in each bag was measured at hourly intervals for 8 h. The effects of variability among individual scavengers, initial O2 concentrations of 20% or 500 ppm (0.05%), temperatures of 25, 12, 2 or −1.5 °C, and scavenger capacity on the O2 absorption rate were determined. In addition, the effect of placing scavengers within over-wrapped trays within bags, was examined. Rates of O2 absorption varied by factors of up to 2 between individual O2 scavengers of the same type, but rates of absorption by groups of four scavengers of the same type were similar. Low temperatures gave longer O2 half-life when compared with those at higher temperatures, e.g. O2 half-lives of 7.1 and 1.0 h at −1.5 and 25 °C, respectively, were obtained for one scavenger type. Shorter O2 half-lives were obtained in air than in N2 atmospheres at the same temperature, e.g. O2 half-lives of 1.0 and 3.3 h in air and N2 at 25 °C, respectively, were obtained for one scavenger type. The O2 absorption reactions were of first order for both high and low initial O2 concentrations. However, O2 concentration was the primary limiting factor for O2 absorption in atmospheres having O2 concentration of 500 ppm because of the dominance of diffusion. Scavengers, when placed within over-wrapped trays within bags had up to 12 times longer O2 half-lives, indicating that the O2 permeable film acts as an O2 barrier when pack atmosphere has low O2 concentrations. To obtain consistent and reproducible results, it is recommended that multiple scavengers be used in a packaging system. The appropriate number should be based on scavenger type, desired O2 absorption rate, storage temperature, and pack atmosphere (air/N2/CO2).
Article
Steady- and unsteady-state gas permeation rates through packaging walls containing active (scavenger) materials are determined as functions of the system's physical parameters and the scavenger load. With the simplifying assumptions of constant scavenger concentration and first-order reaction kinetics, steady-state analysis shows that there is a minimum quantity of scavenger that must be added to the packaging wall if any reduction of gas permeation is to be achieved. Unsteady-state studies have established the dependence of the time needed to reach stationary behaviour on the system's physical parameters. Copyright © 2007 John Wiley & Sons, Ltd.
Article
Summary The effect of O2 scavengers on the colour stability of beef in retail overwrap trays within a modified atmosphere mother pack (CO2/N2) was assessed. Steaks from six muscles, namely Longissimus dorsi, Psoas major, Semimembranosus, Gluteus medius, Semitendinosus and Biceps femoris were examined. After storage for 2, 4 or 6 weeks mother packs were opened and steak colour was monitored during 96 h of retail display. Redness of all muscles stored with O2 scavengers was superior to that of steaks stored without O2 scavengers at all storage times. Hue angle results indicated some metmyoglobin formation in all muscles during storage. Comparisons were made between steaks stored with O2 scavengers and fresh steaks. Shelf-life values were calculated using the reflectance difference method (R630–R580). O2 scavengers did not affect weight loss from the stored steaks.
Article
The shelf life of extra virgin olive oil (EVOO) and sunflower oil (SO) bottled in containers with different levels of oxygen scavenger (OS) and stored at room temperature under diffuse lighting conditions for 6 months has been evaluated. Four packaging materials were tested: glass, polyethyleneterephthalate (PET), PET including 1% of OS (PET 1%) and PET including 5% of OS (PET 5%). Free acidity, peroxide value (PV), spectrophotometric indices (K232, K270, ΔK), antioxidant (biophenols and tocopherols) content, pigment (chlorophylls and carotenoids) change and the amount of oxygen dissolved in the oil were monitored during storage. A significant influence of the packaging material on the quality decay was not found. The differences in the shelf life observed between oils bottled in PET and oils bottled in glass are attributable to a difference in the initial content of dissolved oxygen in the oils. The study showed the usefulness of monitoring changes in dissolved oxygen level, antioxidant (phenols and tocopherols) and pigment (chlorophyll and carotenoids) profiles during oil storage. The change of these compounds could in fact supply important information on the oxidation processes that occur in bottled oils and on the effectiveness of the material employed in oil packaging. Copyright © 2007 John Wiley & Sons, Ltd.
Article
Color and nitrosoheme pigment stabilities of dry salami packaged in films differing in oxygen transmission rate (OTR) were studied. Product exposed to light for 8 wk had greater (p < 0.05) retention of redness properties (Judd-Hunter +a coordinates, a/b ratios, hue angles (Q and saturation (S) index values) and greater (p < 0.05) nitrosoheme pigment stability as the OTR of the packaging film decreased from 90 cc 02/m2/24 hr to ≤11 cc 02/m2/24hr. Redness properties and percent nitrosoheme pigment progressively decreased (P < 0.05) during light exposure. Significant redness fading occurred in light-exposed product when compared to dark-stored product. Oxygen transmission to the dry salami surface was a major factor in color loss, primarily if light energy was also present.
