| Popis: |
The biogenic amines are low-weight organic bases that exhibit variable biological activity. Approximately 30 vasoactive and psycoactive amines have been found in foodstuffs. Histamine, tyramine, phenylethylamine, tryptamine, cadaverine, putrescine, spermine, and spermidine are examples of biogenic amines detectable in meat and its derivatives. These amines occur naturally in animals, plants, and microorganisms owing to their natural metabolic processes, and are usually formed by decarboxylation of amino acids.Histamine, 5-imidazol-ethylamine (MW 111), is produced by oxidative decarboxylation of histidine, and decarboxylase-positive microorganisms are able to produce it as a byproduct of their action on host tissues. This process, associated with enterobacteria such as Escherichia, Salmonella, Clostridium, and Bacillus, can be fast if the meat storage conditions are inadequate.Additionally, because of its nonvolatile behavior, histamine may bestow toxicity on the product even before it is considered decayed or organoleptically unacceptable. Secondary amines such as piperidine and pyrrolidine can be produced in the catabolism of histamine, and they, in turn, are precursors of nitrosamines, substances with known carcinogenic activity. Some cases of histamine toxicity have been reported. |
