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News Article | February 17, 2017
Site: www.cemag.us

The Fraunhofer Institute for Process Engineering and Packaging IVV, together with the Fraunhofer Institute for Applied Polymer Research IAP and the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, have developed new developments in films and the efficient control of coating processes. The development of a cost-effective, optical measuring system means that coating processes will in the future be able to be fully controlled and monitored over the entire substrate surface. The degree of crosslinking and thickness of organic coatings can be controlled inline via automated coupling of the measurement system to the coating unit. This prevents issues such as delamination, poor processing of web-shaped materials, and increased migration of non-crosslinked adhesive components. High-barrier laminates manufactured in roll-to-roll processes for the encapsulation of flexible solar cells and electronic components must have as low as possible oxygen and water vapor permeability. For quality assurance, it is a challenge to measure the permeability of such films over long periods of time. The tests can take several months. Now, however, the Fraunhofer IVV has developed a device for measuring the permeability of ultra barrier films in combination with associated computer software for simulating the permeation process. This enables the water vapor permeability to be determined 3 to 4 times faster than with conventional methods. The Fraunhofer IVV has acquired a new coating plant which utilizes atomic layer deposition to further reduce the permeability of films. Minimizing the permeability to water vapor and oxygen is the key to successful further improvement of high barrier films. Atomic layer deposition (ALD) is paving the way here. Coating via roll-to-roll processes allows high processing speeds and production efficiency to be achieved. Up until now, films with the highest barriers have been produced exclusively in vacuum processes. The new ALD plant at the Fraunhofer IVV enables the barrier properties of films to be significantly improved. This is a further step towards meeting the permeability requirements for OLED encapsulation in the medium term. The Fraunhofer IVV is using this technology for publicly funded R&D projects and to provide industry with customized solutions and research services for the development of processes and materials. The formation of ice on the rotor blades of wind turbines results in aerodynamic imbalance. In order to prevent damage, either the rotor blades must be heated or the wind turbine must be shut down. To tackle this issue, the Fraunhofer IGB has developed a number of anti-icing coatings suitable for polymer surfaces. These water-repelling microstructured and nanostructured coatings ensure that any water remains a liquid, even at temperatures below zero, resulting in a 90 percent reduction in ice adhesion compared to uncoated surfaces. The trick: The surfaces provide the water molecules with no crystallization nuclei. Plasma technology is used to deposit the structured coatings onto plastic films made of impact-resistant polyurethane (PU). The coatings are not only of interest for wind turbines: these functional surfaces can also be applied to aircraft wings and solar panels. Furthermore, anti-icing coatings can also be directly applied to fabrics and plastics, for example for winter sports clothing, tents, and other outdoor articles. Regardless of whether the requirement is for anti-fouling and easy-to-clean surfaces, printable films, or eco-friendly water-repelling textiles, the Fraunhofer IGB usually uses plasma processes to create these new surface properties. Plasma processes allow the top layers to be removed, so generating pristine surfaces and enabling chemical functionalities or other layers to be applied. Selection and control of the chemical processes enable the scientists at the Fraunhofer IGB to customize the surface energy and hence the wetting properties. This enables even textiles to be effectively equipped with water-repelling or oil-repelling properties — in an eco-friendly way without harmful byproducts or waste products. Whilst the properties of most synthetic materials are fixed, many biological systems have the ability to adapt to changing environmental conditions. Materials are, however, now being developed with properties which "change" on exposure to external stimuli. These so-called "intelligent" materials change, for example, when exposed to various physical and chemical stimuli such as temperature, light intensity, and pH or due to biomolecules such as proteins. This is being achieved using special polymers developed by the Fraunhofer IAP. This development work is being supported by surface technologies which allow even these intelligent materials to be manufactured on a large scale in roll-to-roll processes. In addition to classical methods such as corona and plasma treatment, printing methods (entire surface or structured) are widely used for the functionalization of surfaces.