Article
Dry fermented salami was prepared from formulations in which 0, 15 and 30% levels of both mechanically processed beef product (MPBP) and structured soy protein fiber (SSPF) were incorporated. A 10-member trained sensory panel for flavor found that the frequency of undesirable flavors was highest for salami with 15% SSPF-pH 6.2-0% MPBP and lowest for 0% SSPF-15% MPBP and 0% SSPF-30% MPBP. A second l0-member trained panel found that the salami with 30% SSPF-0% MPBP was lightest in color, while a 116-member untrained panel found this formulation was undesirable in flavor, tenderness, and overall desirability. Instron and Hunter Color Difference measurements reflected a toughening and lightening of color, respectively, for the 30% SSPF-0% MPBP salami in contrast to those treatments made with MPBP. Data from objective measurements (Instron and Hunter Color Difference Meter) were combined for all treatments and showed that salami increased in firmness and darkened with drying time. Both the trained and untrained sensory panels rated salami manufactured with 15 or 30% MPBP as generally comparable to the control salami.
Article
Many volatile compounds can be identified in unprinted paperboard by means of steam distillation in combination with capillary gas chromatography, mass spectrometry and olfactometry. Paperboards produced with recycled material exhibit additional volatiles which partly contribute to off-odours. Using sniffing techniques, benzaldehyde, acetophenone, 1-octen-3-ol, 1-octen-3-one, 2-nonenal, methylguajacol, butanoic and 3-methyl butanoic acid were identified as the most odorous volatiles. The aromatic substances mainly exude from inks and printing solvents in waste materials used for paperboard manufacturing. During storage under controlled conditions, the microbial load of paperboard decreased slightly, and no odorous metabolic products were generated. Copyright © 2001 John Wiley & Sons, Ltd.
Article
The feasibility of using a non-destructive ultrasonic technique for detecting defective seals was studied. It was found that ultrasonic velocity could be used to distinguish defective seals (containing wrinkles, voids, minute amounts of carrot, beef pieces, moisture or bentonite as contaminants) from a good seal. Also, there was a systematic correlation between ultrasonic velocity and the levels of contaminant.
Article
The current trends in packaging technology are focusing on the development of functional materials that interact with the environment and with the food, playing an effective role in the preservation of quality. In particular, the so-called active packaging technologies were developed as a response to the market needs for minimally treated foodstuffs, in order to preserve their freshness and flavours by regulating the gas composition of the packaging headspace through active scavengers. One of the most promising approaches for this technology is the incorporation of active scavengers into a polymeric matrix. Nevertheless, the design and the production of a functional and efficient active flexible package can be difficult to realize because of the complexity of the system. This work was thus focused on the production and the analysis of monolayer polyester films containing an oxygen scavenger. The active film was obtained by adding the active phase into a polyethylene terephthalate matrix during the extrusion process. The barrier properties of the films were investigated by means of conventional permeability measurement, to assess their activity with respect to oxygen. Additionally, the oxygen absorption of the active samples was analysed by an innovative oxygen meter system, in order to determine their scavenging capacity and reaction kinetics. The analysis of colour was carried out on packaged fresh apple slices, to verify if the active films produced were able to limit the oxidation processes on a sensitive food. Finally, the optical properties of the samples were investigated through haze measurements. Copyright © 2007 John Wiley & Sons, Ltd.
Article
The objective of this study was to apply the finite element method (FEM) to modelling the simultaneous oxygen diffusion and chemical reaction in a packaged liquid food. Cylindrical high-density polyethylene (HDPE) packages, top and bottom insulated, were designed to contain apple juice or water containing vitamin C. Oxygen consumption was monitored by a micro-oxygen electrode. A first-order chemical reaction and its reaction rate constant 7.3 ± 10-3/min (in terms of O2 consumption) was determined in apple juice with added vitamin C. The simultaneous permeation-diffusion reaction process was modelled by finite element block types developed by Swanson Analysis Systems. Inc. Houston, PA (Engineering Analysis Systems User's and Theoretical Manuals). Results indicate that the model generates acceptable predictions for a cylindrical, permeable package and a semi-infinite system (oxygen-saturated liquid surface).
