Phytinsaure in Weizenkleien und Weizenkeimen. M?glichkeiten zur Entfernung der Phytinsaure

Zusammenfassung Kommerzielle Weizenkleien des Handels (9 Muster) enthielten zwischen 32 and 46 mg/g TS Phytinsäure, das entspricht einer 3- bis 5 fachen Anreicherung gegenüber Ganzkornweizen, bei Ballaststoffgehalten von 32 bis 47% FS. Weizenkeime des Handels (4 Muster) besaßen 15 bis 18 mg/g TS Phytinsäure bei Ballaststoffgehalten von 9–10% FS. Der Phytinsäuregehalt ließ sich auf unter 1% des Ausgangswertes reduzieren, wenn Weizenkleien und -keime mit Natriumcitratpuffer pH 5,25 1/2 h bei 40 °C extrahiert und mit Wasser nachgewaschen wurden. Der dabei entstehende erhebliche Substanzverlust von 34–47% bei Weizenkleien and 60–73% bei Weizenkeimen ging mit einer Erhöhung der Ballaststoffmenge (phytatfreie Weizenkleie: 55–65% FS, phytatfreie Weizenkeime: 18–26%) einher. Mit dieser sehr einfachen, schnellen Extraktion lassen sich also Weizenkleien praktisch phytinfrei herstellen, so daß mögliche negative ernährungsphysiologische Effekte bei zusätzlicher Anreicherung von Ballaststoffen ausgeschaltet werden können.

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Phytic acid in wheat bran and germ products. How to remove phytic acid from these products

Summary Commercial wheat bran (nine samples) and germ products (four samples) purchased from local shops were analysed for phytic acid, dietary fibre and ash contents. Phytic acid in wheat brans ranged over 32 to 46 mg/g dry mass and in wheat germ products over 15 to 18 mg/g dry mass, the dietary fibre contents ranged over 32 to 47% and 9 to 10%, respectively. The phytic acid level can be reduced to less than 1 % of the original content by extraction with sodium citrate buffer pH 5.25 for 0.5 h at 40 °C, followed by washing with water. As a consequence, 34–47% and 60–73% of the soluble material was lost from bran and germ products, respectively; coincidently the dietary fibre content increased to 55–65% in wheat brans and 18 to 26% in wheat germ products. Such a simple and fast method enables wheat brans to be produced practically free of phytic acid, resulting in the removal of possible detrimental effects of reduced mineral availibility by increasing dietary fibre levels.

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Veroffentl.-Nr. 5732 der Bundesforschungsanstalt für Getreideund Kartoffelverarbeitung, Detmold     

In situ X-ray diffraction study of self-forming barriers from a Cu-Mn alloy in 100 nm Cu/low-k damascene interconnects using synchrotron radiation

An in situ study of self-forming barriers from a Cu-Mn alloy was performed to investigate the barrier growth using X-ray diffraction on damascene lines. The associated evolution in interconnect texture and Cu stress was also observed. The shift in Cu diffraction peak position was used to determine the change in Mn concentration and hence, estimate the thickness of the MnSi_xO_y barrier. The observed peak shift followed a log(t) behaviour and is described well by metal oxidation kinetics, following the field enhanced diffusion model. We used multiple anneal temperatures to study the activation of the formation process, demonstrating a faster barrier formation with higher ion excitation. A strong [1 1 1] Cu texture was shown to develop during the anneal in contrast to traditional PVD barrier systems. Finally, the stress in the 100 nm Cu lines was calculated, observing a large in-plane relaxation when using a self-forming barrier due to reduced confinement.     

A novel approach to high-level switching activity modeling withapplications to low-power DSP system synthesis

We address high-level synthesis of low-power digital signal processing (DSP) systems by using efficient switching activity models. We present a technology-independent hierarchical scheme that can be easily integrated into current communications/DSP CAD tools for comparing the relative power/performance of two competing DSP designs without specific knowledge of transistor-level details. The basic building blocks considered for such systems are a full adder, a half adder, and a one-bit delay. Estimates of the switching activity at the output of these primitives are used to model the activity in more complex building blocks of DSP systems. The presented hierarchical method is very fast and simple. The accuracy of estimates obtained using the proposed approach is shown to be within 4% of the results obtained using extensive bit-level simulations. Our approach shows that the choice of multiplier/multiplicand is important when using array multipliers in a datapath. If the input signal with smaller mean square value is chosen as the multiplicand, almost 20% savings in switching activity can be achieved. This observation is verified by an analog simulation using a 16 × 16 bit array multiplier implemented in a 0.6-μ process with 3.3 V supply voltage     

A transmitter IC for TETRA systems based on a Cartesian feedback loop linearization technique

A fully integrated linearized transmitter for the next generation TETRA systems for PMR and public safety applications in a CMOS-based SiGe technology is described. The presented single-chip transmitter employs a Cartesian feedback loop technique in order to improve the linearity of the externally connected power amplifier. The transmitter is usable in a frequency range from 300 MHz up to 800 MHz, providing a linearity improvement of more than 40 dB.     