News Article | December 15, 2016
Site: www.eurekalert.org

A researcher in Germany is studying why fish sometimes smells 'fishy' and why customers often smell other aromas when they buy fish. Mohamed Mahmoud, doctoral candidate at the Department of Chemistry and Pharmacy at FAU, identified various off-flavours of fish raised in aquaculture as part of his doctoral thesis. His goal is to discover how to reduce unpleasant musty notes in the taste of fish. Eating fish as part of a high-protein diet is healthy - which is why more and more people have put salmon and other types of fish on the menu. However, this trend also means that as the demand for wild-caught fish increases, natural resources are gradually depleted. The ecological balance is disturbed, threatening long-term food security around the world. 'This is why aquacultures where fish are raised are important,' explained Prof. Dr. Andrea Büttner from the Chair of Food Chemistry at FAU's Emil Fischer Centre. However, there is one clear disadvantage to farm-raised fish from the consumers' perspective: they often have undesirable flavours. 'Microorganisms can form in aquaculture ponds and other substances can successively break down in the water, creating highly potent aromas which in turn cause deficiencies in the fish,' explained Prof. Büttner. The musty, earthy smell, for example, is typically caused by two substances: geosmin, which has an earthy, musty, or mouldy smell, and the chemical compound 2-methylisoborneol (MIB), which has a rotten fish smell. It was previously assumed that these substances were primarily responsible for off-flavours in fish. It was unclear whether other culprits might be responsible for fishy smells. Manure smell most likely from livestock husbandry Doctoral candidate Mohamed Mahmoud's experiments are intended to find answers to this question. The young researcher recently conducted a successful experiment on rainbow trout aquaculture. In addition to geosmin and MIB, he identified ten other substances with a musty-earthy smell, including one that smells like manure. 'The manure smell most likely comes from livestock husbandry, such as pig farms, but other substances appear to be the result of odour-producing disintegration of pesticides. These substances run off over land into the water and get into the fish,' said Mahmoud. This made it clear that the conventional wisdom on this matter needs to be looked at more critically and that the sources of flavour problems are significantly more complex than previously assumed. Mahmoud's main goal is to discover ways to avoid off-flavours in farm-raised fish, as aquaculture is certain to play an even bigger role in future. The variety of aromas typical for fish The combinations of various aromas typical for fish are of great interest for Mahmoud. 'When you look at the components of fish aromas, it's interesting that you also find unexpected substances.' The young researcher has identified aromas in fish that smell like, for example, geraniums, citrus, eucalyptus, caramel, peach or black pepper. 'It isn't unusual; food aromas are generally very complex and it's difficult to identify the individual components of an overall aroma - unless you use our targeted analytics which allow you to individually identify aromatic substances,' explained Mahmoud. 'Our main goal is still to find, among all the possible substances, exactly those substances that are perceived negatively and that aren't typical for fish - especially in comparison with wild-caught fish. We are working to find more potential causes of off-flavours in aquaculture fish produced in Germany and to identify the links between water quality and aroma profiles.' Together with the Fraunhofer Institute for Process Engineering and Packaging IVV in Freising, Mohamed Mahmoud is conducting sensory tests of fish, aquaculture pond water, and added and drained water. He uses gas chromatography-olfactometry, which allows for odour-producing substances to be detected and analysed.


