Pyrolysis

Decomposition or transformation of a compound caused by heat pyrolytic.


Chemical decomposition of matter through the action of heat.


Decomposition of a compound into smaller, more reactive structures by the action of heat alone. The fragmentation is usually followed by combination of the smaller structures to more stable compounds, provided the conditions do not allow the conversion to CO and CO2. Pyrolysis products may occur in all three of the macronutrient categories. The formation of pyrolysis products depends on the type of parent compound and the temperature. In the case of food, hazardous compounds are formed from about 300°C. Well-known types of pyrolysis products in foods include polycyclic aromatic hydrocarbons (PAHs) and heterocyclic pyrolysis products from amino acids. PAHs are likely to be formed from degradation products consisting of two- or four-carbon units, such as ethylene and butadiene radicals. The most potent carcinogenic PAH is benz[a]pyrene, which has been identified in the charred crusts of biscuits and bread, in broiled and barbecued meat, in broiled mackerel, and in industrially roasted coffees. Fat is an important precursor for the formation of PAHs (in meat and fish). Furthermore, PAHs are abundantly found in smoked food, originating from the combustion of wood and other fuels. Heterocyclic pyrolysis products from amino acids include 3-amino-l,4-dimethyl-5H-pyrido(4-13)indole (precursor—tryptophan), 3-amino-l-methyl-5H-pyrido (4,3-b)indole (precursor—tryptophan), and 2-amino-5-phenylpyridine (precursor—phenylalanine). These mutagens and several structurally related substances have been isolated from the surface of protein-containing food cooking at 250°C and higher. Other mutagens, such as 2-amino-3-methylimidazo(4,5-f)quinoline and 2-amino-3,8-dimethylimidazole(4,5-f) quinoxaline, have also been isolated from different types of protein-rich foods heated at about 200°C.


The decomposition of organic matter when there is a rise in temperature.


The breakdown of organic materials due to an increase in temperature.


 


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