Chapter
Introduction: Barrier Function of Polymer-Based PackagingPermeation Through Polymeric Materials Substance Transport Through Monolayer Polymer FilmsSubstance Transport Through Multilayer Polymer Films (Laminates)Units for Different ParametersSubstance Transport Through Single and Multilayer Polymer Substrates Combined with One Inorganic Barrier Layer Numerical ModelingSimplification: Barrier Improvement FactorMultilayer Polymer Substrates Combined with One Inorganic LayerPolymer Substrates Combined with an Inorganic Barrier Layer and Other Polymer Layers on Top of the Inorganic LayerTemperature Behavior of the Structures Shown AboveSubstance Transport Through Thin Polymer Layers Having Inorganic Layers on Both SidesSubstance Transport Through Polymers Filled with ParticlesExperimental Findings: Polymer Films and One Inorganic Barrier Layer Structures and Defects in Inorganic Barrier Layers on Polymer SubstratesComparison of Model Calculations and Experimental Results for Combinations of Polymer Films and One Inorganic Barrier LayerApparent Additional Transport Mechanisms for Water VaporProperties of Systems with at least One Inorganic Layer Embedded Between to Polymer Layers or FilmsExperimental Findings: Combinations of Polymer Films and More Than One Inorganic Barrier LayerExperimental Findings: Polymers Filled with Platelet-Shaped ParticlesExperimental Findings: Permeation of Flavors Through Mono- and Multilayer Films and Combinations with Inorganic Barrier LayersConclusions References Substance Transport Through Monolayer Polymer FilmsSubstance Transport Through Multilayer Polymer Films (Laminates)Units for Different Parameters Numerical ModelingSimplification: Barrier Improvement FactorMultilayer Polymer Substrates Combined with One Inorganic LayerPolymer Substrates Combined with an Inorganic Barrier Layer and Other Polymer Layers on Top of the Inorganic LayerTemperature Behavior of the Structures Shown AboveSubstance Transport Through Thin Polymer Layers Having Inorganic Layers on Both Sides Structures and Defects in Inorganic Barrier Layers on Polymer SubstratesComparison of Model Calculations and Experimental Results for Combinations of Polymer Films and One Inorganic Barrier LayerApparent Additional Transport Mechanisms for Water VaporProperties of Systems with at least One Inorganic Layer Embedded Between to Polymer Layers or Films
Article
This study investigated the ability of an online pressure differential leak detector to assess the quality of seals in 355 ml fiber-based brick-type composite packages. Results of these tests showed that: (1) the minimum leak size detection was 25 μm in diameter; (2) the leak tester was capable of detecting longitudinal seals made with sub-optimum sealing conditions; and (3) headspace analysis showed that the leak tester will not produce false positives results if the headspace measurement is less than 3.5 cm. The leak detector did not significantly weaken the seals of good packages. The results of this study can be used to verify the efficiency of similar non-destructive leak testers in a commercial environment and to develop a time saving alternative method for sealing quality analyses of brick-type packages.
Article
This study investigated the effectiveness of ultrasonic imaging for non-destructive assessment of seal strength in 335 ml polymeric trays. In the first part of this study, the experimental procedures involved filling sample trays with beef enchilada, then sealing at temperatures of 170–260°C for 5 s at 3 bar. Ultrasonic measurements were conducted using an immersion technique in pulse/echo mode. The captured signal amplitudes of the reflections from the samples were digitized and analysed to construct high-resolution C-scan ultrasonic images of the seals. The acquired data were statistically analysed for each sample and used as a basis for comparison with the seal (peel) strength, measured as the energy at break. The energy at break was obtained from destructive peel strength analysis, performed using a tensile testing frame. In the second part of this study, ultrasonic imaging was used to predict the performance of the heat sealer used to fabricate the test trays by comparing the seal quality of each of the four quadrants of the samples trays. This study also investigated the minimum channel leak size that could be detected using this ultrasound system. The results of the peel strength analyses showed that a direct correlation exists between seal strength and sealing temperature (170–227°C). Results of the ultrasonic imaging showed that the statistical scatter in the signal amplitude decreased as the sealing temperature increased. This reduction in the scatter of the signal amplitudes indicated a trend of increasing uniformity in the fusion of the two seal faces. Between 170°C and 193°C, sharp changes in the scatter were observed; however, little change was noted for sealing temperatures greater than 193°C, indicating that 204°C could be a minimum recommended sealing temperature. To confirm this result, a drop test analysis was performed on trays filled with beef enchilada and sealed at temperatures of 170–260°C for 5 s at 3 bar. Results of this drop test confirmed that 204°C was the minimum critical sealing temperature. Based on these results, ultrasonic imaging appeared to offer a promising non-destructive method for the prediction of seal quality in polymeric trays, sealing equipment monitoring and identification of channel leaks ⩾20 µm in diameter, and is comparable with the more established destructive peel strength analytical method. Copyright © 2003 John Wiley & Sons, Ltd.
