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Stuttgart, Germany

The Deutsche Forschungsanstalt für Segelflug, or DFS was formed in 1933 to centralise all gliding activity in Germany, under te directorship of Professor Georgii. It was formed by the nationalisation of the Rhön-Rossitten Gesellschaft at Darmstadt.The DFS was involved in producing training sailplanes for the Hitler Youth and Luftwaffe, as well as conducting research into advanced technologies such as flying wings and rocket propulsion. Notable DFS-produced aircraft include the DFS 230 transport glider , the German counterpart to the British Airspeed Horsa glider, and the DFS 194 forerunner of the famous Messerschmitt Me 163 rocket fighter.In 1938, following a fatal accident at the Wasserkuppe, DFS held a competition to design a more effective speed brake for gliders. The final design, produced by Wolfgang and Ulrich Hütter of Schempp-Hirth, is used to this day and generally referred to as the "Schempp-Hirth brake". ) Wikipedia.


Steinhaus M.,German Research Center for Food Chemistry
Journal of Agricultural and Food Chemistry | Year: 2015

Curry leaves are a popular seasoning herb with a pronounced sulfury and burnt odor, the molecular background of which was yet unclear. Application of an aroma extract dilution analysis to the volatile fraction of curry leaves isolated by solvent extraction and solvent-assisted flavor evaporation afforded 23 odor-active compounds with flavor dilution (FD) factors ranging from 1 to 8192. On the basis of the comparison of their retention indices, mass spectra, and odor properties with data of reference compounds, the structures of 22 odorants could be assigned, 15 of which had not been reported in curry leaves before. Odorants with high FD factors included 1-phenylethanethiol (FD factor 8192), linalool (4096), α-pinene (2048), 1,8-cineole (1024), (3Z)-hex-3-enal (256), 3-(methylsulfanyl)propanal (128), myrcene (64), (3Z)-hex-3-en-1-ol (32), and (2E,6Z)-nona-2,6-dienal (32). The unique sulfury and burnt odor exhibited by 1-phenylethanethiol in combination with its high FD factor suggested that it constitutes the character impact compound of fresh curry leaf aroma. © 2015 American Chemical Society. Source


Krautwurst D.,German Research Center for Food Chemistry | Kotthoff M.,Fraunhofer Institute for Molecular Biology and Applied Ecology
Methods in Molecular Biology | Year: 2013

Smell is a multidimensional chemical sense. It creates a perception of our odorous environment by integrating the information of a plethora of volatile chemicals with other sensory inputs, emotions and memories. We are almost always exposed to odorant mixtures, not just single chemicals. Olfactory processing of complex odorant mixtures, such as coffee or wine, fi rst is decoded at the site of perception by the hundreds of different olfactory receptor types, each residing in the cilia of their olfactory sensory neurons in the nose. Often, only a few odorants from many are essential to determine complex olfactory perception. But merely using the chemical structure of odorants is insuf fi cient to identify and predict characteristic odor qualities and low odor thresholds. An understanding of odorant coding critically depends on knowledge about the interaction of key odorants of biologically relevant odor bouquets with their best cognate receptors. Here, we describe a hit map-based method of correlating the information content of all bioassay-tested odorants with their cognate odorant-receptor frequency in four phylogenetic subsets of human olfactory/chemosensory receptors. © Springer Science+Business Media, LLC 2013. Source


Kiefl J.,German Research Center for Food Chemistry | Schieberle P.,German Research Center for Food Chemistry
Journal of Agricultural and Food Chemistry | Year: 2013

