Sicherheit in Kommunikationsnetzen — einige Trends und Entwicklungen

This article describes current developments in the area of security related Internet applications and its cryptographic basics. The most interesting trends, fields of applications and related problems are discussed. Finally, we focus on the topic of symmetric encryption algorithms.     

A comparative study of potent odorants in peanut,hazelnut, and pumpkin seed oils on the basis of aroma extract dilution analysis (AEDA) and gas chromatography-olfactometry of headspace samples (GCOH)

Potent odorants in commercially processed peanut, hazelnut, and pumpkin seed oils were evaluated by the application of aroma extract dilution analysis (AEDA) and gas chromatography-olfactometry of headspace samples (GCOH). AEDA revealed 38, 28 and 27 odour-active compounds in peanut, hazelnut, and pumpkin seed oils, respectively. Fifteen odorants were present in all oils; two of them showed the highest flavour dilution factor (FD-factor): 2-ethyl-3,5-dimethylpyrazine and 2,3-diethyl-5-methylpyrazine. Application of GCOH led to the identification of 21, 24, and 24 odorants in peanut, hazelnut, and pumpkin seed oils, respectively. Nine of them were found in all oils: acetaldehyde, propanal, 2-methylpropanal, 2- and 3-methylbutanal, 2-ethyl-3,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, (E)-2-nonenal and vanillin. The following odorants appeared with relative high FD-factors in the headspace of a single oil: 1-penten-3-one in peanut, 5-methyl-(E)-2-hepten-4-one (Filbertone) in hazelnut, (Z)-4-heptenal and 3-ethyl-2,5-dimethylpyrazine in pumpkin seed oil.     

Potent odorants of the wheat bread crumb Differences to the crust and effect of a longer dough fermentation

Summary Characterization of the crumb flavour of wheat bread by means of an aroma extract dilution analysis indicated diacetyl, methional, 1-octen-3-one, (Z)-and (E)-2-nonenal, (E,E)-2,4-decadienal andtrans-4,5-epoxy-(E)-2-decenal as the most potent odorants. The epoxydecenal had the lowest odour threshold (1.5 pg/L, air) among the homologous series oftrans-4,5-epoxy-(E)-2-alkenals C₇-C₁₁. Prolongation of the dough fermentation resulted in a change of the crumb flavour which was mainly due to an increase in the concentrations of 3-methylbutanol and 2-phenylethanol. Stable isotope dilution assays indicated that the concentrations of the roasty smelling flavour compounds 2-acetyl-1-pyrroline and 2-acetyltetrahydropyridine were 30-fold lower in the crumb than in the crust. (E)-2-Nonenal, which is present in the flour, increased strongly during the baking process.

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Intensive Geruchsstoffe der Weißbrotkrume Unterschiede zur Kruste und Auswirkung einer längeren Fermentation des Teigs

Zusammenfassung Durch eine Aromaextraktverdünnungsanalyse wurden Diacetyl, Methional, 1-Octen-3-on, (Z)- und (E)-2-Nonenal, (E,E)-2,4-Decadienal undtrans-4,5-Epoxy-(E)-2-decenal als intensivste Geruchsstoffe der Weißbrotkrume ermittelt. In der homologen Reihe dertrans-4,5-Epoxy-(E)-2-alkenale C₇-C₁₁ hatte das Epoxydecenal die niedrigste Geruchsschwelle (1,5 pg/L, Luft). Bei einer Verlängerung der Fermentation des Teigs veränderte sich das Aroma der Krume durch einen Anstieg der Konzentrationen von 3-Methylbutanol und 2-Phenylethanol. Isotopenverdünnungsanalysen ergaben für die röstig riechenden Aromastoffe 2-Acetyl-1-pyrrolin und 2-Acetyltetrahydropyridin 30mal niedrigere Konzentrationen in der Krume als in der Kruste. (E)-2-Nonenal, das schon im Mehl vorkam, nahm beim Backen stark zu.

     

Intensive neutral odourants of linden honey Differences from honeys of other botanical origin

Summary Aroma extract dilution analysis of linden honey volatiles resulted in 21 odour compounds having high factors of dilution (FD); 18 of these compounds were identified as 1-hexen-3-one, 2-acetyl-1 -pyrroline, dimethyl trisulphide, methional, phenylacetaldehyde, 2-phenylethanol, linalool, p-cresol, 3,9-epoxy-lpmenthene, 4-methylacetophenone, 3,9-epoxy-1,4(8)-p-menthadiene (linden ether), 1,3 p-menthadien-7-al, p-anisaldehyde, 4vinylguaiacol, (E)-p-damascenone, eugenol, vanillin andcis-rose oxide. Linden ether andcis-rose oxide, which were also found in an extract obtained from the blossoms of the lime tree (Tifa cordata), were absent in honeys of other botanical origin. These two odourants and the odourlesstrans-limonene-1,2-diol are proposed as indicators for linden honey. The odour thresholds (in air) of the 18 aroma compounds are reported.

