Reaction Kinetics of the Denaturation of Whey Proteins in Milk

Authors

  • FRANK DANNENBERG,

    1. Author Kessler is at the Institute for Dairy Science & Food Process Engineering, Technical University Munich, 8050 Freising-Weihenstephan. West Germany. Author Dannenberg, formerly at the Technical University Munich, is now with NESTEC Ltd., Nestlé Research Centre, Vers-chez-les-Blanc, 1000 Lausanne, Switzerland.
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  • HEINZ-GERHARD KESSLER

    1. Author Kessler is at the Institute for Dairy Science & Food Process Engineering, Technical University Munich, 8050 Freising-Weihenstephan. West Germany. Author Dannenberg, formerly at the Technical University Munich, is now with NESTEC Ltd., Nestlé Research Centre, Vers-chez-les-Blanc, 1000 Lausanne, Switzerland.
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  • This study has been supported by the DFG (Deutsche Forschungsgemeinschaft).

ABSTRACT

The kinetics of the neat-induced irreversible denaturation of β-lacto-globulins (β-LG) A and B and of α-lactalbumin (α-LA) in milk were examined over a wide temperature/time range (70-150°C, 2-5400 sec). Denaturation of β-LG was best described with an apparent reaction order of 1.5 (α-LA; first order). The abrupt changes in the temperature dependence of the rate constants (β-LG at 90°C, α-LA at 80°C) were interpreted in terms of the different activation energies and entropies occurring in the two temperature ranges. By using the kinetic parameters for calculating lines of equal degrees of denaturation in a plot of log-time versus 1/absolute temperature it was possible to predict the effect of different heat treatments on the denaturation of individual proteins.

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