Journal of Food Technology

Year: 2012
Volume: 10
Issue: 2
Page No. 17 - 23

Thermodynamics of Heat Inactivation of Listeria monocytogenes in Soymilk of Varying Initial pH and Sugar Values

Authors : M.A. Igyor, C.C. Ariahu and C.U. Inyang

Abstract: The thermodynamics of heat destruction of Listeria monocytogenes in soymilk of varying initial pH (6.0-6.8) and sugar contents (0.5-10% w/v) were studied using kinetic parameters generated via the classical thermobacteriology assumption of a log-linear relationship between Listeria monocytogenes survivors and heating time (0.5-30 min at 50-65°C). The activation enthalpy (ΔH+), entropy (ΔS+), Energy (Ea) and frequency factor (k0) for the heat inactivation ranged, respectively, from about 275-302, 612-705 J/mol deg., 277-305 kJ/mol and 2.9x1043-2.0x1048 min-1 increasing with increases in initial sugar contents and acidity of soymilk. A kinetic compensation effect was observed for both ΔS+/ΔH+ and ln k0/Ea relationships with isokinetic temperature of 32.16x0.13°C and isokinetic destruction rate constant of 9.21x10-5 min-1 for the microbe in soymilk.

How to cite this article:

M.A. Igyor, C.C. Ariahu and C.U. Inyang, 2012. Thermodynamics of Heat Inactivation of Listeria monocytogenes in Soymilk of Varying Initial pH and Sugar Values. Journal of Food Technology, 10: 17-23.

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