Article
ABSTRACTA mathematical model was developed to study the influence of film perforations on O2 concentration and relative humidity in the atmosphere in a package containing fresh fruits. The model included equations describing fruit respiration and transpiration as well as permeation of oxygen and water vapor through the perforated film. Closed-system experiments with mango fruit revealed a linear dependence of respiration rate on O2 concentration. The model allowed analytical computation of the time course of in-package O2 concentration and relative humidity, and the results were in good agreement with experimentally measured values. Perforations had a much more pronounced effect on O2 concentration than on relative humidity. The model enabled practical predictions for designing modified-atmosphere packaging.
Article
Oxygen scavengers are commonly used in packaged foods in Japan and much less so in other developed countries, in spite of the advantages that they offer in maintaining quality and extending shelf-life. The reason stems from the additional cost involved, and even more so because of the lack of sufficient technical information on their performance and the lack of understanding of how to apply them effectively. In the present study the performance of iron-based oxygen-scavenging sachets was evaluated. It was found that the actual scavenging capacity is much higher than the ‘nominal’ capacity provided by the manufacturers. Also, a significant distribution in the oxygen absorption capacity exists, even in the same scavenger type. The rate of oxygen scavenging was found to depend on the scavenger type and capacity. It was also found that in an atmosphere containing CO2 (as in MAP applications) the iron-based oxygen scavengers also absorb CO2. Copyright © 2004 John Wiley & Sons, Ltd.
Article
Absorption kinetics of two commercial O2 and CO2 scavengers commonly used in active modified atmosphere packaging (MAP), were studied. Individual scavenger sachets were placed in polyvinylidene chloride pouches filled with air or modified atmosphere at 0% or 100% relative humidity and at 5, 20 and 35 °C. The headspace gas composition was measured as a function of time. Absorption kinetics were described by a first-order reaction with an Arrhenius type behaviour. The absorption capacity, absorption rate constant, energy of activation, Arrhenius constant and variation of all these parameters were evaluated and discussed. Significant “parasite” CO2 absorption was observed for O2 scavengers. This study also underlined the need to take into account the important variation of absorption rate constant (about 20%) among individual gas scavengers and the temperature effect for reliable evaluation of the gas kinetics when using O2 or CO2 scavengers in an expected and secure way.
Article
Gas diffusion properties of transparent thin film coatings have been under investigation by a number of workers for application in food and medical packaging. Work on the oxygen permeation properties of high barrier thin film coatings is reviewed, with emphasis on the coating thickness dependence of the oxygen permeation rate. Comparison of the coating thickness dependence of the oxygen permeation properties of evaporated, sputtered and plasma-deposited transparent oxide and organic coatings suggests that the reduction in permeation due to the coatings is limited by transport through coating defects (e.g. pinholes, grain boundaries or microcracks). The usefulness of such measurements as a probe of coating microstructure is assessed by reviewing structural and permeation investigations of metallized coatings on polymers.
Article
The effect of leaking on the quality and leak detection in modified atmosphere packages of chilled minced meat steaks were studied. Leaks of various sizes were made experimentally with tungsten thread and packages were stored for 5 weeks at +5°C or +10°C. The results indicated that the microbial counts in minced meat steaks increased with increasing leak size at the storage temperature of +5°C, but not at +10°C, where temperature became a more important factor for microbial growth than the rate of the leakage studied. At both temperatures, the sensory quality of minced meat steaks was better maintained in packages with capillary leaks the diameter and length of which were 69 and 3000 μm and 169 μm and 3000 μm, respectively, than in intact packages or in packages with capillary or pinhole leaks the diameter and length of which were 270 and 3000 μm or 65 and 70 μm, respectively. The packages stored at +10°C contained a coloured redox indicator, which was very useful and reliable in the monitoring of those leaking packages which were poor in quality.