News Article | December 15, 2016
Site: phys.org

Eating fish as part of a high-protein diet is healthy - which is why more and more people have put salmon and other types of fish on the menu. However, this trend also means that as the demand for wild-caught fish increases, natural resources are gradually depleted. The ecological balance is disturbed, threatening long-term food security around the world. 'This is why aquacultures where fish are raised are important,' explained Prof. Dr. Andrea Büttner from the Chair of Food Chemistry at FAU's Emil Fischer Centre. However, there is one clear disadvantage to farm-raised fish from the consumers' perspective: they often have undesirable flavours. 'Microorganisms can form in aquaculture ponds and other substances can successively break down in the water, creating highly potent aromas which in turn cause deficiencies in the fish,' explained Prof. Büttner. The musty, earthy smell, for example, is typically caused by two substances: geosmin, which has an earthy, musty, or mouldy smell, and the chemical compound 2-methylisoborneol (MIB), which has a rotten fish smell. It was previously assumed that these substances were primarily responsible for off-flavours in fish. It was unclear whether other culprits might be responsible for fishy smells. Manure smell most likely from livestock husbandry Doctoral candidate Mohamed Mahmoud's experiments are intended to find answers to this question. The young researcher recently conducted a successful experiment on rainbow trout aquaculture. In addition to geosmin and MIB, he identified ten other substances with a musty-earthy smell, including one that smells like manure. 'The manure smell most likely comes from livestock husbandry, such as pig farms, but other substances appear to be the result of odour-producing disintegration of pesticides. These substances run off over land into the water and get into the fish,' said Mahmoud. This made it clear that the conventional wisdom on this matter needs to be looked at more critically and that the sources of flavour problems are significantly more complex than previously assumed. Mahmoud's main goal is to discover ways to avoid off-flavours in farm-raised fish, as aquaculture is certain to play an even bigger role in future. The variety of aromas typical for fish The combinations of various aromas typical for fish are of great interest for Mahmoud. 'When you look at the components of fish aromas, it's interesting that you also find unexpected substances.' The young researcher has identified aromas in fish that smell like, for example, geraniums, citrus, eucalyptus, caramel, peach or black pepper. 'It isn't unusual; food aromas are generally very complex and it's difficult to identify the individual components of an overall aroma - unless you use our targeted analytics which allow you to individually identify aromatic substances,' explained Mahmoud. 'Our main goal is still to find, among all the possible substances, exactly those substances that are perceived negatively and that aren't typical for fish - especially in comparison with wild-caught fish. We are working to find more potential causes of off-flavours in aquaculture fish produced in Germany and to identify the links between water quality and aroma profiles.' Together with the Fraunhofer Institute for Process Engineering and Packaging IVV in Freising, Mohamed Mahmoud is conducting sensory tests of fish, aquaculture pond water, and added and drained water. He uses gas chromatography-olfactometry, which allows for odour-producing substances to be detected and analysed. Explore further: Video: How to make fish less fishy More information: Mohamed Ahmed Abbas Mahmoud et al, Characterisation of aroma-active and off-odour compounds in German rainbow trout (Oncorhynchus mykiss). Part I: Case of aquaculture water from earthen-ponds farming, Food Chemistry (2016). DOI: 10.1016/j.foodchem.2016.05.030 Mohamed Ahmed Abbas Mahmoud et al. Characterisation of aroma-active and off-odour compounds in German rainbow trout (Oncorhynchus mykiss). Part II: Case of fish meat and skin from earthen-ponds farming, Food Chemistry (2016). DOI: 10.1016/j.foodchem.2016.09.172


Welle F.,Fraunhofer Institute for Process Engineering and Packaging
Resources, Conservation and Recycling | Year: 2011

Polyethylene terephthalate (PET) has become the most favourable packaging material world-wide for beverages. The reason for this development is the excellent material properties of the PET material, especially its unbreakability and the very low weight of the bottles compared to glass bottles of the same filling volume. Nowadays, PET bottles are used for softdrinks, mineral water, energy drinks, ice teas as well as for more sensitive beverages like beer, wine and juices. For a long time, however, a bottle-to-bottle recycling of post-consumer PET packaging materials was not possible, because of the lack of knowledge about contamination of packaging polymers during first use or recollection. In addition, the decontamination efficiencies of recycling processes were in most cases unknown. During the last 20 years, PET recollection as well as recycling processes made a huge progress. Today, sophisticated decontamination processes, so-called super-clean recycling processes, are available for PET, which are able to decontaminate post-consumer contaminants to concentration levels of virgin PET materials. In the 1991, the first food contact approval of post-consumer PET in direct food contact applications has been given for post-consumer recycled PET in the USA. Now, 20 years after the first food approval of a PET super-clean recycling process, this article gives an overview over the world-wide progress of the bottle-to-bottle recycling of PET beverage bottles, e.g. the recollection amount of post-consumer PET bottles and the super-clean recycling technologies. © 2011 Elsevier B.V. All rights reserved.


Welle F.,Fraunhofer Institute for Process Engineering and Packaging
Journal of Applied Polymer Science | Year: 2013

Poly(ethylene terephthalate) (PET) is used in several packaging applications, especially for beverages. Due to the low concentration of potential chemical compounds like polymer additives or monomers leached out of the polymers and found in food or beverages, the compliance of a PET packaging material is shown often by use of migration modeling. Diffusion coefficients for migrants, however, are rare in the scientific literature. The aim of the study was to develop an equation for the prediction of diffusion coefficients in PET on the basis of activation energies of diffusion for possible migrants in PET. As a result, a correlation between experimentally determined activation energies of diffusion EA and the volume of the migrant V was established for PET. In addition, a correlation of the pre-exponential factor D0 with the activation energy EA was found. Combining both correlations lead to an equation where the diffusion coefficients DP are predictable from the molecular volume V of the migrant. The equation might be useful for migration prediction and consumer exposure estimations. © 2012 Wiley Periodicals, Inc.


Schmid M.,Fraunhofer Institute for Process Engineering and Packaging | Schmid M.,TU Munich
Materials | Year: 2013

Whey protein isolate (WPI)-based cast films are very brittle, due to several chain interactions caused by a large amount of different functional groups. In order to overcome film brittleness, plasticizers, like glycerol, are commonly used. As a result of adding plasticizers, the free volume between the polymer chains increases, leading to higher permeability values. The objective of this study was to investigate the effect of partially substituting glycerol by hydrolysed whey protein isolate (h-WPI) in WPI-based cast films on their mechanical, optical and barrier properties. As recently published by the author, it is proven that increasing the h-WPI content in WPI-based films at constant glycerol concentrations significantly increases film flexibility, while maintaining the barrier properties. The present study considered these facts in order to increase the barrier performance, while maintaining film flexibility. Therefore glycerol was partially replaced by h-WPI in WPI-based cast films. The results clearly indicate that partially replacing glycerol by h-WPI reduces the oxygen permeability and the water vapor transmission rate, while the mechanical properties did not change significantly. Thus, film flexibility was maintained, even though the plasticizer concentration was decreased. © 2013 by the authors; licensee MDPI, Basel, Switzerland.


Welle F.,Fraunhofer Institute for Process Engineering and Packaging | Franz R.,Fraunhofer Institute for Process Engineering and Packaging
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2011

Plastics bottles made from polyethylene terephthalate (PET) are increasingly used for soft drinks, mineral water, juices and beer. In this study a literature review is presented concerning antimony levels found both in PET materials as well as in foods and food simulants. On the other hand, 67 PET samples from the European bottle market were investigated for their residual antimony concentrations. A mean value of 224 ± 32 mg kg -1 was found, the median was 220mg kg -1. Diffusion coefficients for antimony in PET bottle materials were experimentally determined at different temperature between 105 and 150°C. From these data, the activation energy of diffusion for antimony species from the PET bottle wall into beverages and food simulants was calculated. The obtained value of 189 kJ mol -1 was found to be in good agreement with published data on PET microwave trays (184 kJ mol -1). Based on these results, the migration of antimony into beverages was predicted by mathematical migration modelling for different surface/volume ratios and antimony bottle wall concentrations. The results were compared with literature data as well as international legal limits and guidelines values for drinking water and the migration limit set from food packaging legislation. It was concluded that antimony levels in beverages due to migration from PET bottles manufactured according to the state of the art can never reach or exceed the European-specific migration limit of 40 μgkg -1. Maximum migration levels caused by roomtemperature storage even after 3 years will never be essentially higher than 2.5 μgkg -1 and in any case will be below the European limit of 5 μgkg -1 for drinking water. The results of this study confirm that the exposure of the consumer by antimony migration from PET bottles into beverages and even into edible oils reaches approximately 1% of the current tolerable daily intake (TDI) established by World Health Organisation (WHO). Having substantiated such low antimony levels in PET-bottled beverages, the often addressed question on oestrogenic effects caused by antimony from PET bottles appears to be groundless. © 2011 Taylor & Francis.


Welle F.,Fraunhofer Institute for Process Engineering and Packaging
Resources, Conservation and Recycling | Year: 2013

For almost 15 years now in Europe, used plastic bottles made of polyethylene terephthalate (PET) have been recycled in such a way that the recyclate can be used for new PET bottles. Several recycling plants have been established all over Europe. Since May 2008 the European Recycling Regulation 282/2008 has been in force. According to this regulation, every recycling process must be individually approved by the European Food Safety Authority (EFSA). For this evaluation process, EFSA has developed a conservative evaluation concept in order to protect consumers. The evaluation is partly based on mathematical calculation of the migration. The current migration model overestimates the migration. EFSA acknowledges that the migration model overestimates by at least a factor of 5. This applies for small molecules such as toluene. However, higher molecular weight contaminants such as benzophenone are even more overestimated. The reason for this overestimation is that the currently used migration model is based on a fixed activation energy of diffusion. Conversely, the curve of the maximum bottle wall concentration calculated using the current migration model increases much too gradually with the molecular weight. New developments in migration modelling consider more precisely the activation energies of diffusion. Consequently, using the new, more realistic diffusion coefficients influences significantly the EFSA evaluation criteria. © 2013 Elsevier B.V.


Beauchamp J.,Fraunhofer Institute for Process Engineering and Packaging
Journal of Breath Research | Year: 2011

The chemical analysis of exhaled breath gas to assess state of health or identify disease biomarkers has gained growing interest in recent years, with advances in new technologies providing scientists and physicians with a powerful analytical arsenal with which to tackle pertinent issues. The application of these methods for pharmacokinetic studies, however, has received less attention despite its enormous potential in this field. For instance, breath gas analysis may be employed to characterize uptake and distribution within the body of exogenous volatile compounds, either from a pharmaceutical point of view, or in relation to environmental inhalation exposure. Both of these topics can benefit greatly from utilizing breath gas complementarily or as a surrogate to blood as an analytical medium, since breath sampling is non-invasive, inexhaustible, and is achievable with a frequency far exceeding that which is feasible for blood. However, because of the efficiency with which certain exogenous compounds are reflected in breath, this can also often be a significant source of confounding variables that require consideration in routine breath gas analyses. This paper provides an overview of the possibilities of breath gas analysis for pharmacokinetics and environmental exposure investigations and discusses the presence of exogenous compounds in standard breath analyses and their repercussions in terms of erroneous data interpretation. © 2011 IOP Publishing Ltd.


Herbig J.,IONICON Analytik GmbH | Beauchamp J.,Fraunhofer Institute for Process Engineering and Packaging
Journal of Breath Research | Year: 2014

Despite growing interest and considerable progress in breath research over the last decade, standardized practices for the sampling and analysis of breath gas volatiles remain elusive. The primary reasons for this are (a) the rich chemical diversity of exhaled breath that covers an extensive range of volatile organic compounds at highly varied concentrations, (b) the vast disparity in the analytical tools employed, (c) diverse study goals and (d) the presence of (unidentified) confounders. These aspects place stringent but divergent demands on sampling and analysis: each analytical tool, target compound and concentration range requires its own specific protocol and in many cases the latter two are not even known a priori. The ongoing rapid developments and constant discoveries in the field of breath research and the lack of established best practices in breath gas sampling and analysis currently preclude an acceptable overall standardization of these methods. This paper addresses these manifold issues and suggests a framework that separately considers individual stages of sampling and analysis with a view to establishing standardization in the analysis of breath gas volatiles to suit different target compounds and analytical technologies. © 2014 IOP Publishing Ltd.

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