PubMed Health⌕ Search

Biomedical subjects

K Figge

Publications and source records attributed to K Figge.

18 recordsLinked to original sources
PubMed1997

Biodegradation of sucrose poly fatty acid esters in soils.

Sucrose polyesters (SPEs) were applied to soil at rates equivalent to 1062 to 1293 kg per hectare and incubated over periods of 100 to 403 days at 20 +/- 2 degrees C in darkness and at a soil moisture of 40% of the maximum water holding capacity. All applied forms of SPEs were aerobically biodegraded to some degree in both American and German soil. However, the mineralization rates varied considerably and were dependent on both SPE and soil type. For example, sucrose octaoleate underwent slow and limited mineralization in the German soils Speyer and Borstel as well as in the American soil Madera, reaching only 6.9-18.4% mineralisation after over 400 days incubation. The same material in the American soils Hollande, Thermal and Uvalde as well as in the German soil Speicherkoog, reached 35-52% after the same incubation period. Of the SPEs most realistic for use in food products, the more liquid (i.e. with the least saturated fatty acids) underwent the most rapid and extensive mineralization. However, the mineralization rates for these materials were distinctly lower than the corresponding ones for sucrose octaoleate. In all cases the extent of mineralization of the SPEs in soil was significantly lower than that of a control fat (synthetic triglyceride mixture HB307), which typically underwent over 50% mineralization in 60 days.

Bacteria, Aerobic↗
PubMed1991

Transformation of 3-chlorodibenzofuran by Pseudomonas sp. HH69.

The dibenzofuran-degrading bacterial strain Pseudomonas sp. HH69 showed high oxidative activity towards 3-chlorodibenzofuran (3CDF). During the co-metabolic turnover of 3CDF large amounts of 4-chlorosalicylate and temporarily small amounts of salicylate were excreted. Simultaneously a yellow colour appeared due to the excretion of two polar products. Conversion of 3CDF by a mutant, derived from Pseudomonas sp. HH69 and defective in 2,3-dihydroxybiphenyl-1,2-dioxygenase led to the formation of equal quantities of 4'-chloro-2,2',3-trihydroxybiphenyl (4'CTHBP) and 4-chloro-2,2',3-trihydroxybiphenyl (4CTHBP). Crude extracts of the wild type transformed 4'CTHBP to 4-chlorosalicylate, whilst 4CTHBP was transformed to salicylate. Hence, we propose a non-selective initial attack on both aromatic rings of 3CDF and a degradative pathway for the resulting chlorotrihydroxybiphenyls.

Benzofurans↗
PubMed1986

Kinetic distribution model for chemicals based on results from a standard environmental system.

In order to reduce potential hazards to the environment resulting from production and use of chemicals, some governments have enacted laws and corresponding regulations. Thus, for instance, the German "law on hazardous substances," and the regulation regarding a.o. submission of test data on physiochemical properties of new substances, have been ratified by the Federal Republic of Germany legislation in 1980 and 1981, respectively. This implies that before production, marketing, and use of a new chemical, its potential hazard to human beings and the environment has to be checked. Therefore it is necessary to have available accurate information about the probable fate of this new chemical in the environment, i.e., its distribution among the different environmental compartments. To this end, the submission of basic physiochemical data of a new chemical, such as boiling point, vapor pressure, water solubility, fat solubility, and partition coefficient in the system n-octanol/water, is mandatory for its registration. These data are meant to be used by the official evaluating department as a basis for describing the distribution behavior of the substance in the environment. However, there is no generally accepted procedure yet which would allow the reliable prediction. Such a calculation procedure should comprise all factors decisive for distribution and degradation of chemicals in the environment, according to their significance. We have taken a first step in this direction by carrying out the following experiments, with the aim of developing such a distribution model as well as identifying the physicochemical properties of chemicals required for the prediction of distribution patterns. The distribution patterns of 12 selected substances, having significant differences with respect to their physiochemical properties, were determined via radiotracer technique, in a defined, standardized, terrestrial ecosystem. The results of the experiments were compared with one another as well as with values calculated by use of mathematical models from the literature. These comparisons show that there are certain correlations between the distribution patterns obtained by experiments and those calculated by the stationary distribution models. However, these also indicate that some of the experimental findings cannot be explained within the framework of stationary distribution models. Kinetic models represent a more universal approach toward predicting the distribution of chemicals in an ecological system. Various prototypes are described in the literature but we could not use them due to their mathematical shortcomings.(ABSTRACT TRUNCATED AT 400 WORDS)

Chemical Phenomena↗
PubMed1984

Transfer of additives from plastics materials into foodstuffs and into food simulants--a comparison.

The transfer of stearyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate from high- and low-density polyethylenes and polypropylene as well as that of n-butyl stearate from high-impact polystyrene into several foodstuffs and into different food simulants under normal storage conditions was determined radioanalytically. Additionally, the transfer of these additives into the food simulants under the standard conditions usually requested by the authorities was determined. From these figures 'correction factors' were calculated, relating the amounts of additives transferred from the plastics materials into the foodstuffs under normal conditions of storage to the transfer of these additives from the test specimens into food simulants (e.g. olive oil and HB 307) under the standard test condition of exposure at 40 degrees C for 10 days.

Butylated Hydroxytoluene↗
PubMed1983

Testing of chemicals by evaluation of their distribution and degradation patterns in an environmental standard system.

Due to the EC directive 79/831 of September 18, 1979, and the German law on hazardous substances, the submission of test data on physical--chemical properties of new substances is mandatory for their registration. These data are supposed to predict in which compartments (air, water, soil, vegetation) the substance will primarily accumulate if it enters the environment. To calculate the distribution of a substance in the environment compartments, different mathematical models have been developed by several working groups, but have not yet been verified in practical experiments. During a prolonged period, the distribution of substances in the environment compartments has been investigated by experiments in an environmental standard system; design and function are explained. Distribution and degradation patterns of 12 reference substances will systematically be investigated, covering a wide spectrum in regard to their physical--chemical properties. Up to now 7 substances have been investigated under standard conditions. The distribution patterns established in these experiments are presented and compared with those obtained mathematically by use of the presently discussed stationary distribution models and values for the physical--chemical properties of the tested substances. The time alterations observed in the distribution patterns are interpreted by a kinetic model which will be part of the calculation method which is presently being developed on the basis of the obtained test values. The good consistency of distribution patterns established by experiments with those established mathematically justifies the assumption that a reliable calculation method of distribution patterns can be submitted as soon as our current work will be finished.

Air Pollutants, Radioactive↗
PubMedDate not supplied

Additive migration from various plastics with different processing or properties into test fat HB 307.

The migration of the antioxidant n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate from various plastics into the test fat HB 307 was investigated. Plastics from the following classes were included: high-impact polystyrene (HIPS), polypropylene (PP), high- and low-density polyethylene (HDPE and LDPE), and were found to have distinctly different properties--in particular, different densities, melt flow indices and structural characteristics. Each plastic was processed into test specimens such as pressed and extruded sheets, injection-moulded cups, deep-drawn tubs and blown bottles. The migration out of these specimens was investigated under identical test conditions. The results confirm that the amounts of additive migrating from the different classes of plastics into test fat HB 307 in general decrease in the order LDPE greater than HDPE greater than PP greater than HIPS. Moreover, it seems to be of great importance that the respective amounts of additive migrating from the injection-moulded cups, deep-drawn tubs and blown bottles into test fat were significantly lower in all cases than those from the corresponding pressed or extruded sheets. Presumably, this effect is mainly caused by orientation of the polymer molecules in the injection-moulded, deep-drawn or blown products. It is concluded that the migration of the antioxidant decreases with increasing density of the polymer and that the melt flow index (molecular weight) has hardly any influence. Migration from HIPS into fat increases with the content of impact modifier. In the case of the polyethylenes, the influence of processing on the migration rate decreases with decreasing density of the polymer.

Antioxidants↗
PubMedDate not supplied

Interaction between plastics packaging materials and foodstuffs with different fat content and fat release properties.

The migration of an addictive (phenolic antioxidant) from different types of plastic food packaging materials (low density polyethylene [LDPE], high density polyethylene [HDPE], polypropylene [PP], acrylonitrile-butadiene-styrene [ABS] and high-impact polystyrene [SB]) into low-calorie (reduced fat) foodstuffs has been determined under normal storage conditions, and shown in most cases to be equivalent to migration into normal foodstuffs. Certain exceptions are discussed and related to the fat-release properties of the particular foodstuffs. Additive transfer into low-calorie products, as well as into emulsions of fat and water, has been compared with that into aqueous acetic acid and test fat HB 307 under normal storage conditions and after 10 days at 40 degrees C. The transfer of antioxidant from plastics was found to decrease in the order LDPE, HDPE, PP, SB and ABS. Migration was found to be higher into pure fat and margarine than into mayonnaise. When comparing absorption from different emulsions of fat and water, the ranking for plastics was the same as the above with LDPE having a greater absorption than HDPE, except that ABS and PP had absorptions of the same order whilst it was significantly higher for SB. The type of emulsion was, however, found to have a greater influence on migration of the antioxidant from the polymer than on the fat absorption from the emulsion. The results are discussed in relation to earlier work and also with respect to the classification of foodstuffs.

Absorption↗
PubMedDate not supplied

Alternative fatty food simulants for migration testing of polymeric food contact materials.

The amounts of substances migrating from plastics into foodstuffs with high fat contents are in most cases higher than in foodstuffs with water contents. This increase in migration commonly is due to the higher solubility of the migrating organic compounds in fat compared to water. The increase in migration is not necessarily due to an increase in the substance's diffusion coefficient due to interactions between the fat and the plastic as is often assumed. Ethanol is a good simulant for fatty foods because it has little interaction with many plastics, e.g. polyolefins, migrants are readily soluble in it, and because it is easy to work with analytically. The utilizable limits of ethanol and ethanol/water mixtures as food simulants are developed from the physical background of diffusion. The use of ethanol and ethanol/water mixtures is supported by published experimental migration results.

Diffusion↗