Ochratoxin A in dried vine fruit: method development and survey

A method is described for the determination of concentrations of the mycotoxin ochratoxin A in dried vine fruits (currants, raisins and sultanas) using acidic methanolic extraction,immunoaffinity chromatography clean-up and HPLC determination. The limit of detection was estimated as 0.2mug/kg, and recoveries of 63-77% were achieved at 5mug/kg. HPLC-mass spectrometric confirmation of the identity of ochratoxin was obtained. Ochratoxin A and aflatoxins were determined in 60 samples of retail dried vine fruits purchased in the United Kingdom. Ochratoxin A was found in excess of 0.2mug/kg in 19 of 20 currant, 17 of 20 sultana and 17 of 20 raisin samples examined, an overall incidence of 88% . The maximum level found was 53.6mug/kg. No aflatoxin was found in any sample analysed, using a method with a detection limit of 0.2mug/kg for each of aflatoxin B1, B2, G1 and G2.     

Modelling and prediction of phyto- and zooplankton dynamics in Lake Kasumigaura by artificial neural networks

An artificial neural network model was developed for Lake Kasumigaura to predict timing and magnitudes for chlorophyll a, five species of blue-green algae and three zooplankton groups. The model was trained by 8 years of limnological time series and validated by two independent years. The validation showed the potential of neural networks as predictive tools for highly non-linear phenomena such as blue-green algal blooms in freshwater lakes.     

Mobility degradation effects in CMOS differential pair transconductors

The influence of the mobility reduction factor on the dominant third-harmonic distortion and effective transconductance in CMOS differential pair transconductors is examined. Analytical expressions are developed which are suitable for hand calculation and generate realistic estimates for distortion and transconductance. The results produced have been tested against SPICE simulations over a wide range of parameter values and show excellent agreement. The analysis highlights the importance of mobility degradation and reveals that the linearity of the source-coupled differential pair is actually improved as the mobility reduction factor increases. This surprising finding suggests that where 0.15, for example, acceptably low distortion levels (<60 dB for V _i =1 V _pp ) should be achievable with the basic long-tailed pair and that complex linearization schemes may be unnecessary.This work is supported by a grant of the Science and Engineering Research Council.     

Time-dependent optical spectroscopy and imaging for biomedicalapplications

The application of optical spectroscopy and imaging in living tissue is complicated by multiple scattering of light. In spectroscopy, this scattering causes uncertainty in the pathlength traveled by photons in the tissue, while images suffer reduced resolution and contrast. Picosecond light sources and fast detectors have made it possible to address these problems by direct measurement of the photon time-of-flight. Diffusion models of light propagation can be used to relate the measured distribution of photon transit times to the scattering and absorption coefficients of the tissue. The advantages of absolute absorption measurement are demonstrated for two problems: determination of hemoglobin oxygenation in tissue and in vivo measurement of the uptake of an exogenous chromosphere such as photosensitizer. Optical imaging may also be improved by the elimination of multiply scattered photons or by selective detection of photons arriving from a given region of the tissue. The potential advantages of these techniques are discussed and illustrated with experimental data     

Time delay estimation using the cross bispectrum

The cross bispectrum phase can be effectively used to estimate the time required for a nonGaussian signal to propagate between a pair of spatially separated sensors in the presence of highly correlated Gaussian noise. The authors present a consistent estimator of the phase of the cross bispectrum, derive the exact distribution of the phase of a complex Gaussian sample bispectrum, and show that in most cases the exact distribution can be approximated by a Gaussian distribution. Using this Gaussian approximation, the authors derive the variance of the time delay estimate computed from the sample cross bispectrum of a signal in additive correlated noise. These results allow the performance of time delay estimators based on the cross bispectrum phase to be quantified as a function of the sample size, the skewness of the signal, the signal-to-noise ratio (SNR), and the noise correlation     

Fibre-optic based confocal scanning microscopy with semiconductor laser excitation and detection

A compact novel form of confocal scanning microscope using a semiconductor laser is described. Confocal operation is ensured by the use of a single mode optical fibre for both launching the light into the microscope and collecting the signal from the object. The collected light is allowed to reenter the laser and the image is detected as a modulation on the signal from the laser power monitor diode.<>