Article
Barrier films deposited on flexible substrates are indispensable for a lot of applications. These are, for example, flexible displays based on LCD or OLED devices, flexible solar modules, materials for thermal insulation (e.g., vacuum insulated panels) or food packaging. The abovementioned applications already reveal very different requirements of barrier properties. Barrier films for food packaging for example can be produced with a single evaporated film, whereas the encapsulation of LCDs or OLED devices on flexible substrates is more sophisticated. In general, the approach of a complex multilayer system is used to fulfil the requirements for these ultrabarrier applications. In addition to their barrier properties, these multilayer systems also have to exhibit high transparency for many applications. In this case, a layer system can be used, that is based on sputtered Al2O3 layers, which are separated by different types of intermediate smoothing layers. This paper describes the concept and development of the Fraunhofer PolO alliance (www.polo.fhg.de) with regard to ultrabarriers for different applications. The barrier improvement of sputtered Al2O3 films deposited in a roll to roll process is analyzed. Further, the lacquering of inorganic organic hybrid polymers (Ormocers®) is described and synergetic effects from the use of the hybrid polymers in combination with sputtered Al2O3 films are discussed. Finally the assembly of an all flexible OLED test device is described, showing the suitability of complex multilayer systems for ultrabarrier applications.
Article
Rates of O(2) absorption from air were determined for a type of commercial O(2) scavenger that is formulated for rapid O(2) absorption at chiller temperatures. Rates of O(2) absorption from N(2) atmospheres containing 600 ppm O(2) were determined for trays that each contained 350 g of ground beef. Packs with controlled atmospheres of N(2) that contained ground beef and O(2) scavengers were prepared, to determine the conditions under which the scavengers could prevent the transient discolouration of the meat which arises from its reaction with the residual O(2) initially present in pack atmospheres. The rates of O(2) absorption by individual scavengers varied from the average by ±50%. The rate of O(2) absorption declined with decreasing oxygen concentration, from an average value per scavenger of about 12 ml h(-1) when O(2) concentrations were between 20 and 10%. At O(2) concentrations <1% (10,000 ppm) the rate of O(2) absorption was directly proportioned to the O(2) concentration so that the O(2) concentration in an atmosphere in a gas-impermeable pouch declined exponentially with time. The absorption of O(2) by ground beef was similarly dependent on the O(2) concentration. At 2 °C, the transient discolouration of beef in atmospheres initially containing about 50 ppm O(2) was prevented by the presence of 17.5 scavengers per l of atmosphere. At -15 °C, discolouration was prevented by 5 scavengers per l. The findings indicate that the O(2) concentration in pack atmospheres has to be reduced below 10 ppm within 30 min at 2 °C, or 2 h at -1.5 °C if ground beef is not to transiently discolour. It is unlikely that the required rates of O(2) absorption could be obtained economically with currently available, commercial O(2) scavengers.
Shelf life studies of foods and beverages: chemical, biological, physical, and nutritional aspects. Developments in food science
  • G Charalambous
Charalambous G. Shelf life studies of foods and beverages: chemical, biological, physical, and nutritional aspects. Developments in food science. Elsevier: Amsterdam, New York, 1993.
Oxygen scavenging composition. WO/1996/040412, Amoco Corporation
  • L N Venkateshwaran
  • D Chokshi
  • W L Chiang
  • B C Tsai
Venkateshwaran LN, Chokshi D, Chiang WL, Tsai BC. Oxygen scavenging composition. WO/1996/040412, Amoco Corporation, 1996.
CibaShelfplusO2 Oxygen Absorbers
  • Anonymous
Anonymous. CibaShelfplusO2 Oxygen Absorbers. Technical Data Sheet, Basel, Switzerland: Ciba Specialty Chemicals, Inc, 2000.
  • Anonymous
  • Lupolen
Anonymous. Lupolen 1806H. Technical Data Sheet. Basell Service Company B.V., 2009.
Verfahren und Vorrichtung zur Bestimmung der Haltbarkeit von Lebensmitteln und dessen Verwendung. DE 195 28 400, Fraunhofer Gesellschaft zur Förderung der angewandten Forschung e
  • K Rieblinger
  • G Ziegleder
  • A Berghammer
  • D Sandmeier
Rieblinger K, Ziegleder G, Berghammer A, Sandmeier D. Verfahren und Vorrichtung zur Bestimmung der Haltbarkeit von Lebensmitteln und dessen Verwendung. DE 195 28 400, Fraunhofer Gesellschaft zur Förderung der angewandten Forschung e.V., 1995.
New Permeation Measurement Device using Optical Sensor Spots. 25th IAPRI Symposium on Packaging
  • Huber Ch
  • S Saengerlaub
  • K Mueller
Huber Ch, Saengerlaub S, Mueller K. New Permeation Measurement Device using Optical Sensor Spots. 25th IAPRI Symposium on Packaging. Berlin 2011.