RESUMO
To investigate the possible presence of protein-bound mutagens in food an analytical procedure has been devised in which the sample is enzymically hydrolysed, fractionated by HPLC and examined by a modified liquid incubation Ames assay. To validate the method MeIQx was added, as a model compound, to beefburger and a recovery of 82% obtained. The limit of detection for protein-bound mutagens was 1 microgram/kg, expressed as equivalents of MeIQx. No detectable mutagenicity was observed when the procedure was applied to samples of well cooked beefburger, irradiated chicken or mycoprotein.
Assuntos
Análise de Alimentos/métodos , Contaminação de Alimentos , Mutagênicos/isolamento & purificação , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , Enzimas , Hidrólise , Carne , Testes de Mutagenicidade , Quinoxalinas/isolamento & purificaçãoRESUMO
A method for the measurement of o-tyrosine in irradiated chicken has been developed. The procedure involves the solvent extraction and removal of free o-tyrosine, which is present in unirradiated tissue, followed by acid hydrolysis of bound o-tyrosine in the proteinaceous residue and measurement of the cleaved residues by HPLC with fluorescence detection. Bound o-tyrosine was not detected above 0.01 mg/kg in unirradiated tissue but was observed, in increasing amounts of up to 5.18 mg/kg, when the tissue was irradiated at doses of between 2.5 and 20 kGy. The precision of the analysis was assessed by duplicate determinations, the agreement between duplicates and their respective means averaged 1.7% as defined by the term [(a-b)/(a+b)] x 100% where a and b are the repeat determination values.
