A New Validation of Relevant Substances for the Evaluation of Beer Aging Depending on the Employed Boiling System

During the last years changes in aging indicators have been observed, supposedly resulting from modern brewing technology. The Research Brewery Weihenstephan (Forschungsbrauerei Weihenstephan) offers excellent opportunities for comparing different modern wort boiling systems under semi‐industrial conditions. Employing three different boiling systems, nine brews were produced. The resulting worts were compared regarding the most common wort parameters. Furthermore the influence of the different boiling systems on aging indicators in the resulting beers was analyzed using a newly developed mass spectrometry‐based method. The decrease in the total amount of aging indicators in industrial beers over the last years is very likely the result of lower thermal intake in modern brewhouse equipment. The total amount of aging indicators is sufficient to describe the differences in modern boiling systems. In summary, 2‐furfural dominates all other indicators in terms of thermal influence. 2‐Furfuryl ethyl ether can be suggested as good indicator of aging as postulated by Eichhorn, whereas β‐damascenone is questionable as an aging indicator. Supplementary experiments were carried out to investigate the role of the aging indicators as stale flavour components. Because of synergistic effects, many stale flavour compounds act as aroma compounds and not only as indicators.     

Catalyst development for oxidative methane coupling

The heterogeneously catalyzed oxidative coupling of methane has been investigated for several catalysts. A Ce/Li/MgO system was found to be the most attractive catalyst. The regeneration of the active sites seems to play a major role in the radical generating mechanism. The influence of the operating conditions on the conversion/selectivity has been studied, in order to find conditions for an optimal yield of C₂₊ - hydrocarbons. It is demonstrated that it is unrewarding to compare different types of catalysts only under selected standard conditions.     

Thesen und Trends – Mit funktionalen Oberflächen in die Zukunft

Propositions and Trends – With Functional Surfaces into the Future Functional surfaces are the key to innovative products. Already today the properties, lifetime, and costs for most industrial and consumer products are determined by functionalised surfaces. Three Fraunhofer Institutes supported by the BMBF investigated the actual state of the art of production technology regarding functional surfaces, their future perspectives and the research and development demand. The results are published in the study “Production technology for the generation of functional surfaces” available at info@ist.‐ fraunhofer.de and the essentials are summarised in this article.     

Electrospray: From ions in solution to ions in the gas phase,what we know now

There is an advantage for users of electrospray and nanospray mass spectrometry to have an understanding of the processes involved in the conversion of the ions present in the solution to ions in the gas phase. The following processes are considered: Creation of charge droplets at the capillary tip; Electrical potentials required and possibility of gas discharges; Evolution of charged droplets, due to solvent evaporation and Coulomb explosions, to very small droplets that are the precursors of the gas phase ions; Production of gas phase ions from these droplets via the Ion Evaporation and Charge residue models; Analytical uses of ESIMS of small ions, qualitative and quantitative analysis; Effects of the ESI mechanism on the analysis of proteins and protein complexes; Determination of stability constants of protein complexes; Role of additives such as ammonium acetate on the observed mass spectra. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 28:898–917, 2009     

Die Restspannungen in der Umgebung der kaltverfestigten Bohrung

Zusammenfassung Gegenstand der Untersuchung ist die Spannungsverteilung in der unendlichen elastisch-plastischen Scheibe, die durch die Druckbelastung einer kreisf?rmigen Bohrung hervorgerufen wird. Der Rechnung liegt die Trescasche Flie?bedingung, die zugeordnete Flie?regel sowie lineare isotrope Verfestigung zugrunde. Bestimmt werden ferner die Restspannungen und die Aufweitung der Bohrung.