Degradation and conversion of thiamin and thiamin phosphate esters in fresh stored pork and in raw sausages.

Pork samples were extracted with trichloroacetic acid (4%) and analyzed for thiamin (T) and thiamin phosphate esters with high performance liquid chromatography (HPLC). The following concentrations (on protein basis) were found in samples analyzed 0.5h after slaughter: non-phosphorylated T, 1.0nmol/g; thiamin monophosphate (TP), 1.3nmol/g; thiamin diphosphate (TP(2)), 9.1nmol/g; and thiamin triphosphate (TP(3)), 65.7nmol/g. A fifth substance was also detected, which has not yet been identified in pork and may be related to thiamin tetraphosphate (TP(4)) or adenosine thiamin triphosphate (ATP(3)); when calculated as thiamin tetraphosphate the content (on protein basis) of the fifth substance was 15.0nmol/g. After 216h storage, the contents (on protein basis) of T and TP had changed as follows: 46.3nmol/g T; 3.2nmol/g TP, 5.0nmol/g TP(2), and 12.5nmol/g TP(3), The fifth substance completely degraded within 6h. These changes are probably due to the instability of highly phosphorylated thiamin phosphate esters, which undergo dephosphorylation during storage. In addition, there was a decrease in total thiamin concentrations (on protein basis) during the first 24h of storage from 92.1nmol/g to 24.0nmol/g, followed by an increase to 67.0nmol/g over a 216h storage period. One possible explanation for the decrease observed during the first 24h might be that thiamin is converted into a reversible, binding form that cannot be extracted by trichloroacetic acid.

Thiamin phosphates in egg yolk granules and plasma of regular and embryonated eggs of hens and in five- and seven-day-old embryos.

The thiamin (TH), thiamin monophosphate (TMP), thiamin diphosphate (TDP), and thiamin triphosphate (TTP) content was analyzed in yolk plasma and yolk granules of unincubated and incubated chicken eggs and in 5- and 7-day-old chick embryos. Analytes were extracted from samples weighing approximately 1 g, with trichloroacetic acid (0.4 g/L), isolated with solid-phase extraction, and determined with HPLC. Before solid-phase extraction with a C-18 cartridge and a strong anion exchange cartridge, analytes were converted to thiochromes with cyanogen bromide. For HPLC, a C-8 pre-column and a C-8 column connected to a NH(2) column were used with a fluorescence detector. No thiamin phosphates were found in egg yolk plasma or granules in native and embryonated eggs. The TH content in DM was 3,400 +/- 700 ng/g for yolk plasma, 1,500 +/- 140 ng/g for yolk granules of unincubated eggs, and 4,400 +/- 1,100 ng/g for yolk plasma and 2,100 +/- 450 ng/g for yolk granules of 5-d embryonated eggs. In chick embryos, TH as well as thiamin phosphates were found. The mean content in 5-d-old embryos was 1,200 +/- 400 ng of TH and 8,000 +/- 1,000 ng of TDP/g of DM. In 7-d-old embryos, the content of TH was 900 +/- 200 ng, TMP was 400 +/- 200 ng, and TDP was 5,500 +/- 1,300 ng/g of DM. Thiamin triphosphate was not detected, and the minimum detectable limit for T was 0.3 ng/mL, for TMP 0.5 ng/mL, and for TDP 0.9 ng/mL, respectively. Recovery was 71% for TMP and 64% TDP in plasma and 58% TMP and 47% TDP in granules. It was demonstrated that only TH is present in egg yolk fractions in native and embryonated eggs of hens and that thiamin phosphates can be found in 5- and 7-d-old embryos, which indicates that they are synthesized by the chick embryo. According to its assumed unique role in highly specialized tissues, TTP was not found in early embryos.

Exploring the relationship between protein secondary structures, temperature-dependent viscosities, and technological treatments in egg yolk and LDL by FTIR and rheology.

Egg yolk and its main component, low-density lipoproteins (LDL), were consecutively pasteurised, optimally freeze-dried, and dispersed in various NaCl solutions (0-10%). Heat-induced changes in the protein secondary structures which accompanied viscosity-increasing aggregation processes were monitored using Fourier transform infrared spectroscopy (FTIR) to determine the intensities of intermolecular ß-sheets (1622 cm(-1)) and results were compared with the temperature-dependent viscosities. Considerable changes in secondary structures observed after reconstitution of freeze-dried LDL had no detectable effect on the characteristic heat-induced viscosity curves but suggest that LDL plays a particular role in the unwanted gel formation of egg yolk after conventional freezing. For all egg yolk samples and all NaCl-containing LDL samples, the sigmoidal changes in the absorbance units vs. temperature curves corresponded with the first increase in heat-induced viscosity. Both analytical methods showed that the presence of ionic strength caused a shift in curve progressions towards higher temperatures, indicating increased thermal stability.

Determination of RS,E/Z-tocotrienols by HPLC.

Synthetic alpha-tocotrienol was separated into four geometrical E/Z side chain isomers by preparative HPLC (permethylated beta-cyclodextrin phase). The isolated isomers were resolved in ethylene glycol dimethyl ether, converted into the corresponding methyl ether using dimethyl sulfate, and the tocotrienol methyl ethers were extracted with n-hexane. A subsequent HPLC separation on a chiral phase (adsorbent cellulose derivated with 3,5-dimethyl phenyl carbamate) discriminates between the enantiomers of each E/Z side chain isomer, achieving the complete resolution of the eight occurring synthetic RS,E/Z-alpha-tocotrienols. The method can be shortened by omitting the preparative separation of the E/Z tocotrienol isomers prior to the chromatography on the chiral dimethyl phenyl carbamate phase. The simplified method achieved the following separation: RS,E/Z-alpha-tocotrienol separated into five peaks, RS,E/Z-beta-tocotrienol into eight, RS,E/Z-gamma-tocotrienol into six and RS,E/Z-delta-tocotrienol into eight peaks. The naturally occurring R,E-E-tocotrienol isomer could be identified within the synthetic RS,E/Z-isomers by co-chromatography with tocotrienol methyl ethers derived from natural sources, respectively.

Congener-specific analysis of toxaphene in eggs of seabirds from Germany by HRGC-NCI-MS using a carborane-siloxane copolymer phase (HT-8).

A method for the congener-specific analysis of toxaphene in eggs of seabirds from a monitoring program from the northern part of Germany was carried out. The method was optimized in most steps of the procedure: injection temperature, HRGC with an HT-8 column, ion source temperature and the MS detection mode NCI/SIM measuring the isotope clusters of [M] , [M-Cl]-, [M-HCl]- and [M-2Cl]-. The suitability of 1,4-exo, 7,8,9,10,10-heptachloro-5-methoxytricyclo [5,2,1,0(2,6)]dec-3,8-diene as internal standard was demonstrated. 14 toxaphenes with Parlar numbers and more than 60 unknown toxaphenes could be identified. Spatial and temporal trends of toxaphene contamination are presented by using the Parlar 22 components standard for quantification.

Effect of dietary supplementation with rosemary extract and alpha-tocopheryl acetate on lipid oxidation in eggs enriched with omega3-fatty acids.

The antioxidant effect of dietary supplementation with 500 or 1,000 mg/kg of a commercial rosemary extract vs. 200 mg/kg of alpha-tocopheryl acetate (alpha-TA) on the lipid oxidative stability of omega3-fatty acid (FA)-enriched eggs was compared. Lipid oxidation was measured in fresh eggs by the lipid hydroperoxide level and malonaldehyde content. Stability to iron-induced lipid oxidation was also measured. Results showed the clear antioxidant effect of dietary alpha-TA supplementation on omega3-FA enriched eggs. In contrast, dietary supplementation with rosemary extract showed no effect on any of the lipid oxidation parameters evaluated.

Antioxidative constituents of Rosmarinus officinalis and Salvia officinalis. I. Determination of phenolic diterpenes with antioxidative activity amongst tocochromanols using HPLC.

The strong antioxidative activity of Rosmarinus officinalis and Salvia officinalis is caused by phenolic diterpenes. Extracts of these herbs are used as additives to stabilize fat and fat-containing foodstuffs against oxidation. To determine the concentration of individual phenolic diterpenes in pure extracts and fats an HPLC method with electrochemical detection has been developed.

Antioxidative constituents of Rosmarinus officinalis and Salvia officinalis. II. Isolation of carnosic acid and formation of other phenolic diterpenes.

The phenolic diterpene carnosic acid appears to be the main substance for general oxidation leading to artifacts with gamma- or delta-lactone structure in extracts of Rosmarinus officinalis and Salvia officinalis. Until now it was only possible to prepare carnosic acid by hydrogenolysis of carnosol. A semipreparative HPLC method has been developed isolating carnosic acid among other phenolic diterpenes. The separated substances were identified by 13C-nuclear magnetic resonance (NMR), 1H-NMR, mass and IR spectroscopy. Conversion of carnosic acid and carnosol to other phenolic diterpenes was investigated by HPLC.

HPLC separation of flavonols, flavones and oxidized flavonols with UV-, DAD-, electrochemical and ESI-ion trap MS detection.

The cation-induced or electrochemical oxidation of flavonols has been reported to yield 2-(hydroxybenzoyl)-2-hydroxy-3(2H)-benzofuranone. Two new gradient reversed phase HPLC methods are presented which allow the determination of those oxidized flavonols simultaneously with flavonols and flavones. UV and electrochemical detection are used because of their high sensitivity. Qualitative detection together with quantification of all compounds is achieved with photodiode-array detection. An electrospray ionization ion trap mass spectrometric method is presented for unique identification of the benzofuranones after HPLC separation.

Antioxidative constituents of Rosmarinus officinalis and Salvia officinalis. III. Stability of phenolic diterpenes of rosemary extracts under thermal stress as required for technological processes.

The concentration of phenolic diterpenes in commercially available extracts of Rosmarinus officinalis (rosemary) determined by HPLC with electrochemical detection ranged from 2.8 to 22.5%. Antioxidant activity of extracts under simultaneous storage and thermal stress depended directly on the concentration of phenolic diterpenes. Differences in rates of degradation of individual phenolic diterpenes at different temperatures were obtained.

[Chronic thallium intoxication in five German pointers of one litter]. / Chronische Thalliumvergiftung bei fünf Deutsch Drahthaar Vorstehhunden aus einem Wurf.

The difficulty of diagnosis and therapy of chronic thallium intoxication is described in five German Pointers with the same skin disease. The detection of thallium in cases of skin lesions like the cutaneous erythema with oedema and crusts or in chronic cases with multifocal alopecia is difficult. The first diagnostic information was gathered in this case from the high thallium level in the urine. The thallium concentration in the hair is subject to great variations, even in physiologic conditions. The trichogramme showed in this case pathognomonic changes like adhesion of the hair follicles. Differential diagnosis for this symmetric alopezia without pruritus are hormonal disturbances or, in puppies, the generalized form of demodicosis. The five affected dogs were treated with Fe III-Hexacyanoferrat. The clinical appearance of the skin improved slowly during a period of 1-2 months.