Evaluation of white rot decay in phenol-formaldehyde resin treated European beech (Fagus sylvatica L.) LVL by drilling resistance measurements

Improving the properties of laminated veneer lumber (LVL) through wood modification expands its usage as building material, especially for outdoor applications. The outdoor performance of LVL products needs to be tested against different biotic agents, and methods are needed for testing and evaluating their effect on the structural integrity of LVL. In this study, drilling resistance (DR) measurements were used to quantify the effect of fungal decay in phenol-formaldehyde (PF) resin treated European beech (Fagus sylvatica L.) LVL caused by white rot fungi. Material specific peculiarities and their effect on the evaluation method were studied such as the effect of drill bit blunting, moisture content (MC), drilling direction and PF resin content on the DR of PF-modified LVL. The drilling direction in relation to veneer and glue layers had a significant effect on DR and feeding resistance (FR). The PF resin treatment increased the DR. Feeding resistance was found more sensitive to the blunting of the drill bit than DR. The effect of MC on DR and FR was found to be insignificant. The effect of PF resin content on the prediction of mass loss (ML) by DR became prominent only for ML by white rot decay below 10 %. Correlations between DR, ML due to fungal decay and weight percent gain were established and described with a two-factor regression model. The drill bit feed rate of 0.5 m min^?1 and the rotational frequency of 3500 min^?1 as well as the transversal drilling in relation to the veneer (glue) layers were recommended for the assessment of beech LVL treated with PF resin. The DR measurements showed high potential as a fast standard evaluation method for decay and strength loss of LVL products.

     

Wood surface discolouration due to simulated indoor sunlight exposure

Wood surface colour is a very important quality criterion in the utilisation of wood, especially in indoor applications. In this study, an attempt was made to analyse wood surface discolouration due to artificial indoor light irradiation of the most frequently traded wood species in Europe altogether. Sixteen wood species, twelve hardwood and four softwood species, were exposed for 120 hours to a xenon-arc lamp equipped with a 3 mm window glass filter, in order to simulate natural sunlight behind a window glass. Eleven wood species were chosen and further exposed to irradiation for up to 600 hours. Colour measurements were performed by means of a colorimeter device on exposed and non-exposed areas of the samples. Using the CIE-L*a*b* colour measuring system, wood surface discolouration was measured and calculated according to ?L*, ?a*, ?b* and ?E* values. An idea of the different behaviour of these species and how they relate to each other could be given.     

The effects of various processing conditions on a protein isolate from Lupinus angustifolius

Lupin protein is a promising ingredient in functional foods because of its purported hypocholesterolaemic and hypotensive activities. In this study a lupin protein isolate from Lupinus angustifolius was thermally and mechanically treated and the effects on its protein profile were determined. As a preliminary step, the main protein components of L. angustifolius were identified, using the canonical proteomic approach, including 2D-separation and mass spectrometry and, whenever necessary, also “de novo peptide sequencing”. Most of the main spots were assigned to the major lupin storage proteins: α-conglutin, β-conglutin, γ-conglutin, and δ-conglutin. The protein degradation induced by the different treatments was studied via differential scanning calorimetry (DSC), 2D-electrophoresis, and mass spectrometry, in order to get the fingerprint of the intact peptides after processing. The results indicate that, even after harsh industrial processing, α-, β- and δ-conglutin are still able to release stable peptides, although they are completely or partially degraded, as shown by the 2D protein profiles and the DSC graphs.     

Etablierung eines Frühwarnsystems zur Erkennung lebensmittelbedingter Risiken in Bayern – risikoorientierte Lebensmittelüberwachung weiter gefasst

Recent and past food scandals highlight the urgent need for food safety authorities to anticipate future risks in order to enable improved and proactive response mechanisms. With this goal in mind, the Bavarian Health and Food Safety Authority (LGL) has established an early warning system aimed at early identification of potential health risks and fraudulent practices in the food sector. The early warning approach allows intervention at different stages of risk development. On the one hand, the scanning of a broad area of the food production chain (horizon scanning) may enable prospective risk identification. To this end, relevant factors of influence (drivers) need to be identified, observed and analyzed. On the other hand, the retrospective analysis of case studies may unravel novel cause-effect associations that could be transferred to other products and production technologies, possibly leading to the identification of new drivers (root cause analysis). Additionally, various datasets emanating from food safety authorities, for example data from the European Rapid Alert System for Food and Feed (RASFF) and from Bavarian-wide laboratory analyses and food business inspections, will be closely observed and analyzed. The multidisciplinary character of the LGL has proven to be essential for the realization of the early warning approach, the analysis of inflowing data and implementation of consequences such as food business inspections and sampling for analysis. This article details the objectives and methodical approaches of the project. The acquisition of systematically compiled information as well as its analysis and assessment are comprehensively described. The early warning system presented here has already contributed significantly to the risk-oriented food inspection practiced to date, by integrating novel risk-relevant aspects.     

Verfahren zur Bestimmung verschiedener Mykotoxine in Lebensmitteln

Zusammenfassung Es wird ein einfaches Analysenverfahren für die Bestimmung von Aflatoxin B₁, B₂, G₁, G₂, M₁ und M₁, Sterigmatocystin, Penicillinsäure und Patulin in verschiedenen Lebensmitteln beschrieben.Die Mykotoxine lassen sich mit Essigsäureethylester extrahieren. Die Extrakte werden säulenchromatographisch an Mini-Kieselgel-Fertigsäulen vorgereinigt. Die Gehalte der einzelnen Mykotoxine werden nach der dünnschichtchromatographischen Auftrennung fluoro-densitometrisch ermittelt. Eine beträchtliche Erhöhung der Fluorescenzintensitäten kann durch Besprühen der Platten mit Paraffin nach dem Entwickeln erreicht werden. Die Nachweisgrenzen der fluorescierenden Mykotoxine und der fluorescierenden Derivate von Penicillinsäure und Sterigmatocystin können dadurch auf 1/10 bzw. 1/100 herabgesetzt werden.Patulin wird am empfindlichsten durch Messung der Fluorescenzlöschung bestimmt.

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A screening method for the determination of various mycotoxins in food

Summary A simple analytical method for multiple mycotoxins was developed for detecting aflatoxin B₁ B₂, G₁, G₂, M₁, and M₂, sterigmatocystin, penicillin acid, ochratoxin A and patulin. These mycotoxins were extracted with ethyl acetate. The extract was cleaned up by chromatography on silica mini-column. Each fraction was separated by thin-layer chromatography. The final evaluation of the TLC-plates was carried out by fluorodensitometry.A considerable increase in fluorescence intensity was achieved by spraying the plates with paraffin after development. The detection limits of fluorescent mycotoxins and the fluorescent derivates of penicillic acid and sterigmatocystin were lowered to 1:10 up to 1:100.Spots of patulin were measured by fluorescence quenching.

     

Antarctic springtime depletion of atmospheric mercury

Unlike other heavy metals that are inherently associated with atmospheric aerosols, mercury in ambient air exists predominantly in the gaseous elemental form. Because of its prolonged atmospheric residence time, elemental mercury vapor is distributed on a global scale. Recently, Canadian researchers have discovered that total gaseous mercury levels in the lower tropospheric boundary layer in the Canadian Arctic are often significantly depleted during the months after polar sunrise. A possible explanation may involve oxidation of elemental mercury, followed by adsorption and deposition of the oxidized form, leading to an increased input of atmospheric mercury into the Arctic ecosystem. Here we present the first continuous high-time-resolution measurements of total gaseous mercury in the Antarctic covering a 12-month period between January 2000 and January 2001 at the German Antarctic research station Neumayer (70 degrees 39' S, 8 degrees 15' W). We report that mercury depletion events also occur in the Antarctic after polar sunrise and compare our measurements with a data setfrom Alert, Nunavut, Canada. We also present indications that BrO radicals and ozone play a key role in the boundary-layer chemistry during springtime mercury depletion events in the Antarctic troposphere.