Characterization of silicium dioxide (SiO2) nanoparticles in E 551-containing instant coffee products by Scanning Electron Microscopy (SEM) combined with Energy-dispersive X-ray spectroscopy (EDX)

Silicon dioxide (SiO2, amorphous silica) is a food additive approved in the EU with defined purity criteria and bears the designation number E 551. In coffee instant products and other types of powdered food products, E 551 is mainly used as a separating agent or anti-caking agent. Silicon dioxide as a food additive is under public discussion due to controversial views on the declaration obligation of the substance as an engineered nanomaterial. According to the Food Information Regulation (EU) No. 1169/2011, all food ingredients that are present in a food in the form of engineered nanomaterials must be clearly listed in the list of ingredients. The name of such ingredients must be followed by the word "nano" in brackets. So far, there are only very few E 551-containing foods on the market with nano-labelling of E 551 on the ingredient list. The analysed instant coffee products had no such nano-labelling. The food additive is an industrially manufactured material, consisting of amorphous agglomerated and aggregated granules whose particle sizes are mainly in the microscale size range. However, these aggregates consist of nanoscaled constituent particles (also called “primary particles”). This dataset contains SEM images showing the morphology of SiO2 aggregates in three commercially available instant coffee products containing E 551. In the high magnification images (100.000x) the constituent nanoparticles can be visualised. Basic information about the SEM setup and the sample preparation can be found in the attached txt-file (“Instant coffee_SEM analysis_Equipment_Sample info_Sample preparation.txt”). All in all, the obtained SEM results show, that E 551 in all three instant coffee products is present in aggregated form and is deposited on the other food components, fulfilling its purpose as anti-caking agent. The primary particle sizes of SiO2 particles within the aggregates are in the size range of ca. 30 – 60 nm

Characterization of silicium dioxide (SiO2) nanoparticles in the food additive E 551 by Scanning Electron Microscopy (SEM) combined with energy-dispersive x-ray spectroscopy (EDX)

Silicon dioxide (SiO2, amorphous silica) is a food additive approved in the EU with the designation number E 551. It is mainly used in powdered foods as a separating agent or anti-caking agent. Furthermore, it can be used as filler and as carrier for emulsifiers, colourings and flavourings. Silicon dioxide as a food additive is under public discussion due to controversial views on the declaration obligation of the substance as an engineered nanomaterial. According to the Food Information Regulation (EU) No. 1169/2011, all food ingredients that are present in a food in the form of engineered nanomaterials must be clearly listed in the list of ingredients. The name of such ingredients must be followed by the word "nano" in brackets. So far, there are only very few E 551-containing foods on the market with nano-labelling of E 551. The SiO2 used for this purpose is an industrially manufactured product in powdered form. It consists of amorphous agglomerated and aggregated granules whose particle sizes are mainly in the microscale size range. However, these aggregates consist of nanoscaled constituent particles (also called “primary particles”). This dataset contains SEM images showing the morphology of SiO2 aggregates in the pristine food additive called “Sipernat®22S”. In the high magnification images (50.000x - 300.000x) the constituent nanoparticles can be visualised. Basic information about the SEM setup and the sample preparation can be found in the attached txt-file. All in all, the obtained SEM results show, that the primary particles size of SiO2 particles within the aggregates are in the size range of ca. 15 – 30 nm

Methodische Weiterentwicklung der Laser-induzierten Breakdown-Detektion (LIBD) und ihre Anwendung auf kolloidchemische Fragestellungen

Die Laser-induzierte Breakdown-Detektion (LIBD) konnte in den letzten zwanzig Jahren zu einer etablierten Methode zur quantitativen Charakterisierung von Kolloiden in aquatischen Systemen entwickelt werden. Sie ermöglicht die Bestimmung eines mittleren Kolloid-Durchmessers und der Anzahl- sowie Massenkonzentration (bei bekannter Dichte der Kolloide) in bisher nicht erreichten Größen- und Konzentrationsbereichen. Das Detektionsspektrum der entwickelten Instrumentierung liegt im Bereich zwischen ~ 20 nm und 1000 nm, wobei die Nachweisgrenze abhängig vom Partikeldurchmesser im Bereich von wenigen ng/L (entspricht 1e8 Partikel/L für 20 nm-Kolloide) bis hin zu einigen mg/L (entspricht 1e7 Partikel/L für 1000 nm-Kolloide1) reicht. Damit weist die LIBD im Vergleich zu konkurrierenden Methoden auf Basis der Laserlichtstreuung eine um mehrere Größenordnungen höhere Nachweisempfindlichkeit auf, wodurch sie insbesondere bei der nicht-invasiven Charakterisierung von kolloidarmen System bzw. von Kolloiden (Nanopartikeln) unter 100 nm die Methode der Wahl ist. Ein Schwerpunkt in dieser Arbeit lag in der methodischen Weiterentwicklung auf Basis der bisherigen Funktionalitäten der am Institut entwickelten Anlage � sowohl bezüglich der Datenevaluation als auch der Benutzerfreundlichkeit und der Optimierung der Anlage für die Anwendung auf neue kolloidchemische Fragestellungen. Der zweite Schwerpunkt der Arbeit bestand darin, das hohe Potential der LIBD-Technik mit ihren erweiterten Funktionalitäten als kolloidanalytische Methode durch den Einsatz bei verschiedenen Fragestellungen der aquatischen Kolloidchemie zu belegen. Neben der Analyse des partikulären Austrags aus Recyclingmaterialien und der Untersuchung von biogenen Fällungsprozessen in natürlichen Gewässern wurden im Rahmen eines dreijährigen Forschungsprojekts Trinkwasseraufbereitungsverfahren auf Basis der Membranfiltrationstechnologie untersucht. Die Filtrationseffizienz und Filtratqualität wurde an vier verschiedenen Standorten, die eine klein- oder großtechnische Membrananlage besitzen, erstmals mittels NPA/LIBD untersucht, indem Membranzu- und Abläufe systematisch bezüglich ihres Kolloid-Inventars charakterisiert wurden. Des Weiteren erfolgten umfassende Unter¬suchungen zum Foulingpotential (Verblocken der Membranen) von natürlichen Rohwässern (d. h. ihre Tendenz zum Verblocken der mit den Rohwässern beaufschlagten Membranen) und zur Membranintegrität von Ultra- und Mikrofiltrationsmembranen

Surface wax in the ancestral grapevine Vitis sylvestris correlate with partial resistance to Powdery Mildew

Background Powdery Mildew of Grapevine belongs to the major diseases in viticulture and requires intensive use of fungicides. Genetic introgression of resistance factors from wild grapes from North America and, recently, China, has been successful, but wine made from those varieties is still confronted with low consumer acceptance, due to differences in taste. Results The current work explores the potential of Vitis vinifera sylvestris, the wild ancestor of domesticated Grapevine, with respect to containing Erysiphe necator, the causative agent of Powdery Mildew. Making use of a germplasm collection comprising the entire genetic variability remaining in Germany, we show that there is considerable genetic variation in the formation of leaf surface waxes exceeding wax formation in commercial varieties. Conclusions High wax formation correlates with reduced susceptibility to controlled infection with E. necator linked with perturbations of appressoria formation. We propose V. vinifera sylvestris as novel source for resistance breeding since it is genetically much closer to domesticated grapevine than the hitherto used sources from beyond the species barrier