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45 2006

Journal of Food and Nutrition Research
Súhrny čísla 4 / 2006

ŠIMON, P. - POLAVKA, J.
Thermooxidative degradation of dried milk studied by non-isothermal thermogravimetry
Journal of Food and Nutrition Research, 45, 2006, č. 4, s. 166-170

Peter Šimon, Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, SK-812 37 Bratislava, Slovakia. E-mail: peter.simon@stuba.sk

Súhrn: Thermooxidative degradation of three samples of powder dried milk with various fat content was studied by simultaneous DTA/thermogravimetry technique under air. The oxidation onset temperatures were determined from the thermogravimetric records by using a non-isothermal approach. Contrary to the isothermal measurements, the peak of oxidation is distinct in the nonisothermal measurements and the oxidation onset temperature can be read accurately and unambiguously. From the dependence of the onset temperature on the heating rate the kinetic parameters characterizing the length of induction period of oxidation have been obtained. The parameters appeared the same for all the dried milk samples. The lengths of induction periods decrease exponentially with temperature. A sinusoidal modulation of temperature leads to a considerable decrease of thermooxidative stability of the dried milk.

Kľúčové slová: dried milk; thermooxidative stability; induction period; thermogravimetry

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