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Intensive neutrale Geruchsstoffe von Lindenhonig. Unterschiede zu Honigen anderer botanischer Herkunft

Zusammenfassung Die Aromaextrakt-Verdünnungs-analyse der flüchtigen Verbindungen aus Lindenhonig ergab 21 Geruchsstoffe mit hohen FD-Faktoren; 18 davon wurden identifiziert: l-Hexen-3-on, 2-Acetyl-1 -pyrrolin, Dimethyltrisulfid, Methional, Phenylacetaldehyd, 2-Phenylethanol, Linalool, p-Kresol, 3,9-Epoxy-1 p-menthen, 4-Methylacetophenon, 3,9-Epoxy-1,4(8)p-menthadien (Lindenether), 1,3 -p-Menthadi-en-7-al,p-Anisaldehyd, 4-Vinylguajacol, (E)--Da-mascenon, Eugenol, Vanillin undcis-Rosenoxid. Lindenether undcis-Rosenoxid, die auch in einem Extrakt von Lindenblüten (Tilla cordata) vorkamen, fehlten in Honigen anderer botanischer Herkunft. Diese beiden Aromastoffe und das geruchlosetrans-Limonen-1,2-diol werden als Indikatoren für Linden honig vorgeschlagen. Die Geruchsschwellen (in Luft) der 18 Aromastoffe wurden bestimmt.

     

Comparing coverage quality for femtocell and macrocell broadband data services

This article presents the results of a series of field tests to characterize femtocell coverage quality in typical residential houses with respect to high-speed data services. The study proves femtocell users can expect to observe an improvement of more than five times in average airlink data speeds relative to the existing macrocell network. The article presents the methodology used in the tests, and offers summary results for both 1xEV-DO and HSDPA technologies. The results presented here show that the case for using femtocells for broadband data services is even stronger than for voice-based services.     

Quantitation of potent odorants of virgin olive oil by stable-isotope dilution assays

The potent odorants of four olive oil samples differing in flavor were quantitated, and their odor activity values (OAVs) were calculated by dividing the concentrations of the odorants in the oil samples by the flavor threshold values in the oil. The odorants with higher OAVs were contrasted with the different notes of the flavor profiles of the olive oils. It was concluded that the following compounds contributed mainly to the flavor notes given in parentheses: (Z)-3-hexenal (green), ethyl 2-methylbutyrate, ethyl isobutyrate, ethyl cyclohexanoate (fruity), (Z)-2-nonenal (fatty) and 4-methoxy-2-methyl-2-butanethiol (black-currant-like). The results showed that the calculation of OAVs is an approach to objectify the flavor differences of olive oil samples. Presented at the 83rd Annual Meeting of the American Oil Chemists’ Society, Toronto, Canada, May 10–14, 1992.     

Enzymatic oxydation of linoleic acid: formation of bittertasting fatty acids.

Linoleic acid was oxidized with a protein fraction from soya beans (25 degrees C; 2h), in which lipoxygenase and peroxydase activities occurred. The fatty acids formed were isolated and, after emulsification with a sugar ester, were evaluated for bitter taste. The main components of the bitter-tasting fractions was a mixture of 9.12.13-trihydroxyoctadec-10- and 9.10.13-trihydroxyoctadec-11-enoic acids. The taste threshold lies in the range 0.6-0.9 mumol/ml. Two further trihydroxy-acids and two oxodihydroxy-acids were also identified in the bitter-tasting fraction.     

Analysis of fat deterioration-comparison of some photometric tests

Eight photometric methods (e.g., measurement of the diene absorption, ferrous isothiocyanate test, thiobarbituric acid value test, anisidine value, Kries test) for analysis of the oxidative deterioration of fats were compared with respect to sensitivity against autoxidized methyl linoleate and methyl linolenate. The ferrous isothiocyanate test was found to be the most sensitive method followed by the measurement of diene absorption. For assessment of the specificity, highly autoxidized methyl linoleate was separated by column chromatography into the following classes of compounds: volatile carbonyl compounds, monohydroperoxides, and polar peroxides-1 and-2. The influence of each class of compounds on the results of the eight tests was determined.