Toxicological potential of 2-alkylcyclobutanones--specific radiolytic products in irradiated fat-containing food--in bacteria and human cell lines.

Food irradiation has been considered as a safe processing technology to improve food safety and preservation, eliminating efficiently bacterial pathogens, parasites and insects. This study aims to characterize the toxicological potential of 2-alkylcyclobutanones (2-ACBs), radiolytic derivatives of triglycerides, formed uniquely upon irradiation of fat-containing food. In irradiated food they are generated proportionally to fat content and absorbed radiation dose.

Determination of 2-alkylcyclobutanones with electronic impact and chemical ionization gas chromatography/mass spectrometry (GC/MS) in irradiated foods.

The use of a column containing 60 g of silica gel for cleanup and the use of isobutane as a reactant reagent for chemical ionization-mass spectrometric analysis of the saturated and monounsaturated alkyl side-chain 2-alkylcyclobutanones (2-ACBs; specifically induced by irradiation from fat in foods until the proof of contrary) has improved both the sensibility and the selectivity of the method when applied for the detection of irradiated foods. The quality of the chromatograms obtained was improved, allowing the detection of food samples (avocados) irradiated at low doses (0.1 kGy) or irradiated ingredients included in low proportions (less than 5%, wt/wt) in nonirradiated culinary foods.

Use of the DNA Comet Assay to detect beef meat treated by ionizing radiation.

The DNA Comet Assay has been described as a rapid and inexpensive screening test to identify radiation treatment of food. In this work, this method was applied to detect the treatment of beef meat pieces either by gamma rays or electron beam. The dose levels were 2.

Determination of monounsaturated alkyl side chain 2-alkylcyclobutanones in irradiated foods.

The 2-alkylcyclobutanones (2-ACBs) are formed from triglycerides by irradiation treatment and may be used as markers for this type of food processing. This paper describes a detection method for the analysis of monounsaturated alkyl side chain 2-ACBs, which is formed upon irradiation from monounsaturated fatty acids which frequently are the most abundant fatty acids in foods. The estimated radioproduction yields of the cis-2-(dodec-5'-enyl)-cyclobutanones (cis-2-dDeCB) and the cis-2-(tetradec-5'-enyl)-cyclobutanones (cis-2-tDeCB) were 1.

Food-borne radiolytic compounds (2-alkylcyclobutanones)may promote experimental colon carcinogenesis.

Food irradiation is acknowledged as a safe process to improve food quality by reducing microbial contamination. Information on the toxicological potential of 2-alkylcyclobutanones (2-ACBs), radiolytic derivatives of triglycerides found exclusively in irradiated food, is scarce. Wistar rats received daily a solution of highly pure 2-tetradecylcyclobutanone (2-tDCB) or 2-(tetradec-5-enyl)-cyclobutanone (2-tDeCB) at a concentration of 0.

Detection of 2-alkylcyclobutanones, markers for irradiated foods, in adipose tissues of animals fed with these substances.

Laboratory rats received a freshly prepared drinking fluid containing 0.005% 2-tetradecyl- or 2-tetradecenyl-cyclobutanones daily for 4 months. These two compounds were recovered in the adipose tissues of the animals that consumed them.

Moderate intervention with carotenoid-rich vegetable products reduces lipid peroxidation in men.

Because of their antioxidant properties, carotenoids may have beneficial effects in preventing cancer and cardiovascular disease. However, in humans consuming carotenoid-rich vegetables, data concerning the antioxidant effects of carotenoids are rather scarce. A human intervention trial was conducted, therefore, to determine whether a moderately increased consumption of carotenoid-rich vegetables would influence the antioxidant status in 23 healthy men.

The DNA 'comet assay' as a rapid screening technique to control irradiated food.

The exposure of food to ionizing radiation is being progressively used in many countries to inactivate food pathogens, to eradicate pests, and to extend shelf-life, thereby contributing to a safer and more plentiful food supply. To ensure free consumer choice, irradiated food will be labelled as such, and to enforce labelling, analytical methods to detect the irradiation treatment in the food product itself are desirable. In particular, there is a need for simple and rapid screening methods for the control of irradiated food.

[International cooperation on the detection of irradiated food].

A survey over recent international developments to detect the irradiation treatment of foods is given, in particular the programmes of "ADMIT" (FAO/IAEA) and of BCR (European Community). The need to detect radiation treatment by analysing the food itself is desirable to check compliance with existing regulations, such as the enforcement of labelling and control of prohibition, to enhance consumer confidence in the correct application of radiation processing, and to protect consumers' freedom of choice between irradiated or unirradiated food products. Some larger collaborative studies on an international scale have already taken place, e.

Vitamin E deficiency in rabbits receiving a high PUFA diet with and without a non-absorbable antioxidant. II. Incorporation of 14C-labelled glycine and L-leucine into liver and plasma proteins.

As determined by in vivo studies using [1-14C] L-leucine and [1-14C] glycine, vitamin E deficiency in young rabbits caused a higher turnover rate of liver proteins and of plasma albumin and globulin fractions. This effect was most clearly and consistently observed in animals fed a diet containing 10 mg of the non-absorbable polymeric antioxidant Anoxomer per g of fat in the diet.

Structural investigation of radiation-induced aggregates of ribonuclease.

Following irradiation of bovine pancreatic ribonuclease in aqueous solution with 60Co gamma-rays protein aggregates are formed. The nature of the bonds linking these radiation-induced aggregates together has been investigated by chromatographic and electrophoretic methods. Thin-layer gel filtration and polyacrylamide gel electrophoresis, both in the presence of sodium dodecyl sulphate, demonstrated the existence of covalent crosslinks between the aggregates.

[Radiation-induced aggregation of proteins: binding of amino acids to myoglobin (author's transl)].

When myoglobin is irradiated in the presence of amino acids, the most radiation-reactive species, like the aromatic and sulfur-containing amino acids, will bind preferentially to the protein. The radiation-induced binding is strongly dependent on the concentration of protein and amino acid. Subsequent to irradiation of myoglobin in the presence of radioactively labelled tryptophan followed by tryptic hydrolysis, only a single radioactive spot was detected on the fingerprint.

Structural damage of gamma-irradiated ribonuclease revealed by thin-layer isoelectric focusing.

Ribonuclease, irradiated with 60Co gamma-rays in dilute aqueous solution or in the dry state, has been investigated with respect to its charge and size properties. Thin-layer isoelectric focusing revealed extensive change in irradiated RNase; new enzymatically-active components, mainly with isoelectric points lower than in unirradiated RNase were observed. Thin-layer gel chromatography indicated the formation of aggregates which are partially active enzymatically.

Fractionation of horseradish peroxidase by preparative isoelectric focusing, gel chromatography and ion-exchange chromatography.

Horseradish peroxidase has been fractionated by preparative isoelectric focusing in a density gradient and in a layer of granulated gel using pH-3-10 and narrow-pH-range carrier ampholytes at different total enzyme loads. The resolution of peroxidase isoenzymes in preparative-layer isoelectric focusing was comparable to that obtained by analytical thin-layer isoelectric focusing. Isoelectrically homogeneous isoenzymes could be isolated with good recovery in a single fractionation step.