The aim of this study was to establish the conditions for malonic dialdehyde liberation from smoked fish and curing smoke condensates, as well as to determine its content in smoked fish.

The specific absoprtion peaks of coloured solutions of malonic dialdehyde, from curing smoke condensates, with 2-thiobarbituric acid were determined. The conditions for malonic dialdehyde liberation were established, i.e. time and degree of alkaline hydrolysis of condensate, degree of distillation of acidified condensate solution, the conditions of coloured solution development, determination of extinction and method of calculation of malonic dialdehyde content in smoked fish, in individual layers of smoked mackerel fillets. The mechanism of formation of polycyclic aromatic hydrocarbone and hydrogen peroxide or hydroxyl free radicals, formed during pyrolysis of organic compounds in the presence of liberated malonic dialdehyde, was proposed.