Production of penitrem A by Penicillium crustosum isolated from foodstuffs

Sixty one isolates of Penicillium crustosum originating from various foodstuffs were screened for penitrem A production by thin-layer chromatography. The highest producers of penitrem A (4 isolates) were grown in various liquid media. Skimmed milk (2%)/potato extract (2%)/sucrose (2%) (SPS) medium supported the highest toxin production and P. crustosum Sp 1552 was selected as the best producer of penitrem A. Optimal conditions for the production of penitrem A were to grow the isolate Sp 1552 (stationary) in 100 ml of SPS medium (with 4% sucrose) in 500-ml flasks for 3 weeks at 25 degrees C with initial pH 5.7. The isolation and purification of penitrem A is described. Approximately 246 mg of pure penitrem A was obtained from 200 flasks each containing 100 ml of SPS medium.     

Green Emission in Ladder‐Type Quarterphenyl: Beyond the Fluorenone‐Defect

In polyfluorenes it is generally accepted that (photo)degradation leads to fluorenone type defects that accept the excitation energy and emit green‐to‐yellow light with rather low efficiency. Although initial spectroscopic studies suggest the same to hold true for ladder‐type poly(para‐phenylene)s (LPPPs), kinetic studies of the degradation process are not compatible with the established mechanism. In general, the observed green emission can be caused by the introduction of carbonyl groups; however, only if associated with an additional disruption of the backbone rigidity and hence planarity of the entire π‐system. This is clearly shown by comparison with synthesized model compounds, which are bearing the fluorenone motif yet possess very different optical properties as compared to the defects, which are actually formed. Degradation can be caused by solvent specific, yet substrate nonspecific aromatic formylation but mainly originates from reaction with in‐situ generated singlet oxygen, both in solution as well as in thin films. Time‐dependent photoluminescence measurements on thin films show that green emission is enhanced by energy transfer from intact molecules to defect centers.     

An Innovative Technique for Rapid Screening of Cigarette Filter Adsorbents

Cigarette smoke is an aerosol containing a large number of chemicals, including toxicants. In recent years, a number of cigarette filter additives have been evaluated for their toxicant filtration properties. Screening is a useful tool to accelerate the testing and development of new filter additives and filtration mechanisms. The evaluation of a filter material screening technique based on the so‐called InfraSORP technology is described. By comparing InfraSORP measurements with reference cigarette smoke experiments of potential cigarette filter materials like activated carbons and ion‐exchange resin, an excellent correlation is demonstrated. This technique allows for a rapid screening of potential filter materials prior to testing any final candidates in cigarettes.     

Basic aspects of food preservation by hurdle technology

Hurdle technology is used in industrialized as well as in developing countries for the gentle but effective preservation of foods. Previously hurdle technology, i.e., a combination of preservation methods, was used empirically without much knowledge of the governing principles. Since about 20 years the intelligent application of hurdle technology became more prevalent, because the principles of major preservative factors for foods (e.g., temperature, pH, a(w), Eh, competitive flora), and their interactions, became better known. Recently, the influence of food preservation methods on the physiology and behaviour of microorganisms in foods, i.e. their homeostasis, metabolic exhaustion, stress reactions, are taken into account, and the novel concept of multitarget food preservation emerged. In the present contribution a brief introduction is given on the potential hurdles for foods, the hurdle effect, and the hurdle technology. However, emphasis is placed on the homeostasis, metabolic exhaustion, and stress reactions of microorganisms related to hurdle technology, and the prospects of the future goal of a multitarget preservation of foods.     

Screening of Porous Materials by Thermal Response Measurements

Adsorption thermal response screening by optical adsorption calorimetry was recently demonstrated to be a versatile tool for rapid surface area and adsorption capacity testing of porous materials. Beyond the high throughput approach, further insight in possibilities and application examples for the method will be presented. Especially a rapid classification of porous materials regarding their pore properties and the possibility to evaluate adsorption kinetics by using thermal response measurements will be discussed.