The majority of the world hazelnut crop is roasted, thus developing a unique aroma that depends on the cultivar used and on the roasting conditions applied. Although several studies have investigated the volatile fraction of different cultivars and have correlated the data with overall sensory profiles, studies establishing a correlation between key odorants among the bulk of odorless volatiles and the respective aroma profiles are not yet available. On the basis of recently published stable isotope dilution assays (SIDAs) using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF-MS), differences in concentrations of key odorants in different hazelnut cultivars roasted under defined conditions were monitored and compared with sensory data obtained by projective mapping, aroma profile analysis, and triangle tests. The results showed that the aroma-active compounds 2-acetyl-1-pyrroline, 2-propionyl-1-pyrroline, 5-methyl-(E)-2-hepten-4-one, 2,3-diethyl-5-methylpyrazine, 3,5-dimethyl-2-ethylpyrazine, and 2-furfurylthiol are appropriate marker odorants to differentiate the various nut aromas. In particular, the appreciated roasty, nutty aroma of optimally roasted hazelnuts was developed if both 5-methyl-(E)-2-hepten-4-one and 3-methyl-4-heptanone were >450 μg/kg, whereas the sum of the two 2-acyl-1-pyrrolines and two pyrazines should not exceed 400 μg/kg to avoid an over-roasted smell. Such a desired aroma can be obtained for each cultivar, but obviously specific roasting times, temperatures, and roasting techniques had to be applied. © 2013 American Chemical Society. Source


Wieser H.,German Research Center for Food Chemistry | Koehler P.,German Research Center for Food Chemistry
Journal of AOAC International | Year: 2012

Celiac disease (CD) is an inflammatory disease of the upper small intestine in genetically predisposed individuals caused by glutamine- and proline-rich peptides from cereal storage proteins (gluten) with a minimal length of nine amino acids. Such peptides are insufficiently degraded by gastrointestinal enzymes; they permeate the lymphatic tissue, are bound to celiac-specific, antigen-presenting cells, and stimulate intestinal T-cells. The typical clinical pattern is a flat small intestinal mucosa and malabsorption. Currently, the only therapy is a strict, lifelong gluten-free diet. Recent research has shown that gluten and gluten peptides can be degraded by prolyl endopeptidases from different sources. These peptidases can either be used to produce gluten-free foods from gluten-containing raw materials, or they have been suggested as an oral therapy for CD, in which dietary gluten is hydrolyzed by coingested peptidases already in the stomach, thus preventing CD-specific immune reactions in the small intestine. This would be an alternative for CD patients to the gluten-free diet. Furthermore, microbial transglutaminase could be used to detoxify gluten either by selectively modifying glutamine residues of intact gluten by transamidation with lysine methyl ester or by crosslinking gluten peptides in beverages via isopeptide bonds so that they can be removed by filtration. © 2012 Publishing Technology. Source


Lutz E.,German Research Center for Food Chemistry | Wieser H.,German Research Center for Food Chemistry | Koehler P.,German Research Center for Food Chemistry
Journal of Agricultural and Food Chemistry | Year: 2012

Disulfide bonds within gluten proteins play a key role in the breadmaking performance of wheat flour. In the present study, disulfide bonds of wheat gluten proteins were identified by using a new liquid chromatography-mass spectrometry (LC-MS) technique with alternating electron transfer dissociation (ETD)/collision-induced dissociation (CID). Wheat flour was partially hydrolyzed with thermolysin (pH 6.5, 37 °C, 16 h), and the digest was subjected to LC-MS with alternating ETD/CID fragmentation. Whereas CID provided peptide fragments with intact disulfide bonds, cleavage of disulfide bonds was preferred over peptide backbone fragmentations in ETD. The simultaneous observation of disulfide-linked and disulfide-cleaved peptide ions in the mass spectra not only provided distinct interpretation with high confidence but also simplified the conventional approach for determination of disulfide bonds, which often requires two separate experiments with and without chemical reduction. By application of the new method 14 cystine peptides were identified. Eight peptides confirmed previously established disulfide bonds within gluten proteins, and the other six cystine peptides were identified for the first time. One of the newly identified cystine peptides represented a "head-to-tail" cross-link between high molecular weight glutenin subunits. This type of cross-link, which has been postulated as an integral part of glutenin models published previously, has now been proven experimentally for the first time. From the six remaining cystine peptides interchain disulfide bonds between α-gliadins, γ-gliadins, and low molecular weight glutenin subunits were established. © 2012 American Chemical Society. Source

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