Detection and Identification of Oestrogen‐Active Substances in Plastic Food Packaging Migrates

Migrates from plastic food packaging were tested for oestrogen activity by yeast oestrogen screen and subsequently analysed by gas chromatography—mass spectrometry and high‐performance liquid chromatography—mass spectrometry to identify oestrogen‐active chemicals. Plastic samples were migrated according to EC 10/2011 with worst case scenarios being used. Food simulants consisted of either 10–95% ethanol or ultrapure water. Migrates were concentrated afterwards by solid phase extraction. Food contact material tested included polyethylene terephthalate, polypropylene, polyethylene, polystyrene and composite films. Oestrogenic activity ranging from 0.7 to 59 ng/l 17ß‐estradiol equivalents was detected in seven out of 42 samples tested. The highest activity was found in a composite film sample. All 11 polyethylene terephthalate samples tested negative for oestrogen activity. A number of chemicals with known or supposed oestrogen activity were identified in migrates of oestrogen‐active samples. These include butylated hydroxytoluene, 1,3‐diphenylpropane, 1,2‐diphenylcyclobutane and dibutyl phthalate. Copyright © 2013 John Wiley & Sons, Ltd.     

The Effect of High Pressure Processing on the Integrity of Polymeric Packaging – Analysis and Categorization of Occurring Defects

As high‐pressure processing is used increasingly for the treatment of packed products, different packaging has been investigated with respect to their structural behaviour and stability under high‐pressure processing. Often, failures and changes of the polymeric structure occur. Common damage symptoms of high‐pressure‐treated packaging materials are defined and classified in this review. These damage symptoms are allocated to the physico‐chemical effects that created them. The effects may be separated into direct effects induced by the action of the high‐pressure alone and indirect effects that are mediated via compressed contents of the package, i.e. filled product and gaseous headspace. The direct effects split up again in reversible and irreversible structural changes. The indirect effects are generated by compressed headspace gases, other compressed substances and the consequences of increased amounts of gases dissolved in the polymers. If applicable, current theoretical approaches have been allocated to the different categories of damage. Copyright © 2013 John Wiley & Sons, Ltd.     

DLC‐coated pure bioplastic foil

Polymers made of renewable resources increasingly replace conventional plastic materials made of petroleum. Socalled bioplastics can be found e. g. in food industry, for agricultural usage or in the medical field. The range of applications can be further expanded with specialized coating of their surface. Especially in case of food packaging and the usage within medical devices as well as the storage of these composite materials, sterilization or at least the partial reduction of microbial growth is an important issue which needs to be addressed early in the production process. In this work, a commercially available polyhydroxyalkanoate (PHA) pure bioplastic foil of 50 μm thickness was coated with 100 nm of diamond‐like carbon (DLC) and afterwards treated by four different standard methods of sterilization and / or disinfection, namely deep‐freezing, ultraviolet irradiation, autoclaving and immersion in ethanol. The surface morphology of treated DLC‐coated and uncoated samples was investigated and compared to the untreated DLC‐coated and uncoated samples using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Measurements exhibited damage of the composite for autoclaved and in ethanol immersed samples, whereas deep‐frozen and ultraviolet irradiated samples showed no structural changes. These findings clearly demonstrate deep‐freezing and ultraviolet irradiation to be appropriate methods for the disinfection and sterilization, respectively, of the DLC‐coated pure bioplastic foil.     

Endotoxins affect diverse biological activity of chitosans in matters of hemocompatibility and cytocompatibility

Chitosan is used in several pharmaceutical and medical applications, owing to its good cytocompatibility and hemocompatibility. However, there are conflicting reports regarding the biological activities of chitosan with some studies reporting anti-inflammatory properties while others report pro-inflammatory properties. In this regards we analyzed the endotoxin content in five different chitosans and examined these chitosans with their different deacetylation degrees for their hemocompatibility and cytocompatibility. Therefore, we incubated primary human endothelial cells or whole blood with different chitosan concentrations and studied the protein and mRNA expression of different inflammatory markers or cytokines. Our data indicate a correlation of the endotoxin content and cytokine up-regulation in whole blood for Poly-Morpho-Nuclear (PMN)-Elastase, soluble terminal complement complex SC5b-9, complement component C5/C5a, granulocyte colony-stimulating factor, Interleukin-8 (IL), IL-10, IL-13, IL-17E, Il-32α and monocyte chemotactic protein-1. In contrast, the incubation of low endotoxin containing chitosans with primary endothelial cells resulted in increased expression of E-selectin, intercellular adhesion molecule-1, vascular cell adhesion protein-1, IL-1β, IL-6 and IL-8 in endothelial cells. We suggest that the endotoxin content in chitosan plays a major role in the biological activity of chitosan. Therefore, we strongly recommend analysis of the endotoxin concentration in chitosan, before further determining if it has pro- or anti-inflammatory properties or if it is applicable for pharmaceutical and medical fields.     

An All Low‐Temperature Fabrication of Macroporous,Electrochemically Addressable Anatase Thin Films

Macroporous TiO₂ (anatase) thin films are fabricated by an all low‐temperature process in which substrates are dip‐coated in suspensions of mixed anatase nanoparticles and polystyrene beads, and the templating agents are removed by ultraviolet (UV) irradiation at a temperature below 50 °C. Scanning electron microscopy (SEM) and Raman spectroscopy show that the templating polymer beads are removed by UV irradiation combined with the photocatalytic activity of TiO₂. X‐Ray diffraction reveals that nanoparticle growth is negligible in UV irradiated films, while nanoparticle size increases by almost 10 times in calcined films that are prepared for comparison. The macroporous films are prepared on FTO‐(fluorine‐doped tin oxide) coated glass and ITO (indium tin oxide) coated flexible plastics and thereby used as working electrodes. In both cases, the films are electrochemically addressable, and cyclic voltammetry is consistent with the response of bulk TiO₂ for calcined films and of nanoscale‐TiO₂ for UV‐